@unknownuser said:
Integrated Intel graphics haven't had a great track record as far as adequate OpenGL support although that's been more of a problem with Windows than Mac. Apple seems to do a better job of not breaking the drivers that Microsoft. Most Mac users seem to manage OK with Intel graphics.
At this stage, considering your application, SketchUp 2018 Pro would be the way you'd need to go so you might as well dive in.
Thanks. Assuming I can still get a free version, I think I'll just download that and see how it works. If it's OK, I'll switch to Pro. I need Pro for it to be useful for me, but not sure I want to shell out the $$ if there are going to be problems.