#visual-fx | Unreal Source | Page 19

south gyro Jul 19, 2018, 7:48 PM

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k enabled.

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and I've added it.

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Cool I didn't know this even existed lmao

obtuse seal Jul 19, 2018, 7:49 PM

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ok so you can set that up to line up your sprite particles in a grid

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from there you need to do some math with exec index to get the desired subimage index

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e.g. you know how many sprites wide and how many sprites tall your grid will be, uh gimme a sec

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I can just copy this from laying out a render target

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actually nevermind that, subimageindex uses a table

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@south gyro What range of subimageindices do you need?

south gyro Jul 19, 2018, 7:54 PM

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Hmm in accordance to what in particular? Right now I use from 0 to 35

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based of a 6 by 6 UV that I've set.

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or am I going about this in a wrong way?

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This is completely unknown territory for me haha

obtuse seal Jul 19, 2018, 7:55 PM

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Seems fine to me

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@south gyro To assign the desired subimageindex you can just assign the particles execution index

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awkward bit is that there's not a module or dynamic input to get execution index for a float yet so you have to write your own

south gyro Jul 19, 2018, 8:01 PM

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Oh hmm lol

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Gotcha

obtuse seal Jul 19, 2018, 8:03 PM

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Uh, I haven't made a new DynamicInput myself so I just did it in a module

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https://gyazo.com/20189eea0243291b06753b459cb87376

Gyazo

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Just something simple like that

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And the stack will look something like this https://gyazo.com/5633c59c761ba7f0a83827bb2285e377

Gyazo

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May or may not have to do some additional math to get the desired subimageindex if it doesn't happen to line up with the grid layout

south gyro Jul 19, 2018, 8:11 PM

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Gotcha let me try it out. How did you attach that module you made ? or is it global?

obtuse seal Jul 19, 2018, 8:12 PM

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When you make a new module you can just toss it into any emitter

south gyro Jul 19, 2018, 8:16 PM

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Gotcha was able to at least get it to compile correctly. I'll try and mess with the executionindex stuff.

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to see if I can get the math right.

obtuse seal Jul 19, 2018, 8:17 PM

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Essentially once you have the desired subimage for each particle then you just add a Add Velocity From Point or generally Add Velocity module in the Particle Spawn stack to provide the explosion force

south gyro Jul 19, 2018, 8:18 PM

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Perfect, thank you for your help 😃

indigo jolt Jul 19, 2018, 8:58 PM

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there's vfx that spawn when destruction triggers

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THEN there's destruction when the broken CHUNK dies

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step 1 - main mesh breaks into chunks (first vfx plays)

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step 2 - chunks fall to ground and disappear (2nd vfx plays)

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i'm not sure which slot is which, but both slots have a purpose

indigo jolt Jul 19, 2018, 9:33 PM

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might require more setup - maybe in bp, dunno

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i know it's something i've seen done that way

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on projects i've been on

hushed dawn Jul 20, 2018, 3:45 AM

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anyone know if you can spawn another particle on particle death?

celest birch Jul 20, 2018, 9:07 AM

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ive put together this dissolve/construction material for our purposes and it would be a shame not to share so if anyone needs the code ill copy paste it into a txt file
https://media.giphy.com/media/24dd5Gwk7c2DSBmyc3/giphy.gif

Giphy

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@celest birch Oh wow, kickass fx. I wouldnt mind taking a look at it! 😃

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📎 construction_dissolve.txt

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tell me if youre missing any inputs

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also material is blend masked

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No inputs missing, jsut textures 😃 for the Emiisve scan lines.

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any noise will do

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That is one hell of a node setup.

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It really takes alot of nodes to get something awesome deosnt it?

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ye and "only" 50 instructions

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yes it does

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Very clean setup too.

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Good structure.

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was only a pain to make a gradient line

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oh man that is so cool

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So cool man ty for sharing!! Going to use it as a refrence to study. Ty!

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np

hasty plank Jul 20, 2018, 12:10 PM

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anyone know why my particle effect disappears when i launch the game? https://gyazo.com/e9daa846f773b280699b282e7f527475

Gyazo

▶ Play video

obtuse seal Jul 20, 2018, 3:06 PM

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I espy a commit referencing Fur simulation in the Niagara Content Examples 👀

short sorrel Jul 20, 2018, 5:56 PM

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All, I'm just trying to build a snow footprint (normals only), however I'm not succeeding, since you can see the whole square around the footstep AND depth is practically non-existent:
https://gyazo.com/d8427ba3d8824852ec0041569191bff4

Gyazo

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This is my material:
https://gyazo.com/9e15070c9a6f1b9afeed8cd339e82a0e

Gyazo

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does anyone have a pointer on how to go with this?

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(also tried dbuffer translucent normal)

obtuse seal Jul 20, 2018, 5:57 PM

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You can mask out all normals pointing straight up to be rid of the big ole square decals

short sorrel Jul 20, 2018, 5:58 PM

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how can i do that?

obtuse seal Jul 20, 2018, 5:59 PM

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Make a separate mask based on your NormalMap where everything that is part of the boot is white, everything else is black

short sorrel Jul 20, 2018, 5:59 PM

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there's no opacity mask in my mnaterial, it's grayed out

obtuse seal Jul 20, 2018, 6:00 PM

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Uh, I haven't worked with masked decals before so I'm not sure on the correct setting for that

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should be a material option to expose it I reckon

short sorrel Jul 20, 2018, 6:01 PM

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but also: this thing isn't DEEP

obtuse seal Jul 20, 2018, 6:01 PM

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Shouldn't be a problem, masking won't introduce any visual depth

short sorrel Jul 20, 2018, 6:02 PM

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the point is that I WANT IT to be deep, but it's not

obtuse seal Jul 20, 2018, 6:02 PM

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I think you will specifically need to change your material's Decal Blend Mode to translucent in order to mask it

short sorrel Jul 20, 2018, 6:02 PM

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right now it looks like a water footprint

obtuse seal Jul 20, 2018, 6:08 PM

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@short sorrel Regarding depth you can use Parallax Occlusion Mapping to give it some apparent depth although I'm not familiar with the technical implementation

indigo jolt Jul 20, 2018, 6:34 PM

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if you want a masked look with decals you have to switch over to Dbuffer type

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you won't lit-rendering in shadow with translucent or additive

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if you keep it always in a lit area, you can almost do some good stuff with translucent, but i wouldn't bother

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just dbuffer

short sorrel Jul 20, 2018, 6:36 PM

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ok, but decal requires translucent, maybe i did misunderstand your point? also, still there's no depth of my footprint

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i want to achieve something like this https://static4.depositphotos.com/1015300/308/i/950/depositphotos_3087820-stock-photo-footprint-in-the-snow.jpg

indigo jolt Jul 20, 2018, 6:42 PM

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oh if you want to do that then just set it to normal

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https://i.gyazo.com/f98aa1ce10cb478b47bc2503693c20ed.png

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the blend mode will always be translucent

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but the DECAL BLEND MODE is the thing we change

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that's the only relevant topic with regard to decals

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for what you're doing use that Normal blend mode and make sure you use an opacity mask to crop out everything around the boot or you'll be affecting things in a square

short sorrel Jul 20, 2018, 6:55 PM

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yes indeed 😃

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however the depth is really disappointing... maybe i need to change my normal map..? my approach seems correct given what you are stating

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i’m trying to find nm like these... https://answers.unrealengine.com/storage/attachments/85187-footprint03.png

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maybe this will help

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but i can’t seem to find them

obtuse seal Jul 20, 2018, 7:22 PM

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A normalmap only provides information on the direction light should bounce per pixel, it does not modify geometry or otherwise create true depth, although it is an important part of selling the effect

cold sorrel Jul 20, 2018, 7:24 PM

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If you want actual depth your only option is POM

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If you are after this classic. http://dougvfx.blogspot.com/2013/07/deep-snow-prints.html

Deep Snow Prints

Spoiler Warning!!!!!!!!!!!!!!!!!! Be aware that the video below shows some footage that would be a spoiler for someone who hasn't played th...

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Is it ok to call TLOU a classic yet? feels like it just came out

indigo jolt Jul 20, 2018, 7:28 PM

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i'm not sure if you can do parallax occlusion mapping with decals or not though

cold sorrel Jul 20, 2018, 7:28 PM

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Sure you can

indigo jolt Jul 20, 2018, 7:28 PM

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i guess they did it in Fallout 4

cold sorrel Jul 20, 2018, 7:28 PM

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Well, you could a year ago, last time I tried it

indigo jolt Jul 20, 2018, 7:28 PM

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i just struggled to make it look right in unreal

cold sorrel Jul 20, 2018, 7:28 PM

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They are finicky as all hell though

indigo jolt Jul 20, 2018, 7:28 PM

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might be personal failing

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i think it's worth doing for huge divots like craters

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not sure i'd advocate it for shallow footsteps

cold sorrel Jul 20, 2018, 7:29 PM

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It's madness from a performance perspective, but that wasn't the question 😄

indigo jolt Jul 20, 2018, 7:29 PM

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if it's as wide/deep as a basketball it's worth

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but otherwise...

cold sorrel Jul 20, 2018, 7:30 PM

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Most of the things in this channel are mad from a performance perspective so it's par for the course

indigo jolt Jul 20, 2018, 7:30 PM

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yeah, i'm not even thinking performance, i just usually cull any solution that isn't going to visually register

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it requires a lot of shape/depth to get much out of POM.

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unless it's like fur

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then it's pretty sick even shallow

short sorrel Jul 20, 2018, 7:32 PM

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so to do a footprint like the image above i need pom?

indigo jolt Jul 20, 2018, 7:33 PM

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no, but feel free to go that far if you're a perfectionist looking for cinematic quality

obtuse seal Jul 20, 2018, 7:33 PM

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didn't the snow in the latest GOW use some vertex displacement and tesselation, that effect is nuts 🤔

indigo jolt Jul 20, 2018, 7:33 PM

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ya that snow was insane

cold sorrel Jul 20, 2018, 7:33 PM

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That's a whoole other ballgame

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Not decals

obtuse seal Jul 20, 2018, 7:34 PM

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Of course it is entirely different though like glad said lol

indigo jolt Jul 20, 2018, 7:34 PM

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i think they might have been using that render-target type terrain offset stuff + mesh emitters?

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i'm not even sure

cold sorrel Jul 20, 2018, 7:35 PM

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Pleh I had to fake that stuff for a static cinematic using VATs a while back. That was tricky enough. Don't even want to think about doing a proper implementation for it

obtuse seal Jul 20, 2018, 7:36 PM

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I'm guessing there's a separate deformation mesh that that projects onto the tesselated snow

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plus some really sharp particle systems to sell all of the snow fluff that gets thrown around

indigo jolt Jul 20, 2018, 7:37 PM

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or you could have 1 million gpu snow particles all set to render on the terrain but offset vertically a bit. then put vector fields on the character's feet

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you try it first tho plz

obtuse seal Jul 20, 2018, 7:37 PM

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kappa

short sorrel Jul 20, 2018, 7:46 PM

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thank you guys 😃

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is there an online resource for things like these?

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not necessarily free

ebon gate Jul 20, 2018, 7:49 PM

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I prefer the viewport from cascade is there a way to change the viewport background in niagara?

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i want to have a black background.

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also in cascade i am able to slow down the time of the viewport in cascade and was wondering how i can do it niagara?

obtuse seal Jul 20, 2018, 7:52 PM

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@ebon gate Took more FOREVER to find it but there's options under the Window panel

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I think, I would check where the settings are but I'm waiting on a source build

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In regards to time adjustment you can change that by setting the timescale on the sequencer scrubber thingy on the bottom

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yeah I'm really good at explaining this kappa

ebon gate Jul 20, 2018, 8:05 PM

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Oh right i see it.

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Preview scene settings

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found the settings for playback speed thanks.

slender tapir Jul 20, 2018, 8:15 PM

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how do i start to do game effects like cokie

cold sorrel Jul 20, 2018, 8:30 PM

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Cokey Li?

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If so, take a course on traditional handdrawn vfx, to learn the drawing and timing. Then learn all the essential realtime vfx techniques. Then you just have to spend a few years practicing that combo.

