Different UV island having bleeding between them.

[Oscar2364281464p6]

I found something which I think shouldn't happen.
I try to create a color for the character underwear different from their skin (the style of the textures is flat colors), so I split those UV islands from the rest of the body, but for my surprise I found that despite of that still happen bleeding between them, I tried using masks, with polygon fill, and painting with brushes with the Alignment properties set in UV and immediately after paint, or click the bleeding returns.
As you can see in the images even when I export the texture with dilation it seems bringing the colors from the other UV island.
 
Is there a property or setting that I need to switch to avoid this?   

*I don't want to create different meshes for each color division, to avoid additional edges and vertex with their respective normal, mesh-smoothing misalignment and also avoid the hurdling with the skin weights.

Thank you

[Cedric Marchessoux]

You have too many islands in one UV Space [0;1] especially for a full body.
Therefore your texel density is very low (and bad in fact) resulting in this low resolution artefacts when applying textures.

Solution 1: split it in different textures sets and then try to increase the space of the islands in the UV space [0;1]. To create textures set in the modeling software apply the same material to the parts you want for one texture set.

Solution 2: Keep one texture set but split in UDIMs using the UV Tile workflow. This would allow you to have multiple tiles and have them in the same texture set in case, you want to paint across UDIMs and use the same shader.

In the doc of Painter you will find info about it.<

hope it helps

[LaurieAnnis · Accepted solution]

I believe the answer you were given is wrong.  Even if you have better texel density and wide space between UV islands and a very high resolution image, you will still get bleed between separate UV islands if the UV Padding setting under Texture Set Settings at the bottom of the Channels section is set to 3D Space Neighbor.  Setting this to UV Space Neighbor seems to fix this, even after switching back.  This seems to be a bug.

[Cedric Marchessoux · Accepted solution]

Got some feedback from the team:
The UVs look fine in the screenshot and it is indeed just a setting to change. 
Neverthless the UV scaling could be a bit better to reduce the padding improve texel density, but nothing critical in this case. So there is no bug.