⚛️┃physics

[neon solstice]

But then it has been decided to set target FPS to 60

and my character started moving way slower

of course, I may increase forwardSpeed and other speeding constants, this will fix issue, I think. But.... I am curious - why movement was faster when FPS was rocketing to 400

[viral ginkgo]

@open escarp You gotta move those grabber arms with force

[open escarp]

Rigidbody2D.AddTorque?

[viral ginkgo]

@open escarp That would work if you want to use that

or maybe some joint motors

I'd prefer torque

Hmm, maybe joint motors would better though

[open escarp]

Thanks, I will try both

[viral ginkgo]

If you do torque, one arm might close fast while the other arm is pushing against the balls

It would be better to control the arm angles in a stable way

[open escarp]

Thanks

[viral ginkgo]

np

[supple sparrow]

you can gather input in Update but you should mess with rigidbodies only in FixedUpdate

[neon solstice]

do I rename Update to FixedUpdate?

[timid dove]

All of this Update code should be in FixedUpdate

[dreamy pollen]

Given two rotations, a and b, how do I determine the torque needed to move the Rigidbody from a to b, ignoring its mass (Forcemode.VelocityChange)

[timid dove]

Torque gives you a velocity

not a difference in rotation

similar to how force gives you a change in velocity, not a distance

technically any amount of torque will get you to b (as long as it's in the right direction)

the question is how long will it take?

And at what angular velocity will you still be spinning when you get there?

[dreamy pollen]

I wish to move a dynamic rigidbody from rotation a to b over one frame, using AddTorque and subtracting its angularVelocity

[timid dove]

if you want to just do it over one frame, don't bother with torque. Use MoveRotation

[dreamy pollen]

I need the body to report that it has an angular velocity, it's a spinning platform the character controller will ride whose properties are being analyzed

[timid dove]

I think this would do it?

Quaternion start;
Quaternion end;

Quaternion diff = end * Quaternion.Inverse(start);

// required velocity to do that diff in one physics frame:
Vector3 angularVel = diff / Time.fixedDeltaTime;
rb.angularVelocity = angularVel;```

We can also make that done with torque but it'd require a few more calculations with the current angularVelocity and the moment of inertia of the body

[dreamy pollen]

Another requirement I guess I should have mentioned is that I have to use the freeze rotation rigidbody constraints as I want to only move this dynamic body myself, with no consideration to any other rigidbodies

@timid dove

So I must use AddTorque

I usually just do something like this:
rb.AddTorque(torque - rb.angularVelocity, ForceMode.VelocityChange);

It appears I cannot set angularVelocity on a rigidbody with frozen rotation constraints, while AddTorque still works

(I recognize this is rather niche)

maybe I can get a signed angle delta on all 3 axes

[timid dove]

The only effect of AddTorque is to modify the angularVelocity

it won't let you get around rotation constraints being enabled

[dreamy pollen]

That is not true

unless Unity is bugged, AddTorque does let you circumvent constraints

[timid dove]

sounds like a bug to me

also doesn't make any sense 🤔

[dreamy pollen]

Possibly only ForceMode.VelocityChange has this effect

[timid dove]

that would be even more surprising than the previous revelation

[dreamy pollen]

give it a try 😐

(also, can we keep this on the down low? I don't want Unity to "fix" this... lol)

[timid dove]

later I will

[dreamy pollen]

@timid dove the following appears to have gotten me what I wanted:

Quaternion fromRotation = //...
Quaternion toRotation = //...

Quaternion deltaRotation = Quaternion.Inverse(fromRotation) * toRotation;
Vector3 deltaAngles = deltaRotation.eulerAngles;
if (deltaAngles.x > 180f) deltaAngles.x -= 360f;
if (deltaAngles.y > 180f) deltaAngles.y -= 360f;
if (deltaAngles.z > 180f) deltaAngles.z -= 360f;

rb.AddTorque(deltaAngles - rb.angularVelocity, ForceMode.VelocityChange);

[nocturne lagoon]

Hey everyone! ive been trying to make an online movement shooter but i keep running into this issue, i tried everything i could but could not figure out the issue 😦

Would really appreciate if anyone could help

using a Character Controller

Not using any particles

[timid dove]

You'd have to share your code but you're doing one or more calculations that are resulting in NaN and trying to use that somewhere that is upsetting things

[nocturne lagoon]

I found a workaround, basically limited everything that could lead to infinity or NaN