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Should be doable within a decade or so

indigo jolt Jul 20, 2018, 8:33 PM

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i'll be at least as good as Cokey in no more than 8 years from now tops

cold sorrel Jul 20, 2018, 8:33 PM

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Yeah, but you already know the basics 😄

indigo jolt Jul 20, 2018, 8:33 PM

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lol

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his stuff is intimidating

cold sorrel Jul 20, 2018, 8:33 PM

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Cokey is godtier in his niche

indigo jolt Jul 20, 2018, 8:34 PM

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had no less than 2 job interviews where i was told "do Cokey Li" and showed me his reel

barren raven Jul 20, 2018, 8:34 PM

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Can anyone verify that motion blur for a Niagara system doesn't work by default on a new 4.20 project? Using the visualize motion blur it's easy to see. The motion blur works perfectly in the Niagara content examples, so I feel like there is a project specific setting I'm missing to enable the blur.

indigo jolt Jul 20, 2018, 8:34 PM

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i don't suck, but god it's a painful comparison

obtuse seal Jul 20, 2018, 8:34 PM

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I'll give it a try @barren raven

barren raven Jul 20, 2018, 8:35 PM

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Thank you very much

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It's definitely possible to get working, but can't find whatever project setting that is needed to enable it

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I have the Niagara / Niagara Extras plugin enabled btw, and the default new level is enough to test as it shows blur for other objects there. Going through the project settings one by one comparing to the content examples project until I find it 😄

cold sorrel Jul 20, 2018, 8:35 PM

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Yeah, I kept getting asked about Cokey and ChengGang effects

ebon gate Jul 20, 2018, 8:36 PM

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I have this flickering effect when particle spawns I set the curve to 0 on Opacity in time 0bit it still somehow appears white. https://gyazo.com/54908cfd7b3ebfc1f26bdd7f5da68c21.gif

barren raven Jul 20, 2018, 8:38 PM

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Ok I think I've found the solution

slender tapir Jul 20, 2018, 8:39 PM

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haha ok thanks everyone, is all of that mostly mesh and particles or is there more to it?

ebon gate Jul 20, 2018, 8:39 PM

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oh wait nevermind. i forgot to right click to scroll back to the negative values like in sequencer.

barren raven Jul 20, 2018, 8:40 PM

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📎 Motion_Blur.PNG

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Enabling the "Accurate velocities from Vertex Deformation" checkbox seems to enable motion blur with Niagara

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Double checking now

obtuse seal Jul 20, 2018, 8:40 PM

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What window is that under?

barren raven Jul 20, 2018, 8:40 PM

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Project Settings / Rendering

slender tapir Jul 20, 2018, 8:45 PM

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it looks like ive got a lot of work to do 😄

barren raven Jul 20, 2018, 8:47 PM

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📎 ScreenShot00003.jpg

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Confirmed for me at least

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Phew glad to get to the bottom of it!

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TLDR: If you want motion blur with Niagara, tick the "Accurate velocities from Vertex Deformation" checkbox under Project Settings -> Rendering

ebon gate Jul 20, 2018, 9:28 PM

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where is the orbit module in niagara? is it under some other name?

stone verge Jul 21, 2018, 3:47 AM

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hi i wan your opinion

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i am making a particle pack and sell it for ue4 markeplace and make some money for my game

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should i work on it using cascade or should i make it for niagara?

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what would you do?

ebon gate Jul 21, 2018, 2:01 PM

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I think niagara cos its new and will replace cascade at some point.

cold sorrel Jul 21, 2018, 2:59 PM

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Niagara isn't production ready yet. The only ones buying things for it now are people trying to learn it, I think

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Cascade isn't going away for years

sullen forge Jul 21, 2018, 3:25 PM

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you could do both,and sell the niagara one separately

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people might buy the niagara version to tinker with it and experiment

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that in the case its not too bad for you

ebon gate Jul 21, 2018, 4:11 PM

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is there a module similar to Initial Rotation rate in niagara? I tried using particle.spriterotation in the particle update but that doesnt seem to rotate at a constant rate.

spark latch Jul 21, 2018, 6:37 PM

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I'm having a hard time figuring out how to get a particle to spawn at 0.0 in the niagara timeline

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I want it to only spawn once, with a lifetime of 0.25 at 0.0

short sorrel Jul 21, 2018, 7:26 PM

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so... following up on yesterday discussions i’m making footprints in the snow with POM. At least just for fun. Probably a question that makes not much sense in this group but... how expensive is this? Like, can I use it in my game? 😄

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multiplayer, max 12 concurent

cold sorrel Jul 21, 2018, 7:27 PM

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Then you better fade them away quicklike

short sorrel Jul 21, 2018, 7:28 PM

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what is quick?

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30 secs?

cold sorrel Jul 21, 2018, 7:28 PM

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before you have too many

short sorrel Jul 21, 2018, 7:28 PM

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lol

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what is too many then 😃

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“before the game slows down”

tardy dome Jul 21, 2018, 7:29 PM

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when the cost gets too high 😛

short sorrel Jul 21, 2018, 7:29 PM

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i’m sensing a circular discussion is about to come up 🤣

cold sorrel Jul 21, 2018, 7:30 PM

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12 people running in the same area, 2feet12people2stepspersecond*30seconds =1440 decals.

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If you place that many in your testlevel and test it on target hardware, you'll know

tardy dome Jul 21, 2018, 7:31 PM

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somehow my teamm allways have 1 person standing still tho

cold sorrel Jul 21, 2018, 7:32 PM

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You don't opt for your team 😉

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You opt for the competent players

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And the dickheads who all throw their gasgrenade in the same area... All 64 of them. ptsd twitching

tardy dome Jul 21, 2018, 7:33 PM

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yea, ppl will team up and try too break ur game as much as possible 😛

cold sorrel Jul 21, 2018, 7:33 PM

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Oh yes

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And it all ends up on youtube as "fun glitch compilations".

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Bastards the lot of em

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😄

tardy dome Jul 21, 2018, 7:34 PM

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what if all 12 of us stand on each others head and the bottom person jumps

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this will happen 😛

short sorrel Jul 21, 2018, 7:38 PM

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that’s a good point

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well indeed i can set a time & total count limit

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well indeed i can set a time & total count limit

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but is pom way more expensive than a normal map?

cold sorrel Jul 21, 2018, 7:39 PM

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yes

short sorrel Jul 21, 2018, 7:40 PM

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hm

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damn.

cold sorrel Jul 21, 2018, 7:42 PM

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To be fair that many regular decals still sound very impressive

tardy dome Jul 21, 2018, 7:43 PM

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but footsteps are small so there is that

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hard crusted icy snow doesnt need footsteps 😛

cold sorrel Jul 21, 2018, 7:45 PM

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still 1400 drawcalls on something barely visible

tardy dome Jul 21, 2018, 7:45 PM

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isnt decals auto instanced?

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there was something making em cheap to use

cold sorrel Jul 21, 2018, 7:46 PM

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Perhaps. I haven't looked into them in ages.

tardy dome Jul 21, 2018, 7:49 PM

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i spawned decals on tick once took a while for it to get real bad, and the cost is directly related to their size

cold sorrel Jul 21, 2018, 7:49 PM

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That's just overdraw

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Can't find any info about dynamically spawned decals would auto instance. Do you have a link?

tardy dome Jul 21, 2018, 7:52 PM

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dunno what it was but something made em kinda cheap to use

cold sorrel Jul 21, 2018, 7:54 PM

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right...

short sorrel Jul 21, 2018, 7:54 PM

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decals normal maps or decals pom?

cold sorrel Jul 21, 2018, 7:54 PM

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Either

short sorrel Jul 21, 2018, 7:55 PM

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sorry i meant “something made em kinda cheap”: which ones

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then again knowing what would be helpful 😃

cold sorrel Jul 21, 2018, 7:55 PM

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POM is just a shaderfunction so there would be no difference in the instancing question

tardy dome Jul 21, 2018, 7:55 PM

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deferred

cold sorrel Jul 21, 2018, 7:58 PM

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Well, the docs say "Many Decals can be rendered at once without a large performance decrease" so go nuts

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we don't need more detailed descriptions

tardy dome Jul 21, 2018, 7:59 PM

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where?

short sorrel Jul 21, 2018, 7:59 PM

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lol

cold sorrel Jul 21, 2018, 7:59 PM

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https://docs.unrealengine.com/en-us/Resources/ContentExamples/Decals/1_1

short sorrel Jul 21, 2018, 8:00 PM

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well then if “many” is ok... i can sleep well now

cold sorrel Jul 21, 2018, 8:00 PM

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Exactly!

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Give all 12 players miniguns and let the bulletholes live forever!

tardy dome Jul 21, 2018, 8:01 PM

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not bein able to write my name with bulletholes allways bothers me 😛

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but i knew i read something somewhere decals were made kinda cheap 😛

mortal lily Jul 21, 2018, 8:02 PM

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do note that shader instruction count still is a thing

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esp. with POM iirc

cold sorrel Jul 21, 2018, 8:02 PM

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Yep

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POM will be expensive AF with that many

mortal lily Jul 21, 2018, 8:02 PM

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yup

tardy dome Jul 21, 2018, 8:02 PM

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then again only 1 way to really find out 😛

short sorrel Jul 21, 2018, 8:02 PM

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okok got it

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normal map it is

tardy dome Jul 21, 2018, 8:03 PM

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learn it right by doin it wrong, thats my motto 😛

cold sorrel Jul 21, 2018, 8:04 PM

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"Decals cost similarly to an unshadowed Movable or Stationary light, because they are both applied in a deferred pass. Covering the entire ground with them should have a pretty heavy cost, especially as you look at an angle where you are looking through potentially hundreds of them. GPU costs such as this can be seen with 'profilegpu', so to a performance test. Decals are under PostProcessDeferredDecals."

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That doesn't sound like what I imagined when I read, Many...

tardy dome Jul 21, 2018, 8:06 PM

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the plot thickens 😛

short sorrel Jul 21, 2018, 8:06 PM

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wellwell

cold sorrel Jul 21, 2018, 8:06 PM

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"Decals cost mostly in overdraw, similar to unshadowed dynamic lights or if you placed translucent sheets everywhere."

short sorrel Jul 21, 2018, 8:06 PM

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tomorrow i’ll spawn my pom footsteps ontick event and report back when gpu screams

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sounds like a fun sunday

cold sorrel Jul 21, 2018, 8:07 PM

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The Epic stance on it seems to be, worry about overdraw, not much else, then profile it

short sorrel Jul 21, 2018, 8:07 PM

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i’m way too ignorant to know what overdraw means in practical terms for my footprints

cold sorrel Jul 21, 2018, 8:14 PM

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Let us know! I'm super curious about the drawcalls.

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I mean, 1400 drawcalls would be insane. For comparison the total target drawcall budget for Robo Recall was 1500

short sorrel Jul 21, 2018, 8:21 PM

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i’m not the first one to put footsteps though am i...

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i’ll set a hard limit

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one in time, one total

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my understanding is that anyway decals far from a player are outside the render zone

celest jasper Jul 21, 2018, 10:46 PM

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You are right, you are not the first to put footsteps in his game, but 1400 decals per second is something that not everyone is doing, so the number of people who tested this is pretty low. Also, nobody would test for a raw decal per second number. There is overdraw, different gpu's, the rendering pipeline every engine is using, the material complexity and like you said, if you can cull.

cold sorrel Jul 21, 2018, 11:05 PM

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1400 total. Not per second

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Many people have done it. Many have done it and then cut it due to performance vs visual add

celest jasper Jul 21, 2018, 11:25 PM

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woopsie, sorry for reading not properly ❤

lime agate Jul 22, 2018, 12:04 AM

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Hi! I'm new to vfx, should i start learning Niagara instead of the old system?

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all what can be done in the old sysctem can be done in Niagara at the moment?

ebon gate Jul 22, 2018, 12:54 AM

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@lime agate I'd say learn cascade first then niagara to learn the basics and learn the concept of modules, emitters, Initial modules and multiplier modules etc. I was initially confused with niagara but the knowledge from cascade made things a lot clearer for me.

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this tutorial from Bill Kladis is amazing. it will make you a VFX expert in no time.😉 http://3dmotive.com/series/udk-cascade-beginner-s-guide.html

The web's best game art and 3d modeling tutorials

The web's best 3d modeling tutorials and training videos for popular 3d modeling software including 3ds Max, Maya, ZBrush, UE4, UDK, Mudbox, Unity, ZBrush and more.

lime agate Jul 22, 2018, 1:26 AM

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wow thankyou

ebon gate Jul 22, 2018, 2:41 AM

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By the way does anyone know how to kill the particles on collision in niagara?

obtuse seal Jul 22, 2018, 2:46 AM

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There should be a Particles.IsAlive member or something like that, toggle it in the collision response

short sorrel Jul 22, 2018, 9:38 AM

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@cold sorrel indeed i was not implying i did not get your point, quite the contrary

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i meant: i’m not the first one so with compromises it can be done, i’ll pay more attention to what kind of compromises game have took

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for instance: only the last 10 footsteps per player (that’d be a max of 120 and only if all players are near each other)

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ah plus 2 dogs 🤣

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and thanks for taking the time to help, really appreciate it

celest birch Jul 22, 2018, 10:35 AM

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You could go the route of storing trails into a render target instead

short sorrel Jul 22, 2018, 10:38 AM

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that sounds interesting? what do you mean with that, i.e. not footprints but traces?

celest birch Jul 22, 2018, 10:46 AM

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They would still be footprints. You just draw a footprint "brush" into the render target and have your ground material use it to do displacement or whatever else

analog onyx Jul 22, 2018, 10:49 AM

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I suggest using a render target with indirection texture, that would point to actual footstep texture. There are certain limitations, as if not being able to get overlapping footsteps, but it scales remarkably well for huge number of footsteps and their sources.

