I’m trying to create a polygroup using Select Rectangle - but I can’t get the right set of polys in one go. Can I add to the selection? I thought that was the default behavior - but when I do a second Select Rect selection, it simply replaces the first one rather than adding to it.
Why don’t you just paint a mask and then hit Ctrl+W or go to the Polygroups panel and click Group Masked to create a Polygroup.
Or, if you want to do it with the selection tool, select a larger section to start with and then chip away at it by subtracting out the polys that you don’t want in the Polygroup.
I found once out, that you can sometimes (with very detailed faces) more easily use Zmodeler to create polygroups:
just Alt+drag