I really don't know what prompts me to post this. Except that there are two or three people who might get some use out of it.
OK, in the past, there were only two ways to get layouts from your 3D model: Unroll and Smash. Unroll is easy and works on parts that are already 2D. Smash takes a lot of playing around with. Actually you need to smash U and then smash V and try to match corners and edges to get something to work.
For those of you w/o Rhino, and I have no idea why you might still be reading at this point, Smash was the only way to get surfaces curved in more than one axis to lay out.
Well, a couple months ago, Rhino released SQUISH. This is a MUST GET if you don't have it. Their recommendation is now to ignore Smash and use only Squish.
OK, but... Squish has its quirks. When you use it, you will discover that your corners (End to Rhino afficianados) doesn't work because somehow Squish breaks up edges into billions of bitty pieces and the corners are like stars. So what to do...
Here is my current solution. BEFORE Squishing, I mark the corners with points. Sometimes I put down lines (DupEdge) also. Then Squish - I have not found any of the options useful so far so just hit Enter - with the points included. OK. Now I can use the points to align the part and to help define the edges of the squished piece.
Dunno if this makes sense or helps but it took me awhile to figure it out...