Hello!

I am using the Merge Textures option in CC3 as I want to use the model as a game character.
However, the face is too small in the texture atlas:



How do I customize the texture atlas in order to give 1/3 of the space to the head texture for example?
Or which other options do I have if this is not available?

Thank you!

I do not normally use Game Bases, but this is not even funny.
Nails, teeth, tongues and eyes are using more than a 1/4 of the space on UV map?
It should definitely be reported to Feedback Tracker.

This part of the pipe is provided by the 3rd party instalod https://instalod.zendesk.com/hc/en-us/articles/360015151574-Reducing-draw-calls-by-Material-Merging

You can see the settings CC calls it with in C:\Program Files\Reallusion\Character Creator 3\Program\Assets\Creator\LOD\MaterialMerge.json

"UVImportance":"Normal",
"GeometricImportance":"Normal",
"TextureImportance":"Normal",
"VisualImportance":"Normal"

• UV Importance measures the occupied UV space of the faces/meshes and will increase the weights accordingly, a single face occupying the whole UV space will be relatively bigger compared to a face that is very small in the UV space.
• Geometric Importance measures the world space area of the geometry and will increase the weights accordingly, bigger meshes will occupy more UV space in the resulting atlas.
• Texture Importance measures the texture sizes of the input meshes and will increase the weights accordingly, meshes with higher resolution textures will occupy more UV space.
• Visual Importance measures the visibility of meshes in the scene and will increase the weights accordingly, hidden faces and meshes will occupy less UV space.

In theory instalod is trying to balance all these things. I've seen it do well in sometimes... but often not. I went so far as to make a new set of nail textures that were just flat colour in all the channels, that didn't end up making them any smaller in the atlas :-(

I haven't tried playing with the settings in the MaterialMerge.json, let me know if you have any success playing with them. I'd guess UV ot Texture Importance is a factor in keeping the nails large in the atlas, I'd be tempted to drop that. Not sure why the face ends up so small.

I played with the settings, they seem to have very little effect on the atlas, it comes out the same.

I enabled the shell rotation, just to check the file was even being used, and that did rotate some of the islands. So the the file is used...

"ShellRotation":"None", 

"ShellRotation":true,

Not the best solution, but it did make a difference.

@Rampa  5 stars. Great solution. After you export the maps, you re-export the head?  how is your workflow, exactly?  Thank you !

That's why I said "not the best solution". I don't have a workflow to get a properly scaled export. Because changing it would generate a different UV. So it is not a complete workflow, and may not be a useful solution at all. If you only scale to 300 percent, instead of 999, it won't distort like that. Maybe you could shrink the head again in Blender?

Best results for baking with "All" is to leave all the textures at the default 2048, except for the head diffuse being scaled up. This is because the largest it will get is approximately a quarter of the map. So if you bake a 4K map, it will then be around 2K for the head, and everything else fits nicely, and should be enough resolution in most cases. You may want to still drop the nails and tongue resolution too, but it may not actually gain anything. Setting the rotation to "True" may help with packing efficiency in some cases, but I think it usually will not make any UV island scaling differences.

Ingenious idea, simple as well, love it!