Although the iTwin capabilities are very powerful, and can accommodate large and complex models, there are some limitations and some configurations that may be problematic, especially when creating a RAM Structural System model from an iTwin. Here is a partial list of the more common conditions that may cause problems:

• When importing into the RAM Structural System, the program requires that the iTwin model represents a building structure (distinct floors, nominally vertical columns – although sloping columns are permitted, etc.). The floor and roof framing must be able to be recognized as associated with distinct floor layouts.
• Miscellaneous framing members such as stairs and wind girts at intermediate levels will not likely import correctly, and should be set to Rejected in the iTwin Analytical Synchronizer before importing into the RAM Structural System model.
• Some configurations of sloping framing may be unresolvable and will require modification in Modeler. For example, framing other than braces that slopes from one level to another is not permitted in the RAM Structural System.
• Some configurations of cantilevers may be unresolveable and will require modification in Modeler.
• Parametric and table sections are supported for steel elements. Not all built-ups are interchangeable.
• Only rectangular and T sections are supported for concrete beams.
• Only rectangular and circular sections are supported for concrete columns.
• Kinked or curved members are imported from their end points as a linear member.
• Composite beams stud values are exported only.
• Camber values are exported only.
• Only rectangular wall openings are imported. If an opening is not rectangular a bounding box is imported.
• Only rectangular and horizontal isolated foundations are imported.