The following requirments must be met in order to stitch shapes to SmartSolids or SmartSurfaces:

• The elements must be shapes or complex shapes.
• All shapes must be planar. In situations where you are using existing graphics to create features, you may encounter non co-planar shapes. Non co-planar shapes are not valid and should be redrawn as planar shapes.
• The shapes must enclose a volume.
• There should be no interior elements such as floors or structures.
• There should be no coincident shapes such as windows and mullions.