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Can integrate it directly into terrain rendering, with all consequent benefits.

near ferry Jul 22, 2018, 10:58 AM

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Can you set the skeletal mesh for a niagara system via bp / code?

short sorrel Jul 22, 2018, 11:25 AM

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@celest birch and @analog onyx these seems very interesting suggestions, given that my game relates to chasing a fugitive and keeping track of all footprints might be very interesting http://www.misultin.com/

Misultin Games - One Step Ahead

One Step Ahead is a multiplayer simulation game where you can choose to play the role of a fugitive, military or a K-9 unit.As a fugitive, stay alive and complete your primary goal. As military, team up with K-9 units to track fugitives down.

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however i'm really ignorant in terms of render targets... will start learning

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still it looks to me that even with render target i'd need to limit the area (cannot cover a 2kmx2km map)

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maybe i could save the footsteps coordinates in an array

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and hide/show them according to the player's position

short sorrel Jul 22, 2018, 1:33 PM

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https://gyazo.com/c9d888c9620084df9c69402502f11f06

Gyazo

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but... POM

mortal lily Jul 22, 2018, 1:39 PM

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POM based decals? oh dear shader instruction count 😛

short sorrel Jul 22, 2018, 1:41 PM

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yeah I know right..

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but how the hell can I get a DEEP footprint instead

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https://gyazo.com/f488f9549c3660dca43e35efbb277e63

Gyazo

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the difference is pretty significant

rapid thistle Jul 23, 2018, 11:06 AM

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Have you tried bump offset instead? It'll be a ton cheaper and might look decent enough

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If not, POM should be fine, a couple of games do it, even on console.

short sorrel Jul 23, 2018, 11:11 AM

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I need to check if you create a bump offset with normals only. Is it much better performance-wise?

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i will def try

spark latch Jul 23, 2018, 2:33 PM

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Has anyone had success with skeletal mesh sampling using Niagara?

ocean hedge Jul 23, 2018, 3:04 PM

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take a look at the content example we just shipped

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the last example has a skinned mesh that you can dig into

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also make sure to look at your log

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if we cannot attach to a skinned mesh or it doesn't have the right flags set, we should warn you in the logs

robust quail Jul 23, 2018, 3:25 PM

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the niagara preview feels like it's running at low fps to me, anyone else notice this?

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claims it's going at 100 like it should but it doesn't look smooth?

obtuse seal Jul 23, 2018, 3:55 PM

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@robust quail I haven't noticed any performance issues with the preview scene personally, does the problem happen in a blank scene, under stress with a lot of particles, etc?

robust quail Jul 23, 2018, 3:55 PM

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it doesn't seem to be a performance issue, since even with 1 million particles it's running at 100 fps

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it just doesn't... feel smooth? idk how to describe the problem

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it looks like how a game locked to 60hz running on a 100hz monitor looks like

obtuse seal Jul 23, 2018, 3:56 PM

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Interesting

robust quail Jul 23, 2018, 3:57 PM

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https://i.imgur.com/JoHev1g.png great

Imgur

obtuse seal Jul 23, 2018, 3:58 PM

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Can't say I would know what causes that, there's probably a profiling stat for the Niagara moviescene

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uh don't know anything about that crash though lol

sullen forge Jul 23, 2018, 3:58 PM

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might be inproper frame pacing

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where your average fps is high, but your frametimes are wobbly

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check stat unitGRAPH

robust quail Jul 23, 2018, 3:59 PM

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is there some way I can bring that up in the niagara window?

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hm

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dunno what's up with the niagara preview window, it looks perfectly smooth in the world

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it's definitely running at lower fps in the preview

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https://i.imgur.com/HWr206k.png

Imgur

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wonder if this is related

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wut the emitter disappears if the source is off screen

obtuse seal Jul 23, 2018, 4:07 PM

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That's how automatic emitter boundaries work, generally speaking

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Here's something I'm curious about. I'm testing out a Niagara DataInterface to add user defined buffers to GPU Emitters. Do I need to manage the lifetime of buffers I create? i.e. I create a new buffer with RHICreateUniformBuffer and then set it to a FShaderUniformBufferParameter member of my DI.

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I'm guessing it should be safe as the buffer RHI gets GC'd with my DI

fair orbit Jul 23, 2018, 4:21 PM

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Hey guys, I've got a question. I have an effect created in this particle editor, let's say it's explosion. is there any way which would let me render this explosion to PNG frames in the editor here?

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📎 unknown.png

ebon gate Jul 23, 2018, 4:44 PM

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In cascade you can use GPU particles for receive events but in niagara when i use receive collision event on gpu particles nothing comes up. am i missing something or is it a limitation in niagara?

robust quail Jul 23, 2018, 4:57 PM

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https://dl.dropboxusercontent.com/s/4yrha5inp38l77z/2018-07-23_18-57-17.mp4 uh

▶ Play video

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is the map get node meant to work?

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I put the emitter in a system so I can put it in the world but now it seems to have made a copy in there and editing the emitter doesn't change the one in the system

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niagara is very confusing

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attempting to edit the system while it's spawned in the world crashes the editor

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aaaaa

obtuse seal Jul 23, 2018, 5:11 PM

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What in tarnation

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@robust quail I don't know why everything is broken for you but it werks on my machine(tm)

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The issue with getting a pin from the Map Get node is particularly concerning, did you resolve that?

robust quail Jul 23, 2018, 5:14 PM

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nope

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it's broken

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have to select an option like "engine" and then use keyboard navigation to go from there

obtuse seal Jul 23, 2018, 5:15 PM

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how odd

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do you have any issues in BP graph editor?

robust quail Jul 23, 2018, 5:17 PM

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that one works mostly flawless

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though the menu where you chose a new parameter class sometimes also jitters left/right

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at least it did in 4.19

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I like how taa makes all my particles have trails

obtuse seal Jul 23, 2018, 5:18 PM

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I haven't had an issue selecting options from a sub-menu even with the early versions of Niagara so I'm assuming it's some long standing issue related to the slate code for the graph behavior

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but if you can replicate it then please send a bug report for it

robust quail Jul 23, 2018, 5:19 PM

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I mean

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I can replicate it by just trying to add a pin to map get

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it simply doesn't work

obtuse seal Jul 23, 2018, 5:20 PM

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How very strange. I would submit a bug report with your systems specs regarding the issue. Do you have an odd resolution monitor?

robust quail Jul 23, 2018, 5:20 PM

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oh

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I figured it out

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the issue happens when the menu goes off screen at the bottom

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if I move it all the way up so it doesn't it works

obtuse seal Jul 23, 2018, 5:20 PM

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good catch, I'll try replicating in a few...

robust quail Jul 23, 2018, 5:21 PM

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it should probably stop somewhere above the bottom of the screen and get a scrollbar instead lol

obtuse seal Jul 23, 2018, 5:22 PM

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@ebon gate To get a collision event you need to have the Collision Query and Generate Collision Event modules in your Particle Update stack, see the example content for reference

robust quail Jul 23, 2018, 5:23 PM

#

is there some way to set approximate culling bounds based on how big you expect it to get so it doesn't disappear instantly?

obtuse seal Jul 23, 2018, 5:24 PM

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@robust quail Trying to get the submenu to flow off of the screen but it repositions to be within bounds, will have to do more testing to see what causes it to overflow the screen boundaries

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@robust quail Regarding particle system boundaries you can assign them under the Emitter Properties module in the Emitter Spawn section of the stack

robust quail Jul 23, 2018, 5:25 PM

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https://dl.dropboxusercontent.com/s/i4dtqlfr4zfddha/2018-07-23_19-24-40.mp4

▶ Play video

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it just goes off screen for me

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then it becomes unclickable

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sometimes it also flickers above and below

obtuse seal Jul 23, 2018, 5:25 PM

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thanks for that info, I'll try that method to see if it overflows

robust quail Jul 23, 2018, 5:26 PM

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https://i.imgur.com/BSrmtZD.png what would be editing the bounds?

Imgur

obtuse seal Jul 23, 2018, 5:27 PM

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You set fixed bounds to true and then manually set a bounding box where the Emitter is relevant and not culled

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it defaults to a 100x100x100 cube

robust quail Jul 23, 2018, 5:27 PM

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it appears to work without checking the box so I'm confused what the box is for

obtuse seal Jul 23, 2018, 5:28 PM

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uh

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that sounds like a potential bug lol

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I'll look into it

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should have to set the bvar to enable fixed bounds

robust quail Jul 23, 2018, 5:28 PM

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I mean the box doesn't say it's to use these bounds but to prevent editing the bounds

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(whatever that means)

obtuse seal Jul 23, 2018, 5:29 PM

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Uh... shows what I know

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I assume without fixed bounds the engine checks whether an emitter is relevant if the source is within the camera frustrum

robust quail Jul 23, 2018, 5:30 PM

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are you supposed to add the emitter to a system to spawn it?

obtuse seal Jul 23, 2018, 5:30 PM

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Yes Emitters must be part of a System to be in the game world

robust quail Jul 23, 2018, 5:30 PM

#

right

#

but if I then add new modules to the emitter asset

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it doesn't update the copy in the system

obtuse seal Jul 23, 2018, 5:30 PM

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You have to hit the Apply button and probably recompile the system as well

#

also regarding getting the Map Get submenu to overflow I can't make it work even by squishing my window or positioning it between the boundary of two monitors, @robust quail what resolution is the monitor your Niagara editor window is on?

robust quail Jul 23, 2018, 5:31 PM

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oh I just assumed clicking save would do all of those things

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3440x1440

obtuse seal Jul 23, 2018, 5:32 PM

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wellthere'syourproblem.wav

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Yeah I'm guessing there's a logic issue with determining the bounds for the submenu when it's created

robust quail Jul 23, 2018, 5:32 PM

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just using the default 1:1 dpi scale

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so no fancy stuff going on

#

what's the giant sphere I can see in the background when bounds view is enabled? https://i.imgur.com/YguaGfS.png

Imgur

obtuse seal Jul 23, 2018, 5:34 PM

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good question, I have no idea

robust quail Jul 23, 2018, 5:34 PM

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maybe particle sim bounds?

obtuse seal Jul 23, 2018, 5:35 PM

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relevance boundaries or some such

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I haven't played around with it yet so just a guess

robust quail Jul 23, 2018, 5:35 PM

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change value

#

ctrl z

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emitter disappears

#

lol

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ah compile fixed it

obtuse seal Jul 23, 2018, 5:36 PM

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careful with walking back through the edit history, there's probably still a good few crashes related to it

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e.g. save often :)

robust quail Jul 23, 2018, 5:37 PM

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yeah

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got into a habit of saving like every 5 seconds when working with unreal

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what's up with the wire colors randomly changing

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https://i.imgur.com/LfNz6KX.png

Imgur

obtuse seal Jul 23, 2018, 5:42 PM

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It's just how abstraction works in Niagara Graph right now

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Multiply node isn't type dependent, you can plug any type into it

robust quail Jul 23, 2018, 5:42 PM

#

ah

obtuse seal Jul 23, 2018, 5:42 PM

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so the type it outputs is called a NiagaraNumeric

robust quail Jul 23, 2018, 5:42 PM

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so it's kinda like the material editor

obtuse seal Jul 23, 2018, 5:42 PM

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you can actually right click the pin exiting the multiply node and manually assign what type goes out

robust quail Jul 23, 2018, 5:42 PM

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huh

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it only gives me break link options

obtuse seal Jul 23, 2018, 5:42 PM

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I believe it's planned sometime that the pins will dynamically change to represent what's actually getting passed through

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yeah you have to break all links first I think

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it's a little buggy anyway and not required but worth noting

robust quail Jul 23, 2018, 5:43 PM

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ah yeah it works with nothing connected

