fastlane69,

thanks for the tip ... I had already added a phent_setfriction, but could not really see much of a difference.

I was going to experiment with some of the values, but my C-script file just got screwed up, so right now I can't run anything.

Kopitzki,
you are correct, NEWTON handles stacked boxes without any apparent problem. But setting it up is a bit more involved ...

Cheers,
Andreas