About The Structures

Below are facts about the structures to which data are imported or exported.

Check recommended practices, licensing and application protocol requirements in Requirements.

This page discusses:

Product Attributes

Product attributes are mapped the same way at import or export.

  • The title of the product is mapped with PRODUCT.ID.
  • The instance title is mapped with NEXT_ASSEMBLY_USAGE_OCCURRENCE.ID.

Note: The title of the product and of the instances depends on the customization of your installation.

At Import

Below are the rules about imported structures.

  • If the STEP file contains both an assembly structure and geometrical and topological data, the assembly structure and the data will be created and visible in the tree and in the work area.
  • If the STEP file contains only geometrical and topological data, a Product with a single 3D shape representation containing the data will be created and visible in the tree and in the work area.
    Note: As there is no equivalent in STEP, the 3D shape is created with automatic attributes.
  • If the STEP file contains an assembly structure with no geometrical nor topological data, only this structure is created and visible in the tree.
  • When a STEP file references other STEP files, either uncompressed (.stp or .step) files or compressed (.stp.Z) files are expected.

Assemblies

STEP assemblies are mapped with the Product Structure. Geometry can be defined in STEP:

  • In the same file.
  • Or in external files (AP214/AP242 ed1 external references mechanism). The files referenced are STEP files. External references are supported with AP214/AP203 ed2/AP242 ed1 only.
    Notes:
    • In the case of referenced files, those files must be in the same location as the root STEP file, or be accessible via the search order.
    • You can import STEP assemblies, even without any STEP license. However, in this case, only the structure of the assembly is imported, not the geometry.

Examples: The structure imported is the 3D Part, that is a product with an aggregated 3D shape representation.

  • STEP file containing a product structure with one child.

  • STEP file containing a product structure with 2 instances of the same product at different levels.

  • STEP file containing only one part.

  • STEP file containing a product structure with one child and an intermediate part.

Assemblies Referencing 3DXML

When a STEP file references a 3DXML file, it is converted to a product referencing a visualization representation.

At Export

Below are the rules for exported structures.

  • You export the final construction object, i.e. the whole specification tree and its history up to the feature at the bottom of the specification tree and not the current feature. Delete unwanted features located after the one you want to export.
  • If you export a 3D shape representation, the STEP file (xxx.stp) will contain a product, the name of which is the name you have chosen for the export STEP file (xxx).
    Note: Since 3D shapes have no equivalent in STEP, only the geometry is exported. 3D shape attributes, including 3D shape name, are lost in STEP.
  • If you export a product, the STEP file will contain the same product structure (product + geometry).
  • Export of the description to STEP occurs only for products. Exporting to STEP from a 3DShape does not ensure that the root node and its data are exported: a fake product is associated to the representation in the STEP file.
  • When exporting to a STEP file referencing other STEP files, the number of files generated is the same, whether you have selected STEP (*.stp) or STEP (*.stp.Z).
  • STEP exports the .model files referenced by a product.

The following structures are supported:

  • A product containing a 3D shape representation,

  • A product containing a 3D shape representation and a product that contains a 3D shape representation,

By default, when a product contains several 3D shape representations (multi-representations) only the first one is exported, in the case below, only RepresentationA will be exported.

Select Export all visible 3DShape Representations of the Reference to export all visible 3DShape representations of the reference.

Important:
  • The 3D Shape organization is not kept, as all 3Dshape representations are merged in a single one.
  • When a product contains both tessellated and exact 3DShape representations, only the exact 3DShape representations are taken into account.
  • When this option is selected:
    • 3D annotations under Export is set to None.
    • Composites under General is ignored.
    • Persistence export mode disables this option.
See also Flexible Assemblies and Visibility of Instances in Assemblies below.

Assemblies Referencing a Visualization Representation

When a product references a visualization representation (and not an exact one), the conversion generates an assembly STEP file and a 3DXML file, referenced by the assembly STEP file.

Visibility of Instances in Assemblies

When assemblies contain several instances of a product, their visibility status is exported as follows.

  • ProductA contains Product1, Product2 and Product3 that are visible in all instances of ProductA,

    At export, one ProductA is created, that is instantiated several times:

  • ProductA contains Product1, Product2 and Product3 that are not all visible in both instances of ProductA:

    Several products are created from ProductA, one identical to the initial ProductA where all sub-products are visible, others, suffixed _n. that contains only the visible sub-products, each product being instantiated once.