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interesting

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https://i.imgur.com/yNvhbMx.png

Imgur

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these 2 background colors could really use more contrast between them

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what it crashed by itself without me doing anything

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just in the background lol

obtuse seal Jul 23, 2018, 6:03 PM

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Regarding the issue with Map Get node's submenu to add a pin overflowing I'm guessing it's an issue underlying in SExpanderArrow but I don't write Slate so I've no clue where the geometry bounds get verified

#

moreover it likely stems from issues supporting high resolution displays that would affect everything that uses the existing graph code

ocean hedge Jul 23, 2018, 6:16 PM

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I'm going to get some of our QA guys to try and reproduce the problems above

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@robust quail if we need it, mind if we DM you for more info?

robust quail Jul 23, 2018, 6:17 PM

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sure

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you're right it's affecting more menus

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https://i.imgur.com/Hffbmua.png this one is broken aswell

Imgur

#

https://dl.dropboxusercontent.com/s/vtp0vhigdm6daos/2018-07-23_20-22-37.mp4 pls

▶ Play video

ocean hedge Jul 23, 2018, 6:23 PM

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@obtuse seal If you create the resource, make sure it is traceable back to a UProperty on a UObject. Otherwise, it could leak.

obtuse seal Jul 23, 2018, 6:24 PM

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@ocean hedge Good call, I hadn't marked the FShaderUniformBufferParameter as a UProperty 👍

#

Oh and thanks Wyeth for adding a Slerp function, I needed that but couldn't find any docs on writing it in hlsl

obtuse seal Jul 23, 2018, 7:30 PM

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I was looking through the VM binding for functions in Niagara DIs and I see you can instantiate FNiagaraTypeDefinitions with a UScriptStruct, is this part of planned support for an eventual arbitrary struct type in Niagara?

robust quail Jul 23, 2018, 7:35 PM

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how come the make [thing] nodes in niagara are so much larger than similar ones would be in bp? https://i.imgur.com/aI2yTcG.png

Imgur

obtuse seal Jul 23, 2018, 7:35 PM

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It's a Conversion node unique to Niagara

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you can drag the pins manually to convert types however you like

robust quail Jul 23, 2018, 7:36 PM

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huh

obtuse seal Jul 23, 2018, 7:36 PM

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but yeah making a new type in place uses the Convert node which is huge

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you can click the little wrench icon to squish it a bit lol

boreal gull Jul 23, 2018, 7:36 PM

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woah what a node.

robust quail Jul 23, 2018, 7:37 PM

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oh wtf

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https://i.imgur.com/lH7aGhp.png

Imgur

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so it's some kinda advanced split/regroup node https://i.imgur.com/aT3hTAg.png

Imgur

boreal gull Jul 23, 2018, 7:38 PM

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if they uh "port" that to BP that'd probably make a PR I've been working on moot.

obtuse seal Jul 23, 2018, 7:38 PM

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some other peeps working with Niagara were interested in seeing that in BP too

robust quail Jul 23, 2018, 7:39 PM

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how come the spawn burst module needs to go in emitter update instead of emitter spawn

obtuse seal Jul 23, 2018, 7:39 PM

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it just werks that way

robust quail Jul 23, 2018, 7:39 PM

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it's kinda strange tho because you'd only want that to do stuff once right

obtuse seal Jul 23, 2018, 7:39 PM

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I couldn't tell you the technical reason

#

spawn burst can happen multiple times, for instance every time the particle system loops

#

so it logically must be in Emitter update durr

robust quail Jul 23, 2018, 7:39 PM

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hm

obtuse seal Jul 23, 2018, 7:40 PM

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you just set the max loops to 1 in your emitter to prevent the burst from looping

robust quail Jul 23, 2018, 7:41 PM

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I keep getting things stuck highlighted https://i.imgur.com/2vdNlMU.png

Imgur

obtuse seal Jul 23, 2018, 7:41 PM

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yeah there's a bug with highlighting not fixing

#

happens with the exec pin "strings" pretty often

robust quail Jul 23, 2018, 7:50 PM

#

am I missing an obvious way to open the emitter asset from a system?

#

the way you can change things in the system without it indicating you changed it from the emitter defaults in any way is probably going to lead to a lot of confusion

ocean hedge Jul 23, 2018, 7:53 PM

#

the green arrow next to the changed value is the indicator

#

we'll probably be moving to a different coloration of the field itself, but that is much harder to implement

#

just right click on the header and pick the open source emitter from menu

robust quail Jul 23, 2018, 7:55 PM

#

the arrow seems to indicate that it was changed from the module defaults

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not that it was changed from the values set in the emitter asset

ocean hedge Jul 23, 2018, 7:55 PM

#

there are two arrows

robust quail Jul 23, 2018, 7:55 PM

#

oh shit I didn't notice

#

yeah

#

nvm that then

#

ah yeah

#

there wasn't anything indicating right clicking the name would do something so I didn't try that

ocean hedge Jul 23, 2018, 7:57 PM

#

we should probably do a dropdown icon or something to indicate that there is a right-click menu

#

we considered something like the blueprint parent text for a bit, but felt that was too heavy

#

maybe just a hotkey icon on the header

robust quail Jul 23, 2018, 7:59 PM

#

how come the preview viewport on an emitter asset uses the normal right click / wasd navation while the one for the system seems to be using some kind of orbit controls

#

or is that something I somehow toggled without noticing

obtuse seal Jul 23, 2018, 8:02 PM

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@robust quail You can toggle orbit controls under the dropdown arrow in the *preview viewport

robust quail Jul 23, 2018, 8:02 PM

#

huh

#

oh found it

#

definitely didn't change this though

#

it must have been this way before

#

maybe there could be some max width for how wide the properties panel becomes automatically

#

because the default looks like this on my monitor every time I open a niagara thing https://i.imgur.com/ZpWXi0H.png

Imgur

#

see why I didn't notice those arrows to revert things before

ocean hedge Jul 23, 2018, 8:08 PM

#

yeah, that makes sense

#

it's set up for multi selection

#

although most people haven't gotten to that use case yet

#

but I definitely take your point

robust quail Jul 23, 2018, 8:09 PM

#

the panel is a lot more usable after changing it to be this wide https://i.imgur.com/2YZsJ4v.png

Imgur

#

does compiling a niagara module optimize out unnecessary math like * 1 or + 0?

ocean hedge Jul 23, 2018, 8:17 PM

#

yep

robust quail Jul 23, 2018, 8:17 PM

#

nice

ocean hedge Jul 23, 2018, 8:17 PM

#

the system still "hard codes" ints, bools, and enums for just that reason

#

you can examine the hlsl source in the Generated Code Tab

robust quail Jul 23, 2018, 8:18 PM

#

so if you got a thing like this, assuming everything is left at defaults, the last 2 operations get removed? https://i.imgur.com/PG4Ny7I.png

Imgur

ocean hedge Jul 23, 2018, 8:19 PM

#

no

#

we treat any float-based variables as "shader constants" and they are not yet optimized out

#

this makes tweaking variables much more responsive

#

we are investigating having a mode that bakes any non-user/non-engine variables as hard-coded values during cook

#

so that we can more aggressively cull out redundant/dead code

#

but for now we treat ints/bools/enums the same way that the material editor treats static switches

#

so "if" on a value equalling an enum will cause the final assembly to only select the matching path

#

sorry for the confusion

robust quail Jul 23, 2018, 8:23 PM

#

interesting

#

hm there's no entry for emitter update script in the generated code tab

#

does it all get combined into system update?

ocean hedge Jul 23, 2018, 8:24 PM

#

it's a special case, they all get baked into the system update right now

#

or system spawn

robust quail Jul 23, 2018, 8:29 PM

#

definitely makes sense to only consider optimizing it during cook though

indigo jolt Jul 24, 2018, 1:09 AM

#

does anyone know what would prevent Static Mesh Morph targets from doing more than about 50% of the overall morph target movement?

#

it's nuts, i try to squash this pyramidal shape down to basically a pancake and instead it only gets half way there

fresh harness Jul 24, 2018, 1:15 AM

#

@indigo jolt Did you change the scale of it in Editor?

#

Not via BP or C++

indigo jolt Jul 24, 2018, 1:23 AM

#

hmmm the initial scale changed to 0.75

#

just changed that back to 1.0 and not really seeing a difference tho

#

i'm wondering if it's because i did things in reverse of normal

#

i've had success before

#

but normally it's like "small shape to large shape"

#

in this one i'm trying to go from big to small

#

maybe it doesn't like to go "inward"?

#

mmmm nvm nothing i'm doing is working right

#

gonna try messing with overall scale in 3d max before export

#

other successful things i've done before were smaller

fresh harness Jul 24, 2018, 1:50 AM

#

@indigo jolt Dang, sorry. I haven't messed much with morph targets, but I have seen similarly strange problems with a few other animation-related things when something's scale is changed only in the editor.

Edit: I just did a test. Created a huge cube with a point extruded from the top so it's like a pyramid. Scale was twice the size of the default FPS map. Added a morph key to it that shrunk it down flat and scaled to 100th of the original. Have it morphing between the two shapes via timeline in BP and seems to work perfectly fine in 4.20.

ebon gate Jul 24, 2018, 2:36 AM

#

Is there a way to expose nuagara VFX parameters so that I can change them via BP?

near ferry Jul 24, 2018, 8:13 AM

#

@ebon gate Also interested in this. Haven't tested it myself but there are some functions called SetNiagaraVariable (Type). Unfortunately it's missing meshes which was what I wanted. The one for setting actors currently does nothing. You can have a look over here: http://api.unrealengine.com/INT/BlueprintAPI/Niagara/

Niagara

short sorrel Jul 24, 2018, 8:28 AM

#

All, still fighting with footprints in the snow 😃 it's a MP game which unfortunately means that it's easy to go over budget with effects, as they apply also to contendants.

#

Has anyone tried this? looks real nice but I'd be interested in guru's opinions 😃 https://www.raywenderlich.com/196937/creating-snow-trails-in-unreal-engine-4

Ray Wenderlich

Tommy Tran

Creating Snow Trails in Unreal Engine 4 | Ray Wenderlich

In this Unreal Engine 4 tutorial, you will learn how to create deformable snow trails using a scene capture and render targets

fading void Jul 24, 2018, 12:03 PM

#

ok problem

#

I have niagara system

#

I want to externally tell this system to spawn EXACTLY one particle

#

and then every time I press some button (input) I want this system to spawn another particle

#

but there seems not be any event handling for spawning ;s

ocean hedge Jul 24, 2018, 1:50 PM

#

@ebon gate Make them User parameters. There is a Blueprint node for setting User parameters on a Niagara component.

#

@fading void The simplest suggestion I can make is to have a user SpawnCount variable and as needed set that variable to 1 for a frame. Have a module that looks at that variable and creates an appropriate SpawnInfo in its emitter update script. You'll then need to set it to zero in the next frame. We'll be looking at better ways to drive this stuff externally in future releases.

#

you'll be able to set that user variable in BP as indicated in the previous reply

fading void Jul 24, 2018, 1:55 PM

#

@ocean hedge hey thanks for reply 😃

#

@ocean hedge one more question though. Do you guys plan to expose particle event into BP/Code ? like collision events, location, so external systems can use those events.
And the other way around, will external systems be able influence niagara events ?

ocean hedge Jul 24, 2018, 2:31 PM

#

We are investigating it. It is usually a bad idea for game logic to depend on particle system simulation results, but if you wanted to play sound effects or do other aesthetic work I can understand wanting more information. Right now we have DataInterfaces, which allows users to inject completely custom code into the simulation. For instance, you could call a data interface function within your system that caused audio to play. Today most of the data interfaces are there to bring data into the sim, but there's no reason why it couldn't also go out.

#

We may also do things like the previously mentioned spawn event, which has a lot of solid use cases.

obtuse seal Jul 24, 2018, 2:36 PM

#

The potential for massively complex particle sims that aggregate data from everything is quite enticing :)

fading void Jul 24, 2018, 3:00 PM

#

@ocean hedge thanks. Quite understsable you don't want to drive game logic trough particles, I was thinking more in terms, create particle system which spawn tracer (as mesh bullet), and then when that bullet collide spawn another system with hit effect. It's purerly cosmetic.

