Hi Randy, it looks like the difficulty is that the adjacent surfaces have their underlying surfaces extending out a little bit from the original trim boundary, like here:




So those probably need to be trimmed to an isoparm, not directly to the other surface's edge. Or it might work to get the right edge after untrim if you run ShrinkTrimmedSrf on the outer ones before untrimming. I'll take a look and see if I can get this done.

- Michael