Slicer color painting -- not just on the layer I mark?

[solid gyro]

Hi, I'm having some difficulty understanding how painting actually works. I've tried painting a model both via "fill" on a flat surface as well as via layer height, but for some reason, it seems to be starting the color a few layers early and building up.

Why is this?

I care because (a) superfluous filament changes and (b) my model is almost always failing at this point (well, tried twice, with two failures), and it seems like there's some issue with the two adhering at this point. This is causing rough surfaces and blobs, which seems to be snagging the print head, pulling it off the bed at around layer 185-187 (out of 190). I probably should fix that, but I'm not sure why; both the black and white filaments are PLA (Overture), both dry, both print beautifully on their own, and the bottom layers (where I did the same split) is perfect, so I'm hoping that a top layer only would bond nicer.

The model is https://makerworld.com/en/models/474865?from=search#profileId-385470, for what it's worth. I'm using the default 3mf, with just changes for painting. A photo and screen shots are below in the thread

screenshots of the slicer for the top 6 layers. I'd (tried to) paint just the top layer

[short dome]

I didn't realize it had this behavior but I just confirmed by testing myself that fill tool does indeed do multiple layers. I had thought when I tested it in the past it did not behave that way, I am not sure if I am mistaken there or if it is a more recent change.

As for the adhesion, I find I usually get terrible adhesion between color changes because they are so slow the previous layer cools down too much. It is lessened if I print in an enclosure, turn the fan speed down, and raise the temperature a little.

I did find this issue related to painting color depth and it changing. https://github.com/SoftFever/OrcaSlicer/issues/6617

[solid gyro]

interesting! I have an enclosure, but I didn't think about the effects of bonding hot to cold. That would explain a lot. It's a Bambu printer, and the color changes take a while (I've never used anything with multiple extruders, but I assume it's much better there)

[solid gyro]

Thanks for the confirmation that it's not my operator error! 🙂

[short dome]

Hot to cold makes a huge difference. I actually leverage it on purpose for supports, I set the support top layer to run super slow, with lots of fan, over-cooling it which makes the material printed on top not stick well so the supports break off easily.

[solid gyro]

ooh, sensible!

I'm coming from an ender, where everything was slow; this probably explains why more supports are sticking much more!

[lunar bramble]

Has there been any work on this issue? I see that the linked github issue was closed. But, the issue still happens.

[umbral solar]

no it hasn't been even noticed by any dev yet...

it's an open source software so you're supposed to write your own code i guess, though I do feel that a feature vote system should be there

[short dome]

Occasinally I see bounties pop up, where someone wants a feature so badly they literally put their money where their mouth is and offer x dollars for a feature to be implemented by somebody, but the vast majority of people just want people to do work for them for free so it's pretty rare. It is based on Bambu Studio which is based on Prusa Slicer and they share features back and forth fairly often, so if you have paid one of those companies money for a printer you could try requesting the feature there.