Unfortunately there are more problems with UDIM in Maxwell 3.x
(tested on Windows 7 x64, Maxwell Render 3.2.1.5, Maya plugin 3.2.1.4)
1. Global bump and bump map channels doesn't work correctly (Maxwell Render engine problem):
In short. If your bump map textures have higher resolution than 200x200 they will be always blurred.
I talked with
Brany, (thanks anyway for his help):
Indeed, we have a problem here. The problem is that we set all our procedural texture extensions resolution to 200x200 (a procedural texture has no
resolution), so in your case 200x200 is too different to 1024x1024 (your udim textures resolution).
Tue point here is that the TiledTexture extension HAS resolution, so we have to modify how we handle the texture extensions internally,
and this cannot be done for maxwell 3.
Other channels works right using 200x200, because that resolution is only used to apply a correction to the normal vector generated from the bump texture
(not color, roughness, etc). That correction depends on the texture resolution, and procedural textures has no resolution
(with one exeption: udim textures!).
EXAMPLE:
2. another issue is performance
I tried to make a model with UDIM 1001 - 1005, UDIMs were loaded for R0, R90 in first layer, for Rgh and Opacity in second layer, and in Global bump map channel. Nothing fancy I guess, but when I hit render or FIRE the performance was significantly slower than in situation without usim UDIM.
If I find some free time, I'll create and send proper test scene to development team.
3. last issue I found is related only to Maxwell Studio
Maxwell Studio ignores UDIM textures with value above 1010.
tl;dr Just set offset to -1 in Maxwell Studio for every material which use UDIM. Then you will be able to use UDIMs > 1010.
Here is info and my report I sent to dev team:
...
thanks for info, but I did some small research and found a way how to use UDIMs with numbers above 1010 value inside Maxwell Studio.
When I created a scene in Maya (simple object, one UV at 1015 and second UV at 1033) and assigned textures (test_1015.png and test_1033.png)
it was working. How it is possible that in Maya it works, but not inside Studio ? Hmm... strange.
So I exported this test scenes as .mxs from Maya and opened in Studio, I hit render and voilà it works.
I look closer at material and found what is causing it. Offset !
I don't know how or why Maya set Y offset to -1, but it is only way, currently, how to enable it, when you are creating scenes in Maxwell Studio.
Another point is, that in Maya everything looks correctly when you look at UV coordinates they are both at 0.
I would never found the cause, if I wouldn't open material in Studio. I assume it somehow internally changes this value.
...
If you read till here, thanks. I spend so much time with UDIMs bugs that I think they are not usable in production with current version.
At least, in my case... ufff
- By lebulb