Generating SysML block structure from Creo CAD model

The process of generating SysML models from external models (e.g. PLM and CAD) follows a common pattern. Follow the instructions below to generate SysML block structure from Creo CAD assembly structure (.asm file), or piece part (.prt file).

The Creo CAD model used in this illustration is the race car model available from PTC with the Creo training. See Creo model 1_formula_sae_racecar.asm shown below.

 

  1. Create a SysML model with an empty package named Racecar. Add the Syndeia profile to your SysML model.
  2. Launch the Syndeia Dashboard and access the Creo CAD model (.asm) file, using a repository link pointing to the section of your local file system where the CAD model is located (see Section 2.1 for adding a repository link).
  3. Expand the .asm file to view the Creo model structure. This will initialize a Creo session if this is the first time you are accessing Creo models after creating/opening your SysML project. Once the Creo session is initialized, you will see an assembly icon (or a part icon when expanding Creo .prt file).



  4. Expand the Creo model to view the assembly structure. You can see all the components of the race car assembly in the Syndeia Dashboard, similar to the Creo model tree.


     
  5. Select Model Transform connection type in the middle panel and drag and drop the Creo model (1_FORMULA_SAE_RACECAR) from the RHS pane to a SysML package on the LHS pane.
  6. Select Yes at the prompt.


     
  7. This will generate a SysML block structure from Creo assembly structure.


  8. Create a SysML block diagram in the SysML tool and drag and drop the 1_FORMULA_SAE_RACECAR block generated in the previous step to the diagram and expose all the part properties and value properties. Now, you can see the details of the block structure generated from Creo assembly structure by Syndeia. The 1_FORMULA_SAE_RACECAR block has 17 part properties—16 shown in the parts compartment and 1 shown in an expanded form (CHASSIS). The semantic mapping from Creo CAD assembly structure to SysML block structure is as follows:

    Creo part or assembly -> SysML block
    Creo part or assembly mass properties -> SysML block value properties
    Creo assembly component -> SysML block part property with an association block
    Creo parameter -> SysML block value property (optional)

     

    Syndeia generates a SysML block corresponding to every Creo CAD part or sub-assembly in the root assembly structure. It applies the Creo_Assembly stereotype to identify Creo assemblies (.asm files) and Creo_Part stereotype to identify piece parts (.prt files). The mass properties of the part or assembly are generated as value properties. This includes mass, volume, density, surface area, center of gravity, and the coordinates of the lower left corner and upper right corner of the geometric bounding box of that part/assembly. The units for mass properties are assigned to the unit tag of the Creo_Mass_Property stereotype applied to the value property, e.g. unit for mass is kg.



    A CAD assembly is made of up of components, each of which are usages of a part (or sub-assembly) in the context of that assembly. Syndeia generates two important elements for assembly components. First, it creates a part property relationship (CHASSIS) from the parent assembly block (1_FORMULA_SAE_RACECAR) to the child part or sub-assembly block (toycar_axle_assy). Second, it creates an association block for the composition (part property) relationship which is intended to store information regarding the placement of the component in the assembly, specifically the transformation from the child part (or sub-assembly) co-ordinate system to the parent assembly (or global) co-ordinate system. Syndeia applies the Creo_Component stereotype to association blocks.
     
  9. Similar to all drag and drop operations, Syndeia generates connections between SysML blocks and the Creo CAD parts/assemblies. These connections are stored in the SysML model. You can view the connections organized by the SysML model in the Connection Browser tab or as a flat list in the Connection Summary tab. Users can invoke compare and sync operations by right clicking on one or more connections.



    Currently, the following are supported in the compare and sync operations. 
    • Compare only compares the mass properties between the SysML blocks and Creo parts/assemblies.
    • Sync from Target > SysML only updates the mass properties in the SysML block from the Creo part/assembly
    • Sync SysML > Target is not supported. This use case is not a high priority for system engineers since they usually do not modify existing CAD models directly. Mass properties in a CAD model are computed from the geometry and hence they are read-only properties.
  10. Syndeia provides additional options to bring parameters from Creo models (parts/assemblies) to the SysML model. Select the Get parameters of Creo models setting in the Settings tab and select Apply.

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