Guess i could do it from within one system, but idk how maintanable it would be.

ocean hedge Jul 24, 2018, 3:00 PM

#

gotcha

#

there's another complexity that I haven't mentioned yet... latency due to GPU pipelining

#

for any GPU particle system, you may be several frames behind the game thread for rendering

#

any communication from the GPU back to the CPU (which we have to be very careful about coding because it can introduce horrible stalls if not done properly) will inevitably have to be latent by how deep the rendering pipeline is

#

I think Cascade avoided this issue entirely

#

I"m not sure that Niagara can, although any efforts on this front will likely be staged CPU first then GPU

#

for CPU-side effects, though, this problem largely doesn't exist

#

you just have to be careful about thread-safety as the particles are simulating on worker threads, not the game thread

#

just trying to give you guys some insight into our thought process here

obtuse seal Jul 24, 2018, 3:07 PM

#

Can the VM sim systems run a few frames behind the game thread or is that work done in sync?

ocean hedge Jul 24, 2018, 3:07 PM

#

we're not allowing it to be latent right now

#

some of our optimizations will include pushing any simulation that doesn't need updated data from the game thread to sim as early in the game frame as possible

#

depending on bone sockets, skinned meshes, other object transforms/etc inevitably push back when we can fire off the sim

obtuse seal Jul 24, 2018, 3:12 PM

#

Ah that's interesting, so I'm guessing there's a lot of bouncing between game thread and sim thread for systems polling any UObject info then?

ocean hedge Jul 24, 2018, 3:13 PM

#

right now we run about the same time that physics runs (i.e. after the game thread has done all its major work for transform updates)

#

this is really late in the frame and since we make the frame wait unti l we are done, it can slow down the overall game frame

#

optimizations like the ones mentioned above are more fine-grained resolution, allowing us to kick off data much earlier in the game frame

fading void Jul 24, 2018, 3:15 PM

#

ok there is UNiagaraDataInterfaceCurveBase > where can I find it, in editor ? I'm totally at loss where to look for it

ocean hedge Jul 24, 2018, 3:16 PM

#

right now, we can just pull the data we need off the game objects, but in the optimized scheme above, we'll need to push data into something like a command buffer

obtuse seal Jul 24, 2018, 3:16 PM

#

@fading void The DataInterface stuff is just for Niagara Scripts/Emitters/Sims so it's contained within one of the above

ocean hedge Jul 24, 2018, 3:17 PM

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@fading void it is an abstract base class, not directly instantiable inside the editor, found at Engine/Plugins/FX/Niagara/Source/Niagara/Classes/NiagaraDataInterfaceCurve.h in the depot

fading void Jul 24, 2018, 3:17 PM

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yeap I found the code, I just don't understand where it is used in editor (;

ocean hedge Jul 24, 2018, 3:17 PM

#

ah

#

it is just there to share some implementation details between sub-classes

#

the instanceable ones are NiagaraDataInterfaceColorCurve, VectorCurve, etc

#

one class per data type that you might interpolate

obtuse seal Jul 24, 2018, 3:19 PM

#

A question I'd like to throw in @ocean hedge , load-balanced sims are just an idea at this point in time but what use cases would be suitable for if/when implemented?

ocean hedge Jul 24, 2018, 3:19 PM

#

@obtuse seal that is a super thorny question

obtuse seal Jul 24, 2018, 3:19 PM

#

hahahah

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I was mostly curious where one might see it suitable for usage, as personally I couldn't think of an example

ocean hedge Jul 24, 2018, 3:20 PM

#

in a perfect world the simulator would know that the game is GPU or CPU bound and could simulate on the one with the most bandwidth for any given frame, copying data around as necessary

#

sadly, this perfect world is impossible due to the GPU latency I mentioned before

obtuse seal Jul 24, 2018, 3:21 PM

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I expected as much

ocean hedge Jul 24, 2018, 3:21 PM

#

so that puts us in an alternative world where we might have two versions of the sim

#

i.e. a particle will live and die in whatever mode it was spawned in

fading void Jul 24, 2018, 3:22 PM

#

aa thanks, found others

ocean hedge Jul 24, 2018, 3:22 PM

#

but we might decide based on historical data to instead bias all future particles to be spawned on the alternate mode

obtuse seal Jul 24, 2018, 3:23 PM

#

Good to know the thoughts behind this load-balanced mode 👍

ocean hedge Jul 24, 2018, 3:23 PM

#

so over time, it tries to balance out the load

#

to be honest, this is more theory than practice

#

I'm not sure that the "juice is worth the squeeze" here, given the other optimization avenues we have in front of us

obtuse seal Jul 24, 2018, 3:24 PM

#

I was wondering whether you would say that yourself haha

#

I had guessed that it would be quite difficult to implement a load-balancing mode given the other potential optimizations as you stated

ocean hedge Jul 24, 2018, 3:26 PM

#

another, probably easier mode is to compile the script for both cases

#

then, given that most systems live and die in very short time spans, each system instance would be put in one bucket or the other

#

that might have some legs, but it would still be lower priority than other optimizations

obtuse seal Jul 24, 2018, 3:31 PM

#

@ocean hedge Another question I have, I'm working on a boid flocking implementation and was curious how much overhead is incurred using events to synchronize information between all particles in a system

ocean hedge Jul 24, 2018, 3:31 PM

#

it's pretty high

#

we intend to add the ability to query by particle id

obtuse seal Jul 24, 2018, 3:32 PM

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It's a very general question but I ask this because I'm curious about whether it would be possible to expose all particle params as accessible by index

#

oh and there it is ok 👍

#

haha that resolves it

ocean hedge Jul 24, 2018, 3:33 PM

#

if you look at the code that we generate, all the data is sitting there attached in a buffer... you just need the right offsets to access it

#

you just need some sort of data structure to spatially organize the particles

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so you could iterate over all the ones within a certain distance

obtuse seal Jul 24, 2018, 3:34 PM

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I had briefly looked into some implementations and for large numbers it was apparently more efficient to just iterate over all members although I would certainly be doing some profiling myself at that stage

ocean hedge Jul 24, 2018, 3:37 PM

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for you brave souls that want to work with the latest and greatest, the team is currently working out of Dev-Niagara.. expect some volatility, but also yummy goodness like the ability to sample from 2d textures...

obtuse seal Jul 24, 2018, 3:38 PM

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The texture sampling DI is coming along nicely by the way 👍

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I should have a pull request up for my render target DI soon, I will just be copying the implementation provided in the texture DI as it looks much cleaner 🤓

ocean hedge Jul 24, 2018, 3:39 PM

#

I'm actually working on something similar at the moment for approximating volume textures

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with a data interface that lets you read/write to them directly

obtuse seal Jul 24, 2018, 3:41 PM

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Interesting, how do you propose the handle the writeback to (I'm guessing a texture3d)?

ocean hedge Jul 24, 2018, 3:41 PM

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the engine doesn't support 3d textures right now

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at least not dynamic ones

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so it is using atlased texture2d's

obtuse seal Jul 24, 2018, 3:41 PM

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So you average from a texture array then I suppose

#

right

ocean hedge Jul 24, 2018, 3:42 PM

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trying to cover as many platforms as possible with the technique

obtuse seal Jul 24, 2018, 3:42 PM

#

good point

ocean hedge Jul 24, 2018, 3:42 PM

#

it will hopefully show up in the branch in a few days

#

but I expect you guys will be able to come up with crazy fun stuff to do with it

obtuse seal Jul 24, 2018, 3:43 PM

#

Do you create a UAV resource binding for getting data in and out, or otherwise how is read write handled? 🤔

ocean hedge Jul 24, 2018, 3:43 PM

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there's a read and write texture that are swapped

#

can't get that super-fast hardware texture sampling without it

#

RWTexture2D doesn't let you use samplers, just direct indexing

obtuse seal Jul 24, 2018, 3:44 PM

#

Interesting, I need to become more familiar with these optimizations

ocean hedge Jul 24, 2018, 3:45 PM

#

but yeah, bind one tex as a UAV to read and the other as a buffer and write with direct indexing

obtuse seal Jul 24, 2018, 3:46 PM

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is texture UAV binding implemented yet?

#

I had looked into it but it appeared that the necessary flag to pass through on creating it wasn't exposed

#

Likely I misunderstand the proper method to do it

#

in any case I will sift over the new code as soon as it's up on the repo 🤓

ocean hedge Jul 24, 2018, 3:48 PM

#

still working on it

#

will have to create the textures myself with proper bindings

#

http://shaderbits.com/blog/authoring-pseudo-volume-textures for more info on the overall approach

Authoring Pseudo Volume Textures

This post is the second part in a series leading up to building custom volumetric effects inside of UE4. The previous post went over ways to make subUV or volume textures tile seamlessly and that will be used at the end of this post:

Part 1: http://shaderbits.com/blog/tili...

#

by Epic's resident Wizard, Ryan Brucks

obtuse seal Jul 24, 2018, 3:49 PM

#

I had a 50/50 bet this would be built off of Ryan Brucks work lol

#

very nice then, I had been wanting to try replicating the cloud volumes effect

viral wadi Jul 24, 2018, 4:43 PM

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@robust quail The lower frame rate you're seeing in the editor window is due to the fact that we sim at a constant fixed 30fps in order to make scrubbing and seeking work consistently and performantly. In the future we'll probably link this value to the frame rate selected in the sequencer control in the emitter and system editor that way you can configure it yourself.

obtuse seal Jul 24, 2018, 5:13 PM

#

Where would one find the source code for generic util nodes in Niagara, specifically the Execution Index node?

indigo jolt Jul 24, 2018, 5:25 PM

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@fresh harness just an update on the static mesh morph target problem - i switched from Max 2014 (which i've used before successfully for static mesh morph targets) over to Max 2012, now it works perfectly again

#

totally unclear what the cause was

#

starting to really want a newer max

obtuse seal Jul 24, 2018, 5:43 PM

#

argh finally found it under NiagaraEditorCommon

#

retrospectively that makes sense for it to be there 🤔

mortal jacinth Jul 24, 2018, 7:14 PM

#

https://gyazo.com/5e7212c18953678766ac969b3ffddbbe
anyone know how to make the particle effect constant and faster? havent really done particles before

Gyazo

▶ Play video

obtuse seal Jul 24, 2018, 7:14 PM

#

crank up that spawn rate

mortal jacinth Jul 24, 2018, 7:15 PM

#

on "Constant" or?

obtuse seal Jul 24, 2018, 7:15 PM

#

well to get it to persist longer you need your particles to live longer, so you will be increasing the lifetime. To get it to go faster you need to increase the spawn rate

mortal jacinth Jul 24, 2018, 7:16 PM

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i just need it faster

#

as its the gun shot

#

is it that?

📎 unknown.png

obtuse seal Jul 24, 2018, 7:16 PM

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Yes that's spawn rate

#

but if you want to increase the "speed" of the particle you need to give it some more velocity

mortal jacinth Jul 24, 2018, 7:18 PM

#

im increasing the velocity doesnt seem to be respawning faster

obtuse seal Jul 24, 2018, 7:19 PM

#

Respawn rate is controlled by the spawn rate number you posted earlier, bigger number = more spawns (specifically it is the number of particles spawned per second)

mortal jacinth Jul 24, 2018, 7:27 PM

#

thanks

mortal jacinth Jul 24, 2018, 8:03 PM

#

How would I go abouts adding water splash when shooting at water?

obtuse seal Jul 24, 2018, 8:19 PM

#

@mortal jacinth Everytime you shoot you do a linetrace, from the hit result of the linetrace you check if you hit a water body or water surface and if so then spawn a water splash effect at the relevant hit location

mortal jacinth Jul 24, 2018, 8:21 PM

#

is there any tutorials

#

im new to vfx stuff

tiny river Jul 24, 2018, 8:40 PM

#

Any Houdini artists here that would be up for a paid tutoring session?

ocean hedge Jul 24, 2018, 8:54 PM

#

speaking of live streams, @strong carbon will be doing a livestream this Thursday at around 1:30pm EDT. The focus will be on the new Niagara Content Examples map and Niagara's capabilities

ebon gate Jul 24, 2018, 9:00 PM

#

@ocean hedge Just saw your message on exposing parameters. I was just wondering is there a way to set the default values for those parameters to preview the particles? Exposing them makes it difficult to preview what it will look like.

ocean hedge Jul 24, 2018, 9:04 PM

#

@ebon gate may have lost the train of though on that question. Are you referring to default values for module variables or default values for User variables... or something else?

ebon gate Jul 24, 2018, 9:05 PM

#

for user variables

ocean hedge Jul 24, 2018, 9:10 PM

#

you can set them in the UI

#

📎 unknown.png

#

for example ^

obtuse seal Jul 24, 2018, 9:11 PM

#

It would be nice to be able to assign default user vars in the Emitter stage

ocean hedge Jul 24, 2018, 9:13 PM

#

I see

#

that's something we could add if people wanted

#

ironically, you could do something similar when defining the User variable in a module

ebon gate Jul 24, 2018, 9:13 PM

#

Oh right in the system not in the emitter. i was doing it in the emitter.😆

obtuse seal Jul 24, 2018, 9:13 PM

#

interesting

#

Yes it would be very nice to be able to assign default user vars for Emitters

ocean hedge Jul 24, 2018, 9:14 PM

#

our original thoughts were that you'd only need user variables to expose specific things to blueprints or for the level artist to tweak

#

they were the way to connect up systems to the world

#

if they were also shown in emitters, what would you expect to happen if you had two of the same emitter in the system?

