symulating UDIM (Multi-Tiling)

Support Materials and Textures
1

Hi all. I have some questions about UDIM. Firstly, I have mentioned the word “simulating,” in my title because I am not really positive if what I am doing is true UDIM, as I have heard that Blender does not support it. However, I was able to accomplish multi-uv tiling with the Cycles render. Basically, I have made a RGB mix factor image, which is connected in the second uv channel. Using this image, I can separate the ‘R’ ‘G’ & ‘B’ channels and connect the 'G" channel to the mix factor in a mix shader node, which then separates the uv tiles in uv channel 1. The purpose of this is to be able to combine multiple textures in one material. If anyone has done this in UDK, you would be familiar with this technique using a lerp node in the UDK material editor.

I have compiled a sample to explain what I mean…

multi-tile-sample.jpg768×473 32.1 KB

Now that has been said, my first question is, if what I have describe above is really called UDIM, then why would I need the UDIM add-on script? Does this mean that texture painting does not fully support it? Also, why is it not possible with the internal render. I tried many of times, and I was not able to separate between areas that should be transparent, and the rest opaque. Yes, I understand that Cycles can now bake textures, but I could never get it working right, and baking textures is the main purpose I am trying to use Blender for.

could anyone assist me with this?

2

You know, I am a real idiot. For what I am trying to accomplish, which is to bake out the textures, I could just assign multiple materials, as the final results would be to bake the textures anyway. However, in other respects, I still would like to know, if it is really true that UDIM is not supported, then how was it possible for me to have multiple UV tiles. Is my technique somewhat different?

3

You can use multiple UV maps fine, UDIM refers to splitting the mesh across multiple “tiles” within a single map. Like this: https://support.solidangle.com/download/attachments/5800782/uv-texture-editor.jpg?version=1&modificationDate=1363710680000&api=v2

The renderer is supposed to support UDIM by automatically assigning different textures to different UV regions. And ideally reading them all from a single texture node. The UDIM node groups and OSL scripts area basically just hand implementing it within the shader.