Why shouldn't join() operate on animated nodes?

[rawnsley]

The join transform skips nodes that are animated, but I can't quite see why. The primitives are all going to be in lock-step with one another for any animated node transforms aren't they?

[donmccurdy]

I think you're correct that given an animated node, there's no reason we couldn't join two or more mesh primitives attached to that node.

Currently the join() function operates by inspecting all sets of nodes sharing a common parent node, and joining eligible primitives at that 'level' of the node hierarchy. Since an animated node's primitives can't be joined with those of its siblings, that node just gets skipped entirely. I'd be open to PRs making join() less conservative about this, though!