Thank you all for the creative solutions! sdmitch's solution for any mesh worked great. These others have me loading up on additional plugins.

Thank you both. I'll be watching for that one.

Will the plugin work with an already triangulated surface?

Say I have imported and triangulated a set of XYZ data, and wish to turn it into a solid group like your final product, with vertical sides and a horizontal bottom. Is that possible?

Thanks TIG.

I have been searching the SCF, other forums, and plugin libraries fairly extensively, and sdmitch's solution is what I refer to the in the last paragraph on adding the skirt. Since my surface is not Google Earth terrain, his plugin would not handle the surface.

I've been using search terms like this post subject or "push pull multiple faces" or "extrude multiple surfaces". I've found answers for multiple faces that are separate, but not if they are joined in a triangulation like mine. If you have any suggestions for SketchUp lingo I'm missing, I would be grateful.

I've been trying for some time to find a way to create a solid group with vertical sides, a horizontal bottom, and an irregular triangulated top.

I import a series of XYZ points and then triangulate the surface. I'd like to turn that into a solid so that I can then use the SU Pro solid tools to manipulate it.

In the past, I've drawn vertical lines down from each vertex on the perimeter, and then manually connected each one, taking the time to go "inside" the solid and erase any internal faces that were generated. This was reasonable for small models, but now the number of perimeter vertices is high (>500) and this seems like a unnecessary effort.

I've tried the "projection extension" toolbar using "extrude multiple faces along Z", but that created many internal faces that would have to be removed. What I'm looking for is similar to adding a skirt to GE terrain, but doesn't work with just a collection of faces.

Any suggestions?