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- Create a new MagicDraw project. Add the Syndeia profile to your SysML model, as shown in Section 2 here.1.
- Launch the Syndeia Dashboard and access the NX CAD model (.prt) 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).
- Expand the prt file to view the NX model structure. This will initialize a NX session if this is the first time you are accessing NX models after creating/opening your SysML project. Once the NX session is initialized, you will see an assembly icon (for NX assemblies) or a part icon (for NX piece parts) under the prt file, as shown for the toycar_assy assembly model under toycar_assy.prt file in Figure 109 below.
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- Expand the NX model to view the assembly structure, as shown in Figure 110. You can also expand any other NX prt file to view the part/assembly structure, as shown for the toycar_axle_assy.prt file below. You can right click the prt file or the NX CAD model in the RHS pane and select Open, as show in Figure 111 below.. This will open the CAD model in NX, as shown in Figure 112 below.
Figure 110: Expand the NX model to view the assembly structure
Figure 111: Right click on the prt file or NX model and select Open
Figure 112: Syndeia opens the NX CAD model from the Dashboard
- Select Model Transform connection type in the middle panel and drag and drop the NX model (e.g. toycar_assy) from the RHS pane to a SysML package on the LHS pane, as shown in Figure 113 below.
Figure 113: Drag and drop the NX model to a SysML package
- Select Model Transform connection type in the middle panel and drag and drop the NX model (e.g. toycar_assy) from the RHS pane to a SysML package on the LHS pane, as shown in Figure 113 belowpanel.
Figure 114: Drag and drop the NX model to a SysML package - Select Yes at the prompt.
Figure 115: Select Yes to confirm generation of SysML block structure from NX assembly structure - This will generate a SysML block structure from NX assembly structure, as shown in Figure 116 below. Notice the generation of block value properties and part properties corresponding to mass properties and assembly components respectively in the CAD model.
Figure 116: SysML block structure generated (LHS) from the NX model structure (RHS)
- Create a SysML block diagram in the SysML tool and drag and drop the toycar_assy block generated in the previous step to the diagram and expose all the part properties and value properties of the toycar_assy block, as shown in Figure 117 below. Now, you can see the details of the block structure generated from NX assembly structure by Syndeia. The toycar_assy block has 4 part properties—3 shown in the parts compartment and 1 shown in an expanded form (FRONT_AXLE). The semantic mapping from NX CAD assembly structure to SysML block structure is as follows:
NX part or assembly -> SysML block
NX part or assembly mass properties -> SysML block value properties
NX assembly component -> SysML block part property with an association block
NX part feature -> SysML block and part property (optional)
NX feature expression -> SysML value property (optional)
Figure 117: SysML BDD showing the block structure generated from NX assembly structure
- Syndeia generates a SysML block corresponding to every NX CAD part or sub-assembly in the root assembly structure. It applies the NX_Part stereotype to identify NX parts (piece parts or assemblies) and sets the base unit for the part (e.g. mm) in the unit stereotype tag. 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 stereotype applied to the value property, e.g. unit for mass is kg (as shown in Figure 118).
Figure 118: SysML blocks are generated for every NX part/assembly in the assembly structure.
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 (FRONT_AXLE) from the parent assembly block (toycar_assy) to the child part or sub-assembly block (toycar_axle_assy). Second, it creates an association block for the composition (part property) relationship that stores 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 NX_Component stereotype to association blocks, as shown in Figure 117. The transformation that places the component in the assembly is expressed in terms of a translation vector and a 3x3 rotation matrix, as shown in Figure 117. - Similar to all drag and drop operations, Syndeia generates connections between SysML blocks and the NX 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, as shown in Figure 119 below. Users can invoke compare and sync operations by right clicking on one or more connections.
Figure 119: Invoke SysML-NX compare and sync operations using connections generated by Syndeia
Currently, the following are supported in the compare and sync operations.- Compare only compares the mass properties between the SysML blocks and NX parts/assemblies.
- Sync from Target > SysML only updates the mass properties in the SysML block from the NX 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.
