Sounds like maybe there is a race condition that causes the ModelEntityItem to sometimes not be properly flagged for addition into the physics simulation. Here is something to try: when a “static-mesh” entity incorrectly loads (visible but no collision shape) try moving it’s position a little bit --> this will put the entity on a list of objects that need to be updated in the physics engine, and may trigger the shape to be built. If this is a valid workaround then it must be a race and I’ll have to find it.
Meanwhile, not the same bug but somewhat related…
(1) I think there is a bug where the existence of a non-empty string in the compoundShapeURL property when the shapeType is NOT set to “compound” can cause a problem where the model does not render when this menu option is enabled: Developer --> Physics --> Draw Collision Hulls. I have a fix for this one in an unfinished branch.
(2) Also, I’ve seen a problem where if a ModelEntityItem is given a bogus compoundShapeURL property (to a link that doesn’t exist) then the whole model might never render at all, which would also make it never collide. This needs to be fixed and I’m going to try to do so in one of the projects I’m working on but in the meantime for best results: clear out unused “compoundShapeURL” properties (e.g. when NOT using “compound” shapeType).