#

they would both point to the same user variable?

#

or should they each get their own?

obtuse seal Jul 24, 2018, 9:17 PM

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There should be unique User vars for each Emitter instance, I think. If I make a generic explosion Emitter with a radius property that is a User var, then when that emitter gets collated into some cluster-bomb System it should be possible to assign multiple explosion radii

ebon gate Jul 24, 2018, 9:17 PM

#

ok im starting to get the gist of the process. Expose the parameters in the system and not in the Emitter and then change the variable in the BP using this:

📎 7d547cc4ca6181def048a94bd1c1b331.png

ocean hedge Jul 24, 2018, 9:18 PM

#

yep

ebon gate Jul 24, 2018, 9:19 PM

#

niagara truly is flexible. Its amazing! 😁

#

ok im starting to get a clear picture of how niagara works. I need to figure out the module scripting side. is there a documentation on this?

obtuse seal Jul 24, 2018, 9:28 PM

#

@ebon gate I haven't read over it myself but there's some docs here https://docs.unrealengine.com/en-us/Engine/Niagara

ebon gate Jul 24, 2018, 9:30 PM

#

I've been through all of those guides such as setting up niagara, emitters and add modules. I'm thinking of making my own modules via node graph.

ocean hedge Jul 24, 2018, 9:30 PM

#

https://www.youtube.com/watch?v=mNPYdfRVPtM

YouTube

Unreal Engine

Programmable VFX with Unreal Engine's Niagara | GDC 2018 | Unreal ...

Join us for a first look at Epic Games' new Unreal Engine VFX editor, Niagara. This new suite of tools is built from the ground up to provide unprecedented p...

▶ Play video

obtuse seal Jul 24, 2018, 9:30 PM

#

worth watching the gdc talk too 🤓

ebon gate Jul 24, 2018, 9:31 PM

#

Cool! Will do. Thanks for the help @ocean hedge and @obtuse seal 🤓

ocean hedge Jul 24, 2018, 9:32 PM

#

https://twitter.com/cannabis_cod3r

ash oakenfold (@cannabis_cod3r)

pursuing the dream of making weird things full-time | building stuff with ue4 niagara

Tweets

46

Followers

104

#

lots of good tutorials ^

#

@obtuse seal has some good stuff on his blog

obtuse seal Jul 24, 2018, 9:33 PM

#

Really outdated tut on sampling vector fields which is still WIP lol https://unrealingens.wordpress.com/2018/05/30/exploring-niagara-pre-release-part-1/

Unreal Ingens

Nicholas Goldstein

Exploring Niagara Pre-Release! [Part 1]

Unreal Engine’s new VFX module Niagara has been on Epic’s roadmap for a few years but following Epic’s GDC presentation on Niagara in March, this new system is quickly moving towa…

#

But it does go over a lot of elements of Niagara so good practice familiarizing yourself with a lot of it

#

still need to do a blogpost on other important bits like debugging with Attribute Spreadsheet

ebon gate Jul 24, 2018, 9:35 PM

#

cool! will check both after watching video.

past osprey Jul 25, 2018, 2:24 AM

#

shouldnt this be changing the color? https://gyazo.com/a16a48f1cc970a46aac0d20faef87539

Gyazo

nocturne isle Jul 25, 2018, 2:34 AM

#

it won't work if your texture is black

past osprey Jul 25, 2018, 2:43 AM

#

Thanks

cold sorrel Jul 25, 2018, 12:31 PM

#

@mortal jacinth You can go wtih traditional sprites (of which there are millions of tutorials) or meshbased splashes.

#

https://www.sidefx.com/tutorials/vat-paintsplat-houdini-for-games/

VAT Paintsplat! // Houdini for Games | SideFX

In this tutorial, I'll show how to create a Paintsplat projectile in Unreal Engine 4. I'll take you through the creation of Vertex Animation Texture splashes as well as creating a decal based on baking a FLIP splat. We will start with an empty Houdini scene and finish with a ...

#

Or the slightly older way of doing it: https://www.sidefx.com/tutorials/splashmesh-houdini-for-games/

SplashMesh! // Houdini for Games | SideFX

Create a nice and thick mudsplash in Unreal Engine 4, using a FLIP tank in Houdini. Literally go from an empty scene, set up your FLIP tank, throw a rock down (it's really just a deformed sphere) and then reduce it to the barebones shape and export that single frame of geo in...

mortal jacinth Jul 25, 2018, 12:33 PM

#

Thanks

#

Does that work for when i shoot water?

#

the splash comes up?

cold sorrel Jul 25, 2018, 12:34 PM

#

Hmm

#

You should probably stick to sprites

#

If that's the question.

#

Yes,

#

The direction is based on the blueprint you spawn the effect with

#

the tutorials I linled where more about the creation of the effect, but I believe they may be a bit too advanced.

mortal jacinth Jul 25, 2018, 12:36 PM

#

Looking at that tho, just looks like the gun would always shoot water splash lol

cold sorrel Jul 25, 2018, 12:36 PM

#

Yes...

#

Nevermind I posted 😃

frail sail Jul 25, 2018, 2:02 PM

#

any good resources for making a bullet trail effect like in Fortnite?

#

do you guys think it's particle effects or just a cylinder mesh with a material?

solid stream Jul 25, 2018, 2:02 PM

#

how about ribbons @frail sail ?

frail sail Jul 25, 2018, 2:03 PM

#

maybe

#

thing is, fortnite's shoots are hitscan (except for some) but the effect still gives the idea that there was a bullet being fired while also matching the hitscan pattern of the shot

#

a very fast particle with ribbon could work

solid stream Jul 25, 2018, 2:05 PM

#

havent really paid attention to it while playing, but I'd say particle ribbon yeah

sullen forge Jul 25, 2018, 2:05 PM

#

no it wouldnt

#

ribbons dont work so well

solid stream Jul 25, 2018, 2:05 PM

#

so mesh then ?

frail sail Jul 25, 2018, 2:05 PM

#

one thing that is clear is that the WHOLE trail is present as soon as the shot happens

sullen forge Jul 25, 2018, 2:05 PM

#

or beam with some fancy material-ing

frail sail Jul 25, 2018, 2:05 PM

#

it's not a traveling thing

cold sorrel Jul 25, 2018, 2:05 PM

#

Beam over Ribbon!?!

solid stream Jul 25, 2018, 2:06 PM

#

oh true there is the beam too

cold sorrel Jul 25, 2018, 2:06 PM

#

What year is this!?

solid stream Jul 25, 2018, 2:06 PM

#

but beam is straight though

frail sail Jul 25, 2018, 2:06 PM

#

the whole trail appears, from start to projectile hit point, then there is some animation to make you "feel" like the projectile has traveled

solid stream Jul 25, 2018, 2:06 PM

#

https://cdn.vox-cdn.com/thumbor/r6bxuqo3IEHosrrzbZDUnL5lGDQ=/0x0:1920x1080/1200x800/filters:focal(364x254:670x560)/cdn.vox-cdn.com/uploads/chorus_image/image/59094129/fortnite_battle_royale_gunfire_1920.0.jpg

#

could also just be simple particles

frail sail Jul 25, 2018, 2:07 PM

#

that's not actually what you see in game haha

solid stream Jul 25, 2018, 2:07 PM

#

yeah

frail sail Jul 25, 2018, 2:07 PM

#

or maybe

solid stream Jul 25, 2018, 2:07 PM

#

I dont have the game at hand here so I cant check 😄

frail sail Jul 25, 2018, 2:07 PM

#

if you stop it it's like that

solid stream Jul 25, 2018, 2:07 PM

#

https://pbs.twimg.com/media/Dd-7LMeWkAAmJFF.jpg

#

how about this ?

#

the lines on the sides

#

could be very long particles

cold sorrel Jul 25, 2018, 2:08 PM

#

no

frail sail Jul 25, 2018, 2:08 PM

#

📎 unknown.png

#

they are the ones

cold sorrel Jul 25, 2018, 2:08 PM

#

Culling will murder you if you do

frail sail Jul 25, 2018, 2:08 PM

#

I was thinking of some cylinder mesh

#

no particle

#

just dynamic materials

#

but I'm not that into VFX

sullen forge Jul 25, 2018, 2:11 PM

#

robo recall uses mesh for its bullets

#

with some fancy material

#

very fancy

#

that way it does a good looking weapon trail without going through particle system

frail sail Jul 25, 2018, 2:11 PM

#

yeah, they really nail materials at epic. So complex.

cold sorrel Jul 25, 2018, 2:12 PM

#

Man, you get so many cool options when you don't have bulletdrop to worry about

frail sail Jul 25, 2018, 2:14 PM

#

yeah

#

hehe

#

I will try with cylinders then

#

tho I do have Luos's particle toolkit vol 1

#

might be worth checking it out

obtuse seal Jul 25, 2018, 3:26 PM

#

What is the absolutely gargantuan superforumula node for in Niagara graphs? 🤔

#

Also, out of curiosity I looked into writing a new node for Query a particle by its ID and getting the context for it back. A really naive implementation as a NiagaraNodeOP that gets the assigned tmpwriteindex and puts all of the default values into a parammap doesn't work out since the parammaphistory isn't built correctly (doesn't register the accordant input pins).

#

As well generally speaking it doesn't serve much purpose without a way to iterate on loops which would likely require a good deal of work in the hlsl translator

ocean hedge Jul 25, 2018, 4:07 PM

#

I think superformula is something @strong carbon cooked up

strong carbon Jul 25, 2018, 4:11 PM

#

Those scripts are an implementation of this. There should be a location module in there that lets you play with them. If not hook it into position and you can generate all these weird patterns. Just a fun toy.
http://paulbourke.net/geometry/supershape/

ocean hedge Jul 25, 2018, 4:27 PM

#

We'll probably have to implement the lookup particle variables by ID using a data interface, as that can do loops and interface with other C++ logic

obtuse seal Jul 25, 2018, 4:53 PM

#

@ocean hedge I had looked into implementing particle lookup at the DI level but avoided it as it seemed to be the wrong level of abstraction for the use-case. However considering the benefits of the interfacing it provides it does seem to be the most direct solution, so I'll turn my attention there. Also @strong carbon thanks for the link 🤓

obtuse seal Jul 25, 2018, 8:15 PM

#

Where is the code for the generic Set Variables module laid out in the Niagara source?

indigo jolt Jul 26, 2018, 2:10 AM

#

just spent 30 minutes trying to "logic out" how to make a Tetrahedron in 3ds Max

#

that's the pyramid with a triangular base

#

i succeeded but god was it annoying

steel sable Jul 26, 2018, 4:51 AM

#

~~noob niagra question but how do i add an emitter I've made to a new system? o.O~~

#

woops nevermind i found the docs https://docs.unrealengine.com/en-US/Engine/Niagara/HowTo/SpriteEffect

viral wadi Jul 26, 2018, 3:07 PM

#

@obtuse seal UNiagaraNodeAssignment::InitializeScript builds a local graph in code for that module

obtuse seal Jul 26, 2018, 4:09 PM

#

@viral wadi thanks for that 👍

viral wadi Jul 26, 2018, 4:18 PM

#

one of the things I want to explore in the future is having a way to make similar nodes easier where you somehow define the graph snippet to be used, and then you can add multiple calls to that same snippet directly from the stack in a single module

obtuse seal Jul 26, 2018, 4:19 PM

#

I was looking into something of the sort myself haha

ocean hedge Jul 26, 2018, 4:42 PM

#

Ie a way to do static for loops

steel sable Jul 26, 2018, 5:14 PM

#

in Niagra, If i want to render a "magic circle" on the ground do i need to use a mesh render or is there a way to have a sprite render have a non-camera facing orientation (e.g. world up)

obtuse seal Jul 26, 2018, 5:17 PM

#

@steel sable You should be able to use the Particles.SpriteFacing parameter to set the sprites z-up

steel sable Jul 26, 2018, 5:20 PM

#

@obtuse seal Thanks! That was the missing peice. I also had to set facing mode to custom and custom facing vector to 1,1,1 (for anyone else wondering)

ocean hedge Jul 26, 2018, 5:22 PM

#

yep, that's the way to do it

#

update... livestream will start in about 40 mins for Niagara https://www.twitch.tv/unrealengine

