STEP: Import

This task shows you how to import to a CATPart or CATProduct document
the data contained in a STEP file. 

It is also possible to insert a STEP file as an existing component in a CATProduct. 

The level of Recommended Practices published by the CAx Implementor Forum applied by the translator at import and export are the following :

See also:
CAx Implementor Forum
http://www.cax-if.de
http://www.cax-if.org
Check the license requirements for STEP!
The table entitled What about the elements you import ?
provides information on the entities you can import.
You can find further information in the Advanced Tasks:

and in the Customizing STEP Settings chapter.

Statistics about each import operation can be found in the report file and the error file.


  1. Depending on your configuration:

    Click the Open icon  or select the File > Open command.
    The File Selection dialog box is displayed.
    or

    Insert/Existing component command.
    The File Selection dialog box is displayed.

  2. Select one STEP format from the list (*.step, *.stp, *.stpx, *.stpxZ, *.stpZ).
    *.stpx, *.stpxZ are STEP XML files.
    *.stpxZ, *.stpZ are STEP compressed files.
    All the files of the type selected are now displayed.

  3. Select the file of your choice (MoldedPart.stp, in our example) and click Open.

    A progress bar is displayed.
    You can use the Cancel button to interrupt the transfer at any time.
    The conversion is then interrupted (after the processing of the current independent entity) and the partial conversion already performed is displayed in the V5 session.
What is then displayed depends on the contents of the STEP file.
  • Compressed STEP files are uncompressed before being imported.
  • For the File/Open command:
    • If the STEP file contains a normalized assembly structure,
      a CATProduct document is created.
    • If the STEP file does not contain any geometrical and topological data,
      the components will be visible only  in the Specification Tree.
    • If the STEP file contains also geometrical and topological data,
      all the components will be present in the Geometry Space and in the Specification Tree. 
    • If the STEP file contains only geometrical and topological data, a CATPart document is created.

The geometrical elements of the faces, which could not be transferred,
are created in the NO SHOW space. In the NO SHOW space, you can
visualize the Surface supports and the 3D Curves).

  • For the Insert/Existing component command:
    • if the STEP file contains no assembly information, it is converted to a CATPart,
    • if the STEP file contains assembly information, it is converted to a CATProduct
      referencing several CATPart documents.

The resulting document is inserted in the current CATProduct document,
and the graphic window is updated (specification tree and geometry).
  • The reference to the STEP file is lost, so any update of the STEP file will have no effect
    in the CATProduct.
 
  • For both commands:
    • The reference planes are hidden.
    • A Geometrical Set is always created. It may be empty:
      • it will contain the valid surfaces imported, if any.
      • it is empty if there is no valid surfaces, e.g. when the element imported is a solid,
        or when all surfaces are invalid.
      • invalid surfaces are sent to a specific Geometrical Set (FaceKO#xxx)
Several STEP options can be customized:

Report file

After the recovery of STEP files, the system generates:

  • a report file (name_of_step_file.rpt) where you can find references about the quality of the transfer 
  • and an error file (name_of_step_file.err) .

These files are created in a location referenced by the CATReport variable. Its default value is 

  • Profiles\user\Local Settings\Application Data\Dassault Systemes\CATReport on Windows (user being you logon id)
  • and  $HOME/CATReport on UNIX.
Always check the report and error files after a conversion !
Some problems may have occurred without been visually highlighted.
 

Example of a report file 

Note that the conversion summary in the report file takes assemblies into account.


Legend

  • OK = Transferred
  • KO = Not Transferred
  • NS = Unsupported
  • OUT = Out Of Size
    "OUT" entities are OUT of model size. Most of the time, these entities are curves
    and they are out of the V5 model space. These entities are not created.
  • DEG = Degenerated
    • "DEG" entities are degenerated entities. They are solids (MANIFOLD_SOLID_BREP) or
      Shells (OPEN_SHELL), or Curves (LINE, CIRCLE,...).
      Degenerated solids are incomplete solids (at least one Face misses)
  • INV = Invalid
    "INV" entities are Invalid entities, that is to say their description within the STEP file
    is invalid (STEP syntax rules are not respected,...). These entities are not created.

