Object Type in the To Do List: Bracket plate system.
Meaning: Smart 3D cannot define a plane based on the inputs. This problem might occur for an existing bracket plate system if you modify or delete the supports.
Verify all of the supports for the bracket plate system.
Check for any missing supports or any supports on the To Do List.
Recompute the object.
If proper inputs are provided and the problem persists, report steps taken to your support group.