I can’t believe I have been missing out on this useful technique all this while.
This is most useful when you are using a Layered Texture (e.g. to plug into the color node of your MR / Vray shader), and would like the texture file nodes of each layer to be affected by a different UV layout.
Here’s a tutorial by Parker Davidson on Lesterbanks (a place for great 3D resources!) that gives a good explanation of how to use mutiple UV sets together with the layered texture.
In summary, to create mulitple UV sets for a single object,
– Go to the UV texture editor, under the Polygons menu > Copy UVs to UV set > Copy into New UV set (or just create an empty UV set)
– Name your UV sets, and you can switch among them under the UV Sets menu
– You can freely edit the UVs of each set or reapply certain UV mappings without affecting the other sets.
To link a texture file node to a specific UV set:
– Go to Relationship Editor > UV Linking > Texture-Centric
– Select the file node on the left, select the corresponding UV set you would like to use on the right
How is this useful?
Imagine that you are adding in details to a just a small corner of your object. Your texture resolution has to be really big in order for the details to be sharp. However, if you use a layered texture to add in the details to your base color / texture, by using multiple UV sets, you can scale up one of them without affecting the rest and thus use a much smaller texture resolution. You can now also have the freedom to move the details around by shifting the UVs in its UV set.