I'm assuming this is a bug-or is it a limitation of the way Sub-D's are implemented?
When in global mode, Octane only renders the cage, regardless of the Octane Level chosen. Switching to Movable Proxy fixes it, but this is a significant performance hit to those of us whose scenes mainly comprise sub-D meshes.
Subdivision bug in global mode
Moderator: JimStar
This is not a bug.
You can't have different subdivisions of different parts of one common global mesh. If your objects are "Global" - they all are collapsed into one big global mesh during rendering. After that your "separate" object does not exist anymore as the separate object - it is just the part of one big mesh and it can't have its own subdivision, as the subdivision algorithm will always subdivide it together with the rest of this big mesh making one big mess instead of just this object's subdivision.
You can't have different subdivisions of different parts of one common global mesh. If your objects are "Global" - they all are collapsed into one big global mesh during rendering. After that your "separate" object does not exist anymore as the separate object - it is just the part of one big mesh and it can't have its own subdivision, as the subdivision algorithm will always subdivide it together with the rest of this big mesh making one big mess instead of just this object's subdivision.