Notes:
  • A new product is created for each instance with overloaded visibility, even if they are identical, whereas only one is created for all the instances without overloaded visibility.

    results in

  • The suffix is incremented according to the needs.
  • The BOM is not kept.
  • See the Nested Assemblies export options for limitations.

Assemblies with Overloaded Instances

Allows you to overload attributes of instances inside a product, e.g.:
  • The color of an instance
  • The visibility of an instance
  • The relative position of an instance inside the product (flexible assemblies).
Note: Regarding Product Graphical Properties
  • When you start the export from an interactive sessions, the result is always WYSIWYG, no matter wich menu item you may have selected.
  • When you start the export from a non-interactive command (CAA command, batch monitor, ...) the Product Graphical Properties (in this case the visibility status) taken into account are the saved ones. In that case, to export graphical properties previously modified in an interactive session, do not forget to select Keep Modifications before hitting Save.

As of today, the STEP standard does not fully support the overloading of instance attributes. As a consequence, STEP export is done as follows.

  • The overloaded instance attribute is the color.
    • The color of instances is not taken into account.
    • The BOM is kept.

    In the example below, there are three instances of Product2, two of them with color overloading. After an export/import loop, the BOM is retrieved, but the color overloading is lost.

  • The overloaded instance attribute is the visibility.
    Note: As the visibility status is not taken into account when the check box Export also NoShow entities is selected, the following applies to the other case, when Export also NoShow entities is not selected. See About Visibility for more information.

    At export, a product with overloaded visibility of instances is considered as a new product, having the same name with a suffix_1, _2, ...

    In the example below, there are three instances of Product2, made of PartA and Part B, two of them with visibility overloading, i.e.

    After an export/import loop, the result has the same geometry and appearance, but the BOM has changed. There is only one instance of Product2, and two instances of new products.

    See the Nested Assemblies export options for limitations.

  • The overloaded instance attribute is the position - flexible assemblies.

    When you export a flexible assembly (i.e. a product containing instances movable from their position in their reference product), these instances are considered as instances of a new product. This new product receives the name of the product with a suffix _1 (the number is incremented if there are several flexible instances of a product).

    Note: The BOM is not preserved because there is an additional products for each flexible instance in the exported assembly.

Visibility of Representations

Preferences are not taken into account when exporting content. When a representation is not visible, it is considered as inactive, and thus not exported.

Assemblies Options

Assemblies export options can be activated under Export,in the STEP Exchange section of the Preferences.

Available options are:

    • One STEP file creates one STEP file only, that contains the structure and geometry of the components.
      Note: This option does not support AP 242 XML format.
    • External references to STEP creates:
      • One STEP file containing the whole product structure of the assembly,
      • And a STEP file for each leaf component (parts). The STEP file names, for each component, have the same name as the components. The structure and the component STEP files are generated in one shot, in the same location.
      A STEP file cannot refer to a STEP assembly file.
    • Global nested assembly creates a set of STEP files:
      • One STEP file for the root product (having the name you have entered).
      • STEP files for intermediate sub-assemblies, if any (having the name of the corresponding sub-products).
      • STEP files for each leaf component (having the name of the corresponding parts).
      Notes:
      • Two STEP files are created for each product that has both children and representations.
      • For AP 242 XML files, two files are created for one part: One STEP XML file and one STEP file.
      Important: To avoid generating STEP files with identical names, make sure all products have an unique name.
    • Partial nested assembly is similar to Global nested assembly but takes only the root product into account. It creates one assembly STEP file or one part STEP file.
Notes:
  • You are responsible for the consistency of the set of STEP files generated. Global nested assembly creates a consistent set of STEP files. It is your responsibility to update this set of files when using the Partial nested assembly option.
  • We recommend that you name the exported STEP files with the name of the exported product.
  • To avoid naming inconsistency, when the options Global nested assembly or Partial nested assembly are selected, the visibility status of instances in the assembly are not taken into account: The instances are exported as visible whatever their visibility status.
  • The flexibility of assemblies as described in the STEP export section is not taken into account.
  • If Geometric Validation Properties (GVP) is selected, the assembly STEP files do not contain geometric validation properties.
  • If Assembly Validation Properties (AVP) is selected, the assembly STEP files contain the assembly validation properties.
  • Dynamic Licensing: If you release the STEP license and you access the STEP options panel, the export assemblies options may change. In this case, when you recover the STEP license, you have to go back to the STEP options panel to restore the required values.