Twitch

UnrealEngine - Twitch

Unreal Engine - An Introduction To Niagara

▶ Play video

#

I'll be in too, so if you have programmer questions.. I'll hopefully have answers 😃

obtuse seal Jul 26, 2018, 5:23 PM

#

👀

steel sable Jul 26, 2018, 5:32 PM

#

sweet

#

in niagra, how would you implement a "flicker" for a particle?

obtuse seal Jul 26, 2018, 5:35 PM

#

Lots of different approaches, depends on the particulars of the particle 🤔

steel sable Jul 26, 2018, 5:39 PM

#

so I just have these simple magic circles randomly spawning (box location) and spinning around and slowly fading out ( opacity ). I'd like them to flicker a bit, somewhat randomly

#

📎 unknown.png

obtuse seal Jul 26, 2018, 5:40 PM

#

Is it a texture or material? If you do it with material then you can handle the appearance there, otherwise you want to make a pseudorandom contiguous value from 0-1 and and assign it to the particle opacity

cold sorrel Jul 26, 2018, 5:45 PM

#

Ash-nazg thrakatuluk

#

You simply utter the black speech inside the editor and it'll flicker

obtuse seal Jul 26, 2018, 6:06 PM

#

@steel sable Not sure precisely what appearance you want but a quick and dirty method is linking a bunch of sines with different periods https://gyazo.com/0dd10ba8eb7dba59475b7ffc2c9d1048

Gyazo

▶ Play video

#

Can try linking something like this into the particle color alpha 8*sin(6*sin(7*sin(Emitter.Age)))) * Particles.NormalizedAge

#

*through a custom expression that is

#

you could do this in a visual script as well

sullen forge Jul 26, 2018, 6:13 PM

#

niagara hallway 😍

obtuse seal Jul 26, 2018, 6:14 PM

#

Crossposting in discord and twitch 🤔

brittle remnant Jul 26, 2018, 6:41 PM

#

@indigo jolt Just a heads up for next time you need to make a tetrahedron. Just use a cone primitive with 3 sides. 😄

#

@obtuse seal Interesting question: Is it now more efficient to do flickering per particle in Niagara VS doing a flicker effect inside the material? I think pre-Niagara my answer would have been "do it in material because CPU cost of particles is high"

indigo jolt Jul 26, 2018, 6:46 PM

#

hmmm a cone! that does sound like it would work

obtuse seal Jul 26, 2018, 6:46 PM

#

Yeah I think you would be saving CPU time doing the flicker in a mat but doubtful it's a large cost in either case @brittle remnant

brittle remnant Jul 26, 2018, 6:47 PM

#

@obtuse seal Even considering Niagara? My understanding is that it all compiles down to HLSL that runs on the video card?

obtuse seal Jul 26, 2018, 6:48 PM

#

The compiled assembly from the cross compiled hlsl executes on a CPU vector VM or the GPU (dur) depending on which it targets @brittle remnant

brittle remnant Jul 26, 2018, 6:49 PM

#

@obtuse seal So essentially its up to the dev to decide where to do the work? Seems like I would always choose the GPU since theres so much more power there?

obtuse seal Jul 26, 2018, 6:50 PM

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It can be a performance improvement to do simple particles on the cpu and save gpu time if you're gpu bound. particularly dependent on the project in question @brittle remnant

brittle remnant Jul 26, 2018, 6:50 PM

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Awesome thanks! Looking forward to getting Niagara immersed soon!

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While I'm in here learnin' stuff. Is there still a significant CPU overhead for spawning particles for GPU side Niagara? (Similar to the old GPU particles) or has that bottleneck been removed with the new system?

obtuse seal Jul 26, 2018, 6:56 PM

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@brittle remnant I think like 3 people would even be able to say for certain but I think that the GPU calls to run the shaders are packed together now which saves draw calls

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Not sure specifically what cost you're talking about tho

brittle remnant Jul 26, 2018, 6:57 PM

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My understanding was that there was CPU overhead specifically connected to spawning gpu particles in cascade. Was wondering if that was now gone.

obtuse seal Jul 26, 2018, 6:57 PM

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This is a good question to ask on the stream so I'll send it there @brittle remnant

brittle remnant Jul 26, 2018, 6:58 PM

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😄

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I feel like I should be watching this stream!

obtuse seal Jul 26, 2018, 6:58 PM

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https://www.twitch.tv/unrealengine get in here

Twitch

UnrealEngine - Twitch

Unreal Engine - An Introduction To Niagara

▶ Play video

sullen forge Jul 26, 2018, 6:58 PM

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its a great stream

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very interesting stuff shown as an overview of the thing

long rapids Jul 26, 2018, 7:09 PM

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hey gang, i want to get a mesh particle to orient along the vector it's being emitted on, and rotate appropriately after spawned

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📎 missle_rotate.jpg

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the trail shows its' vector....(just ribbon emitter attached), and you can clearly see the missle is staying horizontal, not 'pointing' to where it's headed

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any suggestions/clues?

obtuse seal Jul 26, 2018, 7:13 PM

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@long rapids Gonna be honest I can't make out a missile in that but for a Cascade system you can have your mesh orient to velocity by setting Screen Alignment in the Required module to PSA Velocity

long rapids Jul 26, 2018, 7:14 PM

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@obtuse seal (its the white thing dead-center)....yeah i tried all the Alighnment features, but they dont seem to work with Mesh particle

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Alignment variants, i should say

obtuse seal Jul 26, 2018, 7:15 PM

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Your missile mesh will need to face positive x while at rest for it to face properly towards the velocity vector I think

long rapids Jul 26, 2018, 7:17 PM

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hmm.....if it's original orientation was off, woudn't you expect to see it update over life.....just "wrong" ?

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as is, it just stays at default orientation

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📎 missle.jpg

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maybe this is a bit more clear

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i shoot it "up" and sideways then have gravity bring it down.....and it just lays flat even with PSA Velocity set

obtuse seal Jul 26, 2018, 7:19 PM

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@long rapids Try making an empty Cascade emitter with Mesh typedata and set it to velocity alignment. From there compare your implementation 🤔

long rapids Jul 26, 2018, 7:19 PM

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hmmmm....lol. ok.

obtuse seal Jul 26, 2018, 7:31 PM

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Didn't show skeletal mesh sampling on stream 😡

steel sable Jul 26, 2018, 7:51 PM

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@obtuse seal so in the twitch live stream in their expressions content sample I noticed they have a built in hlsl 'rand' function I was able to add flicker to my particle by simply adding this color variable modify at the bottom of my stack! so easy and straighforward, niagra is really awesome!

📎 unknown.png

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https://www.youtube.com/watch?v=Vgj2heyUJYY

YouTube

tmektmek

UE4 Niagra Magic Circles

▶ Play video

obtuse seal Jul 26, 2018, 8:04 PM

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looks good 👍

ocean hedge Jul 26, 2018, 8:28 PM

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@obtuse seal Sorry, we totally ran out of time

steel sable Jul 26, 2018, 8:28 PM

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did anyone catch how you're supposed to define and set a new "temp" variable. I can't seem to do it.

obtuse seal Jul 26, 2018, 8:28 PM

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Don't worry, I jest 😜

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@steel sable you can create namespaces at will so make a new variable of the desired type and rename it however

ocean hedge Jul 26, 2018, 8:29 PM

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@steel sable in the Parameters panel, click on other, add the variable and type in Temp.NewVariable as the name (for instance)

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I hope that folks found today's livestream useful.. we're actively looking into multiple ways to get the information stuck in our heads out into the world..

sullen forge Jul 26, 2018, 8:30 PM

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@steel sable One ring to rule them all, one ring to find them, One ring to bring them all and in the darkness bind them.

steel sable Jul 26, 2018, 8:31 PM

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@ocean hedge the stream and the content sample are so helpful thank you!

obtuse seal Jul 26, 2018, 8:31 PM

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VFX runs on dark sorcery apparently kappa

sullen forge Jul 26, 2018, 8:31 PM

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@ocean hedge great stream

obtuse seal Jul 26, 2018, 8:31 PM

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Anxiously awaiting the really cool content examples to come 👀

ocean hedge Jul 26, 2018, 8:31 PM

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wait til you see the fun jon and wyeth are having with the texture data interface

sullen forge Jul 26, 2018, 8:32 PM

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i can imagine

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funky shaders trhough render textures

obtuse seal Jul 26, 2018, 8:32 PM

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Curious about that fur sim mostly but what's possible with textures and render targets is already getting too insane for me to even comprehend applications

steel sable Jul 26, 2018, 8:32 PM

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@ocean hedge for sprite particles angular velocity doesn't work correct? (it's only for mesh paritlces?) is there any thing similar for giving a sprite particle a constant 'spin' or should i just modify SpriteRotation each update.

ocean hedge Jul 26, 2018, 8:33 PM

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that's right.. angular velocity doesn't currently work

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I suppose you could do something with the custom facing, alingment, and rotation vectors to achieve the same thing

obtuse seal Jul 26, 2018, 8:33 PM

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Just something like this @steel sable https://gyazo.com/19d5527d9ce6ea0ceee3a2bf26846477

Gyazo

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The B factor is the speed multiplier so you can play with that

sullen forge Jul 26, 2018, 8:34 PM

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@ocean hedge im curious about one thing. If you can keep binding properties near endlessly, isnt it pretty much a node tree?

ocean hedge Jul 26, 2018, 8:35 PM

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yep

sullen forge Jul 26, 2018, 8:35 PM

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in that case, why not a node tree itself ? Reminds me of Cycles "non nodes" mode

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wich basically collapses a node tree into a stack

steel sable Jul 26, 2018, 8:35 PM

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yeah i wound up doing basically the same thing but with inline expression. was just curious if there was a built in method since rotating a sprite would be a core thing.

📎 unknown.png

obtuse seal Jul 26, 2018, 8:35 PM

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It's one of those modules that got missed on

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expect to see it in dev-niagara soon

ocean hedge Jul 26, 2018, 8:39 PM

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@sullen forge It's definitely a philosophical question. The reality is that most game effects work is really a lot of really common, shared base logic with customized tweaks specific to the situation. We thought that blueprints tend to spiral out of control quickly into spaghetti messes that aren't easily readable. The stack allows you the flexibility to string together a lot of really common pieces of functionality very quickly without a lot of glue wiring. It is also easy to at-a-glance scan the stack and understand what is going on. With the ability to create expressions, dynamic inputs, and modules, you can do everything you want in the graphs. It feels like the best of both worlds for us and the majority of our audience.

steel sable Jul 26, 2018, 8:40 PM

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Hmmm. So i try to add a new Particles.Spin float but it doesn't appear in the available choices for add new variable for the set variable module.

📎 unknown.png

obtuse seal Jul 26, 2018, 8:41 PM

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didn't we stomp that bug with new vars not being intiialized

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"we" kappa

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You need to give it a default value so that it's initialized in the script

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@steel sable You can click and drag it into the Set Variables module and that should work

steel sable Jul 26, 2018, 8:42 PM

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that worked thank you 😃

obtuse seal Jul 26, 2018, 8:43 PM

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Odd, I was pretty sure there was a change at some level to initialize new vars so that they were accessible but it doesn't seem to work that way anymore

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really odd

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am I insane

sullen forge Jul 26, 2018, 8:43 PM

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@ocean hedge thanks for the answer, it makes sense

ocean hedge Jul 26, 2018, 8:45 PM

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something may have been lost when coming back from 4.20

obtuse seal Jul 26, 2018, 8:45 PM

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It appears to be the case

wild rock Jul 26, 2018, 8:45 PM

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Has anyone used the Spline Component? I'm trying to work out how my mesh should be set up, relative to origin etc. Currently it's not being stretched correctly, it never actually touches the final point in the spline.

sullen forge Jul 26, 2018, 8:47 PM

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once i update my RPG project to 4.20, im going to try to set goblins on fire through niagara

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and other objects on fire

obtuse seal Jul 26, 2018, 8:47 PM

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other objects i.e. everything

barren raven Jul 26, 2018, 9:06 PM

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Great stream guys and thanks for the amazing content examples. Super exciting stuff!

steel sable Jul 26, 2018, 10:00 PM

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@ocean hedge I'm not sure if this is a bug or i'm not doing it correctly. But I have never been able to create a Temp variable and set it. I even tried to modify Content Example "1.5 Blend Attributes by Value" emmiter by removing "Temp.DistanceFromCenter" and then trying to add it back but it won't seem to let me. Here's a video showing what I mean. https://youtu.be/2o04LeW3g-c
(Edit: the only way i was able to do it was to add another float variable like 'Particles.Age' and then double click the name to rename it to 'Temp.DistanceFromCenter')

YouTube

tmektmek

Can't seem to set temp variables (even in content example emitter ...

