I have been browsing for hours at asking all the Maya users i know to answer my question but I seem to be getting nowhere.
I extruded a circle curve on a line to form a tube, this tube i then converted to a Subdiv for further modeling. I then continued to try to apply create a PSD network for this Subdiv but keep getting an error mesage that tells me it is not a valid surface. All the history on the object has been deleted and it contains no static channels, but still refuse to "take" the PSD network.
can you at least apply a material to it, like a Lambert or something?
it may be giving you an error because its trying to handle the material in the wrong way. if this is the case (unless you're using mental ray) try useing a standard file texture node instead of a PSD file texture node. (mental ray is picky about what files it loads in the file nodes), if it still gives you problems try saving out a test JPEG file and use that in a file texture node. you might see that its another problem entirely.
you are using mental ray then try to directly connect the file texture node to the color channel in the hypershade by right click dragging the output of the file texture node into the color input of the material shader.
also if you are attempting to apply the material to the object while in polygon proxy mode the information will not carry over to the actual SubDiv surface, the proxy is just used to edit the points not the materials applied, you need to switch to "Standard" mode and re apply.
I know that you can change the material of the proxy mesh however [in versions 8.0 and up] when you change back to standard it deletes the mesh and removes all materials applied. I haven't tried to apply texture maps.
I couldn't seem to replicate this problem on my own but I hope the solutions i offered have helped.