Great news! My Playground scene is working flawlessly now.
THE SOLUTIONS:
-
@bghgary: use
.setParent()and.useRightHandedSystem = true -
@carolhmj: bake the mesh transforms and discard
__root__(requires async function) - There were some remaining mesh positioning bugs, but switching to AmmoJS fixed them. Yay!
In conclusion: don’t use abandoned physics engines like poor CannonJS… (cannon-es is fine)