Example of error file:

E:\Report\pm6-hc-214.err

Input FileName : G:\Equipe_STEP\STEP\PDES-Prostep\Tr8\Prod\pm6-hc-214.stp
Output FileName : 


============================================
*** = Processing new independent element
* = Intermediate processing
!! = Independent element K.O.
! = Intermediate error
--------------------------------------------
<I> = Information
<W> = Warning
<E> = Error
--------------------------------------------
[0000] = Message identifier : 0000
[T=xxx] = Entity Type Step : xxx
[#0000] = Entity identifier number : 0000
============================================
Actual display level : Customer
 

Report messages
  Here are some of the messages that may appear:
  • Too many cuts on face boundary.
    Tip : Use topological reduction option (in IGES) or curve optimization (in IGES or STEP) - see User's Guide
    These options are accessible via Tools/Options/Compatibility/STEP dialog boxes, in
    the Continuity optimization of curves and surfaces section.
    Select the Advanced optimization option and push the Parameters... button.
    For more information, click on the link on STEP above.
  • <W> [0904] The face #xx was splitted into nn CATIA V5 faces
    This message indicates that a STEP face has been split into several V5 faces to comply with V5 data structure.
  When the Continuity optimization of curves and surfaces/Advanced optimization option in
Tools/Options/Compatibility/STEP is active, the following warning messages may appear in the report file:
  • The BSpine Surface is not C1: Approximation of the surface is impossible!
    This is just a warning, the surface is imported but is not approximated.
  • The deformation found of the surface approximation (which is calculated by isoparameters) is : xx millimeters.
    This indicates that the real deformation found is higher than the Deformation value
    you have entered in the Parameters box and that the approximation could not be performed.
    When this occurs for several entities, you will find the following information message at the end of the report file:
  • For a better approximation of BSpline surfaces, you can use a "Curves and surfaces approximation"
    Deformation value of at least : xx millimeters
    You can enter this value in the Parameters box of the
    Continuity optimization of curves and surfaces/Advanced optimization     option in Tools/Options/Compatibility/STEP.

What About The Elements You Import ?

 

Assemblies

STEP files containing assembly structures can be imported.
STEP assemblies are mapped with the Product Structure. Geometry can be defined:

  • in STEP in the same file, or in STEP in external files (AP214/AP242 external references mechanism).
    The files referenced are STEP files. External references are supported with STEP AP214/AP203 edition2/AP242 only.
  • or in CATIA in external files. The files referenced are CATIA files.
    External references are supported with STEP AP214/AP203 edition2/AP242, but they are not with STEP AP203.
  • or by links to CATPart, model or cgr files via Product_definition_with associated_document entities.
    Assemblies generated by V4 CATASM and referencing to .model files or cgr files are supported.
  • Regarding STEP XML files, one stpx or stpxZ file contains the structure referencing geometric files (external references or nested assembly).
    Geometric files can be *.stp, *.stpZ or .CATPart files.

 
  • The physical structure of an imported assembly can be defined by one or several CATProducts (one for each node) depending of the option selected.
    (See the Assemblies physical structure option about the import STEP files containing sub-assemblies).
  • CATPart files are linked to the CATProducts as instances of Parts.
  • Model files or cgr files are linked as Shapes.
  • In the case of referenced files, those files must be in the same location than the root STEP file, or be accessible via the search order.
  • You can import of STEP assemblies into V5, even without any STEP license. However, in this case, only the structure of the assembly is imported, not the geometry.

The attributes of products are taken into account as follows:
STEP   V5     
PRODUCT.ID   Part Number
PRODUCT.DEFINITION.ID   Definition
PRODUCT.NAME   Nomenclature
PRODUCT.DESCRIPTION   Description 
PRODUCT_DEFINITION_FORMATION_WITH_SPECIFIED_SOURCE.MAKE_OR_BUY   Source
PRODUCT_DEFINITION_FORMATION.ID   Revision

The attributes of instances of products are taken into account as follows:

STEP   V5
NEXT_ASSEMBLY_USAGE_OCCURRENCE.ID   Component/Instance name
NEXT_ASSEMBLY_USAGE_OCCURRENCE.DESCRIPTION   Component/Description

Tessellated and Exact Geometry

The STEP Tessellated or exact geometry is linked to a STEP product.

