2.61 cycles: multiple UV maps on single object?

Probably a very simple question but I found no clear answer. How can you get Cycles to use multiple UV maps on a single object? In 2.61, you can use (as was always the case) multiple UV maps as found in the object data tab, so one object can use multiple materials, each assigned to its own set of faces and each material can have its own UV map.

Consider first Blender Internal. Highlighting a single UV map in the object data tab shows that selected UV map applied to the object in a viewport, when in textured view. Clicking the little camera to the right of the name of the UV map reveals a tip, “select the map as active for rendering.” However, I haven’t found what this does using Blender Internal, as it does not change the textured view. Furthermore, it does not seem to effect the final render because in the case of an object with three materials and three separate UV maps, all maps and materials render correctly regardless of which camera is highlighted in the UV maps panel of the object data tab. The result is that BI works fine when applying multiple materials and UV maps to a single object.

Using cycles, this same arrangement will not permit multiple materials to render on an object. After converting each material to a proper node-based material, cycles will render only the image belonging to a single UV map, and this appears to be based upon which small camera is highlighted in the UV maps panel. No matter what I try I cannot get more than one material rendered with a correct UV map. Other materials on the object will render, but the image mapped upon the faces assigned to that material will not follow the UV mapping associated with it. Instead it renders the faces as if the default mapping applied, the one you get when you “reset” the unwrapping on a mesh.

To recap:

an object with three materials, each with a set of assigned faces and a separate UV map for those faces

in BI
material 1 with UV map 1, has little camera highlighted in UV maps tab
material 2 with UV map 2
material 3 with UV map 3
all render correctly no matter which UV map has a highlighted camera

in Cycles
material 1 with UV map 1, has little camera highlighted in UV maps tab
material 2 with UV map 2
material 3 with UV map 3
only the faces assigned to material 1 render correctly; highlight a different camera in the UV maps tab, and then that material alone is mapped correctly
other faces show the materials’ image textures but do not follow their UV maps

Haven’t looked at this thread for a few weeks, but I can’t wait to try your solution, Merci bien, mon ami.

thezodiac is GODLIKE. That worked perfectly. Many thanks.

See also Greg Zaal’s VFX tutorial at Blender Coockie:
http://vimeo.com/34581107
around minute 42
You can even define multiple materials for parts of your mash of the same object. This is seen in the same tutorial however not further explained.

"thezodiac is GODLIKE. "…what was the solution…? I’m dying to hear.I trying for days to uv map different images with different uv maps to one mesh.
Please share your wisdom
Thanks
Alex

Yes use an attribute node with the name of the uv map in it not a vector node…

Yes use an attribute node with the name of the uv map in it not a vector node…

For a demonstration check thus tut out: http://blenderartists.org/forum/showthread.php?245468