[Solved] Can't paint certain pixels at edge of UV for low-res texture file

[nickburnsap]

I'm currently working on a throwback game that uses low res textures for its art style, but some models when I paint near the edge of a UV just refuse to draw on that pixel.

Sometimes I can get away with drawing in the 2D view at the top, but not always, and even still I consider that not a valid solution since if I am painting a gradient on the mesh, the unpaintable spot still remains the color below.

This has happened with almost every mesh I have exported, but as an example see this tree model. The grey on the branch there is the base color of Layer 0, and the brown is what I have painted in the 3D view (and tried in the 2D view). Notice the end of it just won't paint!

https://imgur.com/a/OK4Np7a

Is there a way to force it to paint every pixel of a texture no matter how small?

A few notes:

• I have tried playing with the padding preferences, and all 3 options don't solve the problem. Though Naive padding seems to get closer.
• I'm working with a 128px texture
• The model is an FBX, exported from blender with Smart UV Project - and I don't want to sit there in blender and line up UVs
• Using the latest 2023.19 version of 3DCoat Textura
• This issue persists even when using the Flood Fill tool, Eraser or any other painting tool.

Any help would be appreciated!

 

[nickburnsap]

Okay final update, I seem to have found the work around. Might be a bug, not sure.

For my textures, 128x128, I can Smart UV Project in Blender as desired, with 0.20 island padding. Make sure you've Applied All Transforms on the mesh before export.

Within 3DC the issue is 99% solved now, all padding is acting as intended. But for the 1% that does, and this is the work around, just use the magic wand tool on the surface and it just, fixes itself. You have to do it all the time, so if you paint a thin area red and magic wand it and it fixes itself to red. If you then paint blue, it will stay red, but you can magic wand it and it will fix itself to blue. So make sure before export you magic wand any trouble areas.

Again, not sure if that means its a bug? But the magic wand tool just kinda kicks all the pixel in the selected area and wakes them up, and they take the correct color.

Cheers, thanks for the help though! Hopefully this helps someone else if they find it.

[Carlosan]

Hello

Never ever use Layer0 for any paint but transparency. If you hide layer 0 before export, you'll get transparency, assuming you've left some "holes" in the other paint layers.

It contains mesh data and a "base coat" of paint for baking.

The reason why 3dcoat keep "layer 0" as visible, it make user easy to color (overwrite layer 0) mesh.. (layer 0 keep alpha as 1.0 (no transparent) and color perfect 0.5 0.5 0.5 RGB) .
if there is not layer 0, you may not see any suface until you import map, or actually paint on surface in another layer. it make us difficult to paint.

watching your pic i think that the UVlayout need to be optimized before import it for painting process

look are the space in between UVislands, working at 128px it is huge.
try to increase uv coverage using pack islands in blender (It’s important to have enough space (Margin) between UV Islands)

Increasing UV Coverage value leads to the increasing Texel Density value, this in turn leads to the more efficient UV space usage and you can see more pixels on your model using the same texture.

[nickburnsap]

Quote

Never ever use Layer0 for any paint but transparency.

I was just using it here for showing, I normally don't paint on layer 0.

Quote

 increase uv coverage using pack islands in blender (It’s important to have enough space (Margin) between UV Islands)

When I bring it out of Blender, I usually use Smart UV Project, which automatically packs the UVs (https://imgur.com/xIDx1Lx)

And its important to try and keep all the islands relatively scaled so that the pixels (which at 128px are very obvious) are roughly the same size. Not to mention I'm trying to create a pipeline that is very fast to iterate on, and ideally I'd like to not have to sit there and mess with UVs for basic background props.

But the issue even persists where there are UV seams as well, like in this example: https://imgur.com/a/BcHfDNe

At the end of the day, if I'm doing a low-fi style there will be diagonal UV edges along pixels. Is there no way to force 3DC to just paint over the edge, and leave it to me to make sure it doesn't bleed onto other faces?

Thanks for getting back to me!

[nickburnsap]

I discovered what I was doing wrong - I forgot to transform all on the edited mesh before exporting the FBX from Blender, thus the UVs were scaled weird and incorrect.

That being said, it doesn't solve everything, even with the correct scaling, I still get the occasional pixel it will refuse to paint (https://imgur.com/a/TKqHIYd)

And in those cases, even hiding all the layers it still shows as a light grey.

So the question still remains which is, can I force it to paint over the edge of a UV no matter the scale of the pixel?

[Carlosan]

It is not possible, it is not a bug but how 3DC works

Try to move that verts slightly to put it into the square pixel painted previously

Export the texture to photoshop can help too