For each STEP product, a CATProduct is imported.
For a given STEP product, we can find both exact and tessellated geometry linked to it; in this case, these representations are considered as alternatives.

  • The STEP 3D Exact Geometry of a product is imported as a CATPart instantiated under a CATproduct.

  • The STEP 3D Tessellated Geometry of a product is imported as a CATProduct referencing a CGR file.

Transparency is supported by tessellated geometry.

Transparency is supported by exact geometry (solids, shells and faces).
The transparency of a face of a solid can be overloaded and is kept in the STEP file.
However, the transparency of an instance cannot be overloaded.

With AP242 ed1,

  • The STEP 3D tessellated geometry is imported as a CATProduct referencing a CGR file.
  • When the STEP file contains both exact and tessellated geometry, the exact geometry is taken into account by default.
    An option allows to import the tessellated format.

  • When requested, validation properties are taken into account

     

Composites Data

When the option is selected:

  • The full stacking is kept: ply groups, sequences, plies, cores, cut pieces are kept, as well as the contours, orientations and materials, including their material properties.
  • Filament winding is not supported.
  • STEP Composite Assembly Tables containing ply laminates or Composite Assembly constituents are not supported.
 

User Defined Attributes

The User Defined Attributes taken into account are:

  • the Product: Added Properties (defined for a CATProduct or a CATPArt),
  • the user parameters defined at the PartBody level (i.e. associated to the solid it contains).
  • The user parameters defined at surface feature level, contour feature level and point feature level.

For each User Defined Attribute, STEP preserves:

  • the name,
  • the value (the formula is lost),
  • the type of the parameter (string, integer, real, boolean),
  • the measure (when managed by STEP),
  • the unit (when managed by STEP),
  • the association to a CATProduct or a PartBody.

If the STEP file contains a MEASURE_WITH_UNIT item, it is imported as a string.

The mapping is as follows:
Real NUMERIC_MEASURE (AP214) or REAL_REPRESENTATION_ITEM (AP203 ed2/AP242 ed1)
Integer COUNT_MEASURE (AP214) or INTEGER_REPRESENTATION_ITEM (AP203 ed2/AP242 ed1)
String DESCRIPTIVE_REPRESENTATION_ITEM
Boolean String with value TRUE or FALSE and an additional meta-attribute specifying that the string UDA is a Boolean  (AP214)
or BOOLEAN_REPRESENTATION_ITEM (AP203 ed2/AP242 ed1)
Length MEASURE_REPRESENTATION_ITEM with name
Area MEASURE_REPRESENTATION_ITEM with name
Volume MEASURE_REPRESENTATION_ITEM with name
Mass MEASURE_REPRESENTATION_ITEM with name MASS_MEASURE (AP203 ed2/AP242 ed1)
Density MEASURE_REPRESENTATION_ITEM with name POSITIVE_RATIO_MEASURE (AP203 ed2/AP242 ed1)
Surfacic mass MEASURE_REPRESENTATION_ITEM with name POSITIVE_RATIO_MEASURE (AP203 ed2/AP242 ed1)
Time MEASURE_REPRESENTATION_ITEM with name TIME_MEASURE (AP203 ed2/AP242 ed1)
Angle MEASURE_REPRESENTATION_ITEM with name PLANE_ANGLE_MEASURE (AP203 ed2/AP242 ed1)
Energy MEASURE_REPRESENTATION_ITEM with name ENERGY_MEASURE (AP203 ed2/AP242 ed1)
Force MEASURE_REPRESENTATION_ITEM with name FORCE_MEASURE (AP203 ed2/AP242 ed1)
Pressure MEASURE_REPRESENTATION_ITEM with name PRESSURE_MEASURE (AP203 ed2/AP242 ed1)
Temperature MEASURE_REPRESENTATION_ITEM with name THERMODYNAMIC_TEMPERATURE_MEASURE
Power MEASURE_REPRESENTATION_ITEM with name POWER_MEASURE (AP203 ed2/AP242 ed1)
Voltage MEASURE_REPRESENTATION_ITEM with name ELECTRIC_POTENTIAL_MEASURE (AP203 ed2/AP242 ed1)
Electric resistance MEASURE_REPRESENTATION_ITEM with name RESISTANCE_MEASURE (AP203 ed2/AP242 ed1)
Electric intensity MEASURE_REPRESENTATION_ITEM with name ELECTRIC_CURRENT_MEASURE (AP203 ed2/AP242 ed1)
Luminous intensity MEASURE_REPRESENTATION_ITEM with name LUMINOUS_INTENSITY_MEASURE (AP203 ed2/AP242 ed1)
Magnetic flux density MEASURE_REPRESENTATION_ITEM with name MAGNETIC_FLUX_DENSITY_MEASURE (AP203 ed2/AP242 ed1)
Magnetic flux MEASURE_REPRESENTATION_ITEM with name MAGNETIC_FLUX_MEASURE (AP203 ed2/AP242 ed1)
Mole MEASURE_REPRESENTATION_ITEM with name AMOUNT_OF_SUBSTANCE_MEASURE (AP203 ed2/AP242 ed1)

