CIS/2 support in Bentley products - white paper

Summary

Bentley Systems Inc. is committed to supporting CIS/2 standard as the primary format to exhange structural steel data. The first application to support CIS/2 will be Structural for Microstation Triforma ("STF"). This paper discusses details specific to how the CIS/2 translator  will work. This is not cast in stone; feedback is welcome. S/w vendor cooperation in making CIS/2 a success is eagerly solicited.
 

Exported data structure

Exported are:
assembly_map
assembly_design_structural_member subtypes
element_node_connectivity
element_curve_simple
node
section_profile and entities necessary to identify it as a catalog reference
units
global_units_assigned_context
Units are assigned once per file through the global_units_assigned_context mechanizm. Explicit profile definitions, if/when these are supported, are expected to be based on the same unit definitions.

Structural members are subdivided (currently only in structural analysis export mode). The subdivision info is saved in the assembly_map. assembly_design_structural_member.item_name ( inherited from structural_frame_item) reflects the name of the beam in TFS; element_curve_simple.element_name (inherited from element) is set to the same with :<subdivision index> appended.

In all cases, instances of assembly_map and assembly_design_structural_member subtypes are generated.

Section profile name is identified by item_reference_standard instance referenced by item_referenced_assigned that also references the given section_profile instance. Note that section_profile.item_description (inherited) is also set to profile name. Unlike the former, this is not guaranteed to remain so in the future.

Profile tables are currently identified as Triforma tables. They are based on national standards. Reliably identifying catalogs appears to be an unresolved issue. As soon as the agreement on catalog identification is reached among CIS/2 community, we will change that to reflect the agreed upon method.

Naming of node and cartesian_point instances is generated by the export utility and is purely informational. It does not carry any info meaningful to Triforma.
 

Data structure expected by import utility

.. is similar to the discussed above. We will appreciate a "changes only" mode available in the exporting applications (i.e. an option to export only changes that your application made).
 

Revision history

02/24/2000    Nikolay G. Shulga, 1st draft