▶ Play video

long rapids Jul 26, 2018, 10:43 PM

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i want to fire an emitter, single emitter and have it auto destroy itself when done emitting (loop=OFF of course)

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is there a way to do this?

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auto deactivate will kill the emitter?

steel sable Jul 26, 2018, 10:53 PM

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@long rapids If you are asking how in Niagra, you should be able to set Num Loops=1 on the emitter (Also called Max Loop Count in Emitter life cycle)

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hmm however i don't think the actor will destroy itself, just deactivate.

short sorrel Jul 26, 2018, 11:08 PM

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all, any pointers on how to have a widget which has an lcd feel? thinking about an old style gps

brittle remnant Jul 26, 2018, 11:36 PM

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Epic folks, Is there any plan to improve the default motion blur implementation with regards to sprites / particles? It's easy to see in the Niagara test examples how the circular sprites get distorted strangely by motion blur when moving.

viral wadi Jul 27, 2018, 12:36 AM

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@brittle remnant It's a difficult problem with transparent geometry and the velocity buffer which I don't think there will be a solution for any time soon. In the short term the best way to handle it for transparent sprites is to scale them using velocity, or other similar tricks, or if possible make them masked sprites so that they can write to the velocity buffer and will blur correctly.

steel sable Jul 27, 2018, 1:21 AM

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Not sure what I was going for but this is what I wound up with 😄 https://youtu.be/pEpGxUmMhEQ

YouTube

tmektmek

More Tinkering with UE4 Niagra

▶ Play video

dark rain Jul 27, 2018, 1:56 AM

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I'm trying to make a bullet tracer. I want it to look like smoke, so I used a beam emitter, mixed with some noise. The problem is, the noise looks makes it look like lightning. Is there a way to get the noise module to look like wispy smoke instead?

steel sable Jul 27, 2018, 3:13 AM

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@dark rain have you looked at this content sample? (From the Example Content project on the learn tab)
It seems like it would be a good start for wispy type beams.

📎 unknown.png

dark rain Jul 27, 2018, 3:15 AM

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that looks good, I'll check it out!
Thanks @steel sable!

steel sable Jul 27, 2018, 3:15 AM

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@dark rain It uses Curl Noise with these settings

📎 unknown.png

dark rain Jul 27, 2018, 3:18 AM

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oh that's Niagara..
I'm still working in Cascade 😛

steel sable Jul 27, 2018, 3:19 AM

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lol i was just about to type that.

dark rain Jul 27, 2018, 3:19 AM

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I tried upgrading my project, but a bunch of plugins failed to compile

steel sable Jul 27, 2018, 3:19 AM

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is there a curl noise module in cascade? maybe those settings would be similar

round fog Jul 27, 2018, 7:44 AM

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There is not. The common way to get that kind of noise effect in Cascade is with gpu sprites and vector fields, but then you can't have ribbons.

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Did I mention how happy I am about Niagara? :)

plain dock Jul 27, 2018, 7:59 AM

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Has anyone else encountered the issue of not being able to open the Niagara level in the content examples?

devout portal Jul 27, 2018, 1:04 PM

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@plain dock check if Niagara plugins are enabled

mortal lily Jul 27, 2018, 1:04 PM

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Quick one: Was the "Surface Only" checkbox replaced to only use the Surface Only Band Thickness one? I can't find it anymore under my sphere location.

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📎 sphere.png

strong carbon Jul 27, 2018, 1:08 PM

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Yep, it's now an inline checkbox on the parameter. We will update the docs

mortal lily Jul 27, 2018, 1:09 PM

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Aye. Thank you!

devout portal Jul 27, 2018, 1:13 PM

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@strong carbon will is be possible to edit docs later? afaik Epic now uses some profile subsystem for Docs (probably question for Docs team)

strong carbon Jul 27, 2018, 1:13 PM

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Sorry, no idea

devout portal Jul 27, 2018, 1:22 PM

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Hm. I think I found a bug...

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need to test to confirm

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Autosave crashes when trying to save modified Niagara files.

obtuse seal Jul 27, 2018, 1:41 PM

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There was an old bug I had once with creating a new empty niagara script and crashing on autosave without having edited any parameters but I couldn't replicate it

devout portal Jul 27, 2018, 1:41 PM

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nope...it was not a bug...(well UE4 crashed, but only thanks to 0 bytes left on disk)

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hmm...but ue4 and project are stored on different disk...hmmm

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@strong carbon fix suggestion for niagara content example 2.2, it now has hardcoded target, also scale depends on position (i.e. if you code the position as relative it still will be affected by the emitter position (curve arc), also this effect is referenced in Level Blueprint (kind of complex as Niagara example)

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sorry if i got this example wrong (it's about realtime endpoint update)

strong carbon Jul 27, 2018, 1:56 PM

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The hard coded target is intentional, as it represents the type of world space location result you can get from a line trace in blueprint, say a bullet trace from a gun. You can override that with whatever you like. The reference to level blueprint doesn’t have any effect on the simulation so I wouldn’t consider that complex as it is not feeding any parameters to the sim (it’s just moving it around in space and rotating it. So I don’t consider those bugs, but they definitely could use better documentation on why the settings are they way they are.

obtuse seal Jul 27, 2018, 2:00 PM

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How do you expose the Outputs expander in a Set Variables module anyway? 🤔

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oh wait it's exposed for every module

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oh there's an option under the 👁 symbol

devout portal Jul 27, 2018, 2:04 PM

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So, how to set the endpoint of the beam through blueprint then? In this example only the actor position is changed.

obtuse seal Jul 27, 2018, 2:04 PM

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expose it as a User param and then set it through BP

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specifically using a SetNiagaraVariable node

devout portal Jul 27, 2018, 2:19 PM

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@obtuse seal i'm having the issue with the first thing...

round fog Jul 27, 2018, 4:37 PM

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@devout portal create a new parameter in the parameter list, in the User namespace

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You should be able to set that through BP

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And then use that parameter in the stack for your position

devout portal Jul 27, 2018, 5:16 PM

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@round fog , @obtuse seal thank You!

round fog Jul 27, 2018, 5:17 PM

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Got it working?

devout portal Jul 27, 2018, 5:17 PM

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@round fog yep

round fog Jul 27, 2018, 5:18 PM

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I haven't messed with that yet, so glad to hear it :)

devout portal Jul 27, 2018, 5:25 PM

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📎 param_niagara.gif

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📎 screenshot.1532712310.png

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📎 screenshot.1532712305.png

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📎 screenshot.1532712293.png

steel sable Jul 27, 2018, 7:37 PM

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So when using a User property like above. Is there a way you can set those user properties to default values from within the effect/system editor windows? Otherwise they'll initialize to (0,0,0) which could make it hard to visualize your beam within the effect/system editors.

ocean hedge Jul 27, 2018, 8:38 PM

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📎 unknown.png

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The values you set in the System Exposed Parameters window are the defaults it gets created with in-world

indigo jolt Jul 27, 2018, 8:48 PM

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hey anyone got a good idea on what's the best way to do a procedural ring in material that has soft edges on both sides and can get be adjusted easily to vary thickness?

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must be SOFT edges

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so far doing this and it's not really doing it for me https://i.gyazo.com/bfb914d06023a68dd3076cbba6bc111d.png

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i did this method too, but it's way too crisp https://i.gyazo.com/05c180715731e3946e61c44a4ea0f050.png

sullen forge Jul 27, 2018, 9:03 PM

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distance field-ish stuff

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essentially, make it 1d. Work on the distance to center

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calculate the distance to a point, wich is your radius

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there is even a distance node

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so do distance ( radius, targetradius) basically

indigo jolt Jul 27, 2018, 9:09 PM

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hmmm i'll tinker around with distance node a bit, i don't really understand the math well enough to do what you said verbatim t hough

sullen forge Jul 27, 2018, 9:10 PM

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http://iquilezles.org/www/articles/distfunctions/distfunctions.htm

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this ones are 3d

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but will prove useful

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📎 unknown.png

indigo jolt Jul 27, 2018, 9:56 PM

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hmmm thanks, but i don't know math, i just know nodes

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i have very dumb methodology 😦

brisk wedge Jul 27, 2018, 10:16 PM

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@indigo jolt where is the difference between node math and number math?

📎 math.png

indigo jolt Jul 27, 2018, 10:36 PM

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comprehension

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i only understand the actual mathematical concepts behind about 25% of these things so I'm usually repeating things that i've seen work before, or I'm adding/removing various nodes and watching visually what happens

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and yeah what you've got there does a good ring, but it has crisp edges. i'm hoping for a soft edge solution

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sort of like a radial gradient

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i've got a real nice crisp edge solution right now and it actually looks fairly legit in-game so i may just give up and stick with it, but a soft edge ring would be pretty useful in general, especially on large scale effects where i want a shock-wave type thing with infinite pixel resolution

brisk wedge Jul 27, 2018, 10:40 PM

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well distance gives you a gradient from the center

indigo jolt Jul 27, 2018, 10:40 PM

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ya i do get the feeling distance node will play a role in a soft edge ring solution, i just don't know what solution will look like yet

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hoping i can shortcut the 8 hours of tinkering 😃

brisk wedge Jul 27, 2018, 10:43 PM

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you need to fade the color when the distance is close to the inner/outer radius

indigo jolt Jul 27, 2018, 10:44 PM

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oh the above example will do soft edges if i change parameters?

drifting wave Jul 27, 2018, 10:46 PM

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have you tried using Radial Gradient Exponential?

brisk wedge Jul 27, 2018, 10:46 PM

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not really its only the distance gradient where distance is between Inner Radius and InnerRadius+Thickness

indigo jolt Jul 27, 2018, 10:46 PM

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yeah radial gradient exponential is the first thing i tried, but that's good for a circle, not so much a ring

drifting wave Jul 27, 2018, 10:47 PM

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Im looking at a ring made with 2 radial gradient exponentials, I would show you a pic but NDA

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Something like this could do it too. Value adjustments can sharpen or soften it

📎 ring.PNG

strong carbon Jul 27, 2018, 10:54 PM

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You can just use spheremask if you like, very controllable.

📎 unknown.png

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The abs is there in case you put a subtract in front of the length calc to give you another "point" in the center

indigo jolt Jul 27, 2018, 11:12 PM

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hmmmm i think the Spheremask thing looks good

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Joesith i will try your method too, it looks like it might have trouble "thinning out" to a fine point smoothly, not sure

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i did something similar and it had problems on that front

cold sorrel Jul 28, 2018, 10:44 AM

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Has anyone else run into issues with the PseudoVolumeTexture function from Ryan Brucks volume examples? It offsets the texture when using 16x16 textures and I can't figure out where that function lives so I can fix it.

analog onyx Jul 28, 2018, 1:09 PM

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@cold sorrel PseudoVolumeTexture is defined in Common.USH. I never used it, consequently, never had issues.

cold sorrel Jul 28, 2018, 1:24 PM

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Hmm... Strange.

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That's the only part of the code that takes in the framesXY as an argument so I guess that's what causes it.

devout portal Jul 28, 2018, 2:33 PM

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Where is the Static mesh defined for niagara 3.1 example? the one that referenced in the level (not the one in the system)

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oh, i see now, the source in the override

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i think this is one of the most powerful features

devout portal Jul 28, 2018, 4:13 PM

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@strong carbon sorry for poking, but how is SampleStaticMesh working? I see random Tri Coord node, how it randomizes the coordinates for specified mesh?

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Is it possible to get vertices?

obtuse seal Jul 28, 2018, 4:45 PM

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@devout portal You can see how the operation works in NiagaraDataInterfaceStaticMesh, the Random Tri Coord node gets a Random Tri Index which itself calls Random Section that uses an FStaticMeshAreaWeightedSectionSampler to choose an arbitrary section. Regarding getting vertices there is a Get Vertex Position node that takes a tri index argument I believe

cold sorrel Jul 28, 2018, 9:37 PM

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https://imgur.com/a/0XgUNJg

Imgur

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Mmmmm, I like it deep!

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My Bullethole generator is coming along 😃

indigo jolt Jul 28, 2018, 9:43 PM

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whoa that looks fantastic

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dbuffer decal with POM?

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and how many layers?

cold sorrel Jul 28, 2018, 9:45 PM

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Max 32

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8 when head on