See also Validation Properties for User Defined Attributes.

In addition to the License Requirements for STEP, the following limitations apply:

  • The following User Defined Attributes are not managed by STEP:
    • constant: value not modifiable is selected.
    • hidden: visibility in the specification tree.
    • comment.

Groups

  • For each APPLIED_GROUP_ASSIGNMENT pointing to a group and a list of entities in the STEP file,
    a Selection Set is created.  This Selection Set is named with the name of the pointed GROUP entity
    and includes all pointed entities.
  • The transfer of groups can be activated/de-activated via the Groups (Selection Sets) option.

Layers

The number of the layer imported is defined by STEP PRESENTATION_LAYER_ASSIGMENT.ID. This is a string representing an integer. If this integer is higher than 1000, the number of layer will be imported as 0.

Annotations

See About 3D Annotations in Graphic Mode and About 3D Annotations in Authorable and Graphic Mode.

Axis System

Axis systems described as supplemental geometry in the STEP file are imported in V5 as standard axis systems with coordinates as parameters.
Axis systems are supported by STEP AP214/AP203 edition2/AP242

The STEP name of the axis system is used for defining the name of the axis system in the specification tree.

The visibility of the axis system is taken into account like for the other geometrical elements (according to the Show option).

The summary in the report file takes the exchange of Axis System  into account.
   
 

Infinite Planes

Infinite planes described as supplemental geometry in the STEP file are imported in V5.
Infinite planes are supported by STEP AP214/AP203 edition2/AP242.

The STEP name of the plane is used for defining the name of the plane in the specification tree.

The visibility of the plane is taken into account like for the other geometrical elements (according to the Show option).

Note: When importing a STEP file, three default planes are created automatically in the NoShow in the CATPart.

STEP Part 42 Entities Imported into V5R6 and Higher 

 

I=Implemented NI=Not yet implemented N/A=Not applicable according to the standard

       

Shape Representation

geometrically
bounded
wireframe

geometrically
bounded
surface

edge-based
wireframe

shell-based
wireframe

manifold
surface

faceted
brep

advanced
brep

High Level Entities

geometric_curve_set

geometric_set

edge_based_
wireframe_model

shell_based_
wireframe_model

shell_based_
surface_model

faceted_brep
brep_with_voids

manifold_solid_brep
brep_with_voids

                              Entity

Point

cartesian_point

I

 I I I I NI I

point_on_curve

 NI NI

N/A

N/A

 NI

N/A

N/A

point_on_surface

N/A

N/A

N/A

N/A

 NI

N/A

 NI

point_replica

 NI NI NI NI

N/A

N/A

 NI

degenerate_pcurve

N/A

N/A

N/A

N/A

 NI

N/A

 NI
 

Curve

line

 I I I I I

N/A

 I

circle

 I I I I I

N/A

 I

ellipse

 I I I I I

N/A

 I

hyperbola

 I I I I I

N/A

 I

parabola

 I I I I I

N/A

 I

polyline

 I I I I I

N/A

 I

b_spline_curve (+ rational)
b_spline_curve_with_knots

 I I I I I

N/A

 I

uniform_curve (+rational)

