ReadonlybuiltWhich builder's tree rays see now, or null (none yet, or a mesh only merged instances use).
ReadonlydeformingAdded as deforming (SceneTrees.setPose, SceneTrees.rebuild).
ReadonlyfallbackWhy no GPU tree was (or will be) used, or null.
ReadonlymaxReadonlymergedThe mesh's triangles live in merged group mergedInto (and it has no tree of its own).
ReadonlyplacementWhere the tree sits in SceneTrees.buffers, when placed.
One mesh's (or merged group's) tree, for tools and tests.