Emmanuel -

Um... never mind.

After a day spent fighting the three problems I mentioned earlier, for the last two days I've had no trouble at all with SH3D. (Well, the 3D window seems to take a little longer to update than previously -- but, then, my plan is significantly larger.)

My best guess is there were conflicts among libraries in use. I'd started out running 5.2 beta 1 before installing 5.2 and, shortly after, 5.2a. At that point I started noticing the delays and hangs. Because of the surface normal issues, rather than leave the PC on overnight to render a complex scene, I powered it off; when I returned to it the following night, everything was OK. I can only assume the reboot cleared out whatever internal struggle had been going on.

This raises the question whether the surface normal problems I found (and painstakingly documented [:|]) actually exist. I'll dive back in later today....

Thanks,
maz