Howdy Gang!
I'm helping a fellow @ RC Groups sort out some structure, and PowerPack just blows away the competition! (SCAD)
I have never had any STL files 'reported' for not working thanks to Tim Olsen and his work @ PunchCAD/ EVO Software!
 I'm running on High Sierra, and when doing any heavy rendering, ignore your Mac, just turn on a video game, as V11 and High Sierra are doing just fine!
https://youtu.be/nwtsweqM6r0

Howdy Gang! I've learned today that this is what happens when a Mac pulls in a non Binary stl file when it was a Windows construction! It's proof when we export for 3D Printing, to go "binary"
Johnny