 NI NI NI NI NI

N/A

 NI

quasi_uniform_curve (+rational)

 I I I I I

N/A

 I

bezier_curve

 I I I I I

N/A

 I

trimmed_curve

 I I

N/A

N/A

N/A

N/A

N/A

composite_curve

 I I

N/A

N/A

N/A

N/A

N/A

composite_curve_on_surface

N/A

 NI

N/A

N/A

N/A

N/A

N/A

boundary_curve
outer_boundary_curve

N/A

 NI

N/A

N/A

N/A

N/A

N/A

pcurve

 NI

N/A

N/A

N/A

 NI

N/A

 NI

surface_curve

 I

N/A

N/A

N/A

  

N/A

  

offset_curve_3D

 NI

N/A

 NI NI NI

N/A

 NI

curve_replica

 NI

N/A

 NI NI NI

N/A

 NI
 

Surface

plane

N/A

 I

N/A

N/A

 I NI I

cylindrical_surface

N/A

 I

N/A

N/A

 I

N/A

 I

conical_surface

N/A

 I

N/A

N/A

 I

N/A

 I

spherical_surface

N/A

 I

N/A

N/A

 I

N/A

 I

toroidal_surface

N/A

 I

N/A

N/A

 I

N/A

 I

degenerate_toroidal_surface

N/A

 I

N/A

N/A

 I

N/A

 I

surface_of_linear_extrusion

N/A

 I

N/A

N/A

 I

N/A

 I

surface_of_revolution

N/A

 I

N/A

N/A

 I

N/A

 I

b_spline_surface
b_spline_surface_with_knots

N/A

 I

N/A

N/A

 I

N/A

 I

uniform_surface

N/A

 NI

N/A

N/A

 NI

N/A

 NI

quasi_uniform_surface

N/A

 I

N/A

N/A

 I

N/A

 I

bezier_surface

N/A

 I

N/A

N/A

 I

N/A

 I

rectangular_trimmed_surface

N/A

 I

N/A

N/A

N/A

N/A

N/A

curve_bounded_surface

N/A

 I

N/A

N/A

N/A

N/A

N/A

rectangular_composite_surface

N/A

 NI

N/A

N/A

N/A

N/A

N/A

offset_surface

N/A

 I

N/A

N/A

 I

N/A

N/A

surface_replica

N/A

 NI

N/A

N/A

 NI

N/A

N/A

Topology

vertex_point

N/A

N/A

 I I I

N/A

 I

edge_curve

N/A

N/A

 I I I

N/A

 I

oriented_edge

N/A

N/A

N/A

 I I

N/A

 I

vertex_loop

N/A

N/A

N/A

 NI NI

N/A

 NI

poly_loop

N/A

N/A

N/A

 NI

N/A

 NI

N/A

edge_loop

N/A

N/A

N/A

 I I

N/A

 I

face_bound
face_outer_bound

N/A

N/A

N/A

N/A

 I NI I

face_surface

N/A

N/A

N/A

N/A

 I I

N/A

advanced_face

N/A

N/A

N/A

N/A

 I NI I

oriented_face

N/A

N/A

N/A

N/A

 NI

N/A

N/A

vertex_shell

N/A

N/A

N/A

 NI

N/A

N/A

N/A

wire_shell

N/A

N/A

N/A

 NI

N/A

N/A

N/A

connected_edge_set

N/A

N/A

I

N/A

N/A

N/A

N/A

open_shell

N/A

N/A

N/A

N/A

 I

N/A

N/A

oriented_open_shell

N/A

N/A

N/A

N/A

N/A

N/A

N/A

closed_shell

N/A

N/A

N/A

N/A

I

 NI I

oriented_closed_shell

N/A

N/A

N/A

N/A

N/A

 NI I
manifold_solid_brep N/A N/A N/A N/A N/A N/A I
brep_with_voids N/A N/A N/A N/A N/A N/A I
faceted_brep N/A N/A N/A N/A N/A

I

N/A