- Syndeia provides additional options to bring features on CAD parts and expressions/parameters on features to the SysML model. You can select the following 2 NX settings in the Settings tab—Get features of NX parts and Get expressions (parameters) of NX parts—and select Apply, as shown in Figure 120 below.
Figure 120: Syndeia provides additional options to bring features and expressions (parameters) from NX.
- If these settings are applied, then dragging a NX model to a SysML package (as shown in previous steps) will also generate SysML blocks corresponding to part features, and block value properties corresponding to feature expressions/parameters. The NX_Part_Feature stereotype is applied to each block corresponding to a part feature. As shown in Figure 121 below, the toycar_body block has 7 features—5 shown in the parts compartment and 2 shown in the expanded form. A SysML block, e.g. Extrude(4), was generated for each feature under the toycar_body block—see model containment tree on LHS—and a part property relationship was created from the toycar_body block to each of the feature blocks. The Extrude(4) feature block has 2 value properties indicating the extrusion depth of 23 mm.
Figure 121: Feature blocks and expression value properties generated from a NX part
Generate NX CAD part with features from a SysML block structure
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- Open the My System Part Features model in MagicDraw. Open the Part feature decomposition BDD under the Parts package, as shown in Figure 123 below.
- Right click on the Parts package in the SysML model containment tree and select Syndeia > Dashboard menu. This will launch the Syndeia Dashboard. Go to the Connection Manager tab, as shown in Figure 122 below.
Figure 122: Drag SysML block with feature definitions (LHS) to a folder (RHS) to generate NX CAD model
Figure 123: SysML block structure with feature definitions for generating NX CAD model with features
- In the Syndeia Dashboard, select the connection type in the middle panel as Model Transform and drag-n-drop the My System block from the SysML tree (LHS) to a folder on your local file system (RHS), as shown Figure 122.
- Select the option to Generate NX CAD model in the dialog box, as shown in Figure 124 below, and then click Yes to generate the NX CAD model, as shown in Figure 125.
Figure 124: Select option to generate NX CAD model
Figure 125: Click Yes to generate NX CAD model
- This will generate a NX CAD model with the same name as the SysML block (e.g. My System), as shown in Figure 126 below.
Figure 126: NX CAD model MySystem generated from SysML block structure
- Right click on the My System.prt file or My System NX model in the Syndeia Dashboard and select Open. This will open the CAD model in NX, as shown in Figure 127 below. Note that 7 features have been generated in NX (as highlighted) from the 7 feature definitions in the SysML block structure (Figure 123). The part property names for the feature definitions in the SysML model have been used to name the features in the NX CAD model, e.g. "my earth" for the Sphere feature used in My System.
Figure 127: Open NX CAD model from the Syndeia Dashboard
Follow the general rules below to create your own SysML model for generating NX CAD parts with features. These rules are also mentioned in a note form in the SysML BDD Part::Part feature decomposition in the My System Part Features SysML model.
- Define a block to represent the parent part. Apply the NX_Part stereotype to this block and populate the unit tag , as shown in Figure 128 below (allowable values are mm and inch). The units apply to everything in the part, including computed parameters such as volume and bounding box.
Figure 128: Populate the unit tag of the NX_Part stereotype to specify the base units for the NX part
- Create blocks to represent the primitive features. Allowable names are - Point, Line, Plane, Cuboid, Cone, Cylinder, and Sphere. Apply the NX_Part_Feature stereotype to these blocks, as shown in Figure 123.
Create and populate (default value) the value properties of the feature blocks, as shown in Figure 123. The names of value properties for the feature blocks must be exactly same as in the My System Part Features model (Figure 123).
Highlight color light yellow For steps 2-3 above, it is recommended that you copy the feature blocks in the example model My System Part Features in your own SysML model and then modify the value properties for the feature parameters, as needed. - Create part properties (composition relationships) from the parent part block to the feature blocks, as shown in the My System Part Features model (Figure 123).
- Name the part properties with names that are relevant to your domain. These names will be used to set the feature names in the NX CAD model, as shown in Figure 127.