Just a question I haven't found an answer to in the XSI help yet:

How do you coopy the UVs of a number of polygons at once in XSI? At the moment I can only copy the UVs of one polygon at a time. Is it something to do with creating clusters?

you can select the UVs in the textureeditor and select edit>copy UVs, then select the other (exactly similiar) grpoup of polygons and click edit>paste UVs but this doesnt always work

in case you work with clusters(and multiple texture projections):NEVER do that!

Oh...ok so there's no other way to do it? Sadface. Ah well this thread can be locked then.

if you made several clusters each with own texture-projection you can try to select the proper cluster (click the cluster button on the right and select a cluster), copy the UVs, all polygons of the cluster on the second model and paste the UVs

this will not always work, because even transfering UVs between two models with one textureprojection doesnt work sometimes

From the XSI docs with regards to the UV copy function in Texture Editor
So yes in that regards XSI fails.

Now if you can get the two desired projections close in shape and size to each other then move the one on top of the other you can use the Match fuunction which matches the the selected UVs to the ones that are underneath it.