STEP:Export

• CATProduct documents (resulting in STEP AP203/AP214/AP242 files in compliance with Part 44)
  
• CATShape documents. However, if you re-import a STEP file made from a CATShape, you will create a CATPart.

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

You can find further information in the Advanced Tasks:

• Trouble Shooting,
• Best Practices,
• FAQ,
• VBScript Macros.
• and in the Customizing STEP Settings chapter.

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

The table in What about the elements you export ? provides information on the entities you can export.

1. Go to the Tools > Options > Compatibility > STEP tab.
   Under Application Protocol (AP), select the required Application Protocol from the list, and click OK.

2. Open the CATPart or CATProduct document to be saved in STEP.

3. When the document is open, select the File > Save As... command.

4. Specify the name you want to give to the STEP file in the File name:  field.

5. Select STEP (*.stp), STEP (*.stpZ), STEP (*.stpx) or STEP (*.stpxZ) from the Save as typelist type.
   Z stands for compressed files, x for STEP XML files.

6. Click the Save button to confirm the operation.
   For a CATProduct, there is one conversion operation for each CATPart document referenced by the product.

   A progress bar is displayed for each conversion operation.

   You can use the Cancel button to interrupt the transfer at any time. The current conversion operation is then interrupted (after the processing of the current independent entity) and the partial conversion already performed is saved in the STEP file.

7. Open the .stp file you will see that the file header contains the following information:

   the file name the date of creation (with the year expressed in four digits meaning that your STEP data will be year 2000-compliant) the V5 version used for the conversion. Note that the file description field is not written in the header of STEP XML files.

• Detailed report (not yet completely available for export),
• Validation Properties,
• Groups (Selection Sets),
• 3D annotations,
• Composites,
• User Defined Attributes,
• Application Protocol (AP),
• Exact geometry as, to export data as exact or tessellated,
• Units, to choose the unit of the exported file,
• Show/NoShow, to export all entities or only visible entities,
• Header of the STEP file,
• Assemblies, to use external references, thus reducing memory problems.

After exporting data to 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 on Windows is 

•  
• and  $HOME/CATReport on UNIX.

You can find statistics about the quality of the transfer in those files.

Example of report file:

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

Example of error file:

C:\\WINNT\\Profiles\\vmu\\Local Settings\\Application Data\\DassaultSystemes\\CATReport\03_ClosedTopology.err

Input FileName : E:\\users\\WebInterfaces\\ItfEnglish\\itfug.doc\\src\\samples\03_ClosedTopology.CATPart
Output FileName : E:\\users\\WebInterfaces\\ItfEnglish\\itfug.doc\\src\\samples\03_ClosedTopology.stp


============================================
*** = 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

Exchanging 3D Geometry

One of the current primary uses of the AP214/AP242 Standard is to exchange geometry. The STEP Interface enables users to exchange the B-REP of exact solids. The exchange process is based on AP214/AP242. This application protocol is very similar to AP203 as it shares the same resources expressed in the PART 42.

Please remember:

• You can export the bodies (volumes, shells and faces) of CATPart or CATShape documents (resulting in STEP AP203/AP214/AP242 files in compliance with Part 42).
• The export of Shells occurs with no limitation and all the structure information can be recovered. 
• When a CATProduct document is exported the geometry/topology of the CATPart or CATShape or .model documents is also stored in the .stp file.
• 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.

Exchanging Visual Presentation of 3D Geometry (Exact or Tessellated)

The STEP interface enables users to exchange visual presentation of exchanged geometric elements.

Please remember:

• Layers:
  • Layers on exported entities are supported. 
    However, since V5 does not support layers on tessellated geometry, export of layers on tessellated geometry is not possible.
  • The visibility of layers is not taken into account: all layers are handled in the same way, event if filters are defined.
  • The V5 number of layer is mapped with STEP attribute PRESENTATION_LAYER_ASSIGNMENT.ID

• Color:
  • Colors are not exported with AP203 edition1.
  • When the color of a given face is different from the color of its solid, an entity OVER_RIDING_STYLE_ITEM is created in the STEP file, and the face keeps the overriding color.
  • STEP limitation with assemblies: since attributes can not be set on instances of components, the color of instances are not taken into account. 

• Lines:
  • V5 handles 7 types of line whereas STEP proposes 5 types only. The mapping is the following:

    V5 line type	STEP line type
    	Continuous
    	Dotted
    	Dashed
    	Chain
    	Chain double dash
    	Dotted
    	Chain

• Thickness is supported at export.

• Points:
  • Point styles are mapped as follows:

    STEP point style	V5 point style
    cross, triangle
    plus
    circle
    square
    asterisk
    dot

• Points belonging to a sketch:
  A point belonging to a sketch is exported only if the sketch contains only points.

Tessellated and Exact Geometry

V5 data are can be exported to STEP tessellated geometry as follows:

• Solid geometry is exported to a STEP file as TESSELLATED_SOLID, and TESSELLATED_EDGE for the edges.
• Surfacic geometry is exported as TESSELLATED_SHELL, and TESSELLATED_EDGE for the edges.
• Wireframe geometry is exported as TESSELLATED_WIRE or TESSELLATED_VERTEX.
• Structured tessellations are supported. For example, a structured cgr representing a keyboard is exported to a STEP file as a structured STEP tessellation (the geometry of all the keys of a given type is represented as a single solid).
• By default, exact geometry is exported as B-rep exact geometry.
  With AP242 ed1, you can also export exact geometry as tessellated geometry.
• When the geometry is exported to STEP (all Assemblies options) the visualization representation referenced by a product are exported as STEP Tessellated Geometry.
• Validation properties are suported when requested.
• 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 (It is ignored at export).

See Exact geometry as for more information.

Composites Data

When the option is selected:

• Only the engineering stacking is taken into account.
• Preliminary design data are not supported.
• Only materials used by the engineering stack are supported.
• Flat pattern is not supported.
• Analysis and simulation 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.

The mapping is as follows:

See also ee also Validation Properties for User Defined Attributes.

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

• Sets of user parameters are not supported. The sets and the parameters they contain are ignored at export.
• User parameters associated to a feature of a solid are not exported (only user parameters defined at the PartBody level are exported).
• The following User Defined Attributes are not managed by STEP:
  • constant: value not modifiable is selected.
  • hidden: visibility in the specification tree.
  • comment.
• AP242 XML files do not support UDA attached to a product, but they support UDA attached to a geometrical entity.
• In the current release, User Defined Attributes at product level are taken into account for assemblies only if One STEP file is selected.

Miscellaneous

Please remember:

• Axis systems:
  They are supported by AP214, AP214 edition3, AP203 edition2 and AP 242.
  When exporting a CATPart, the Axis System is exported in STEP as supplemental geometry according to the Recommended Practices published by ProSTEP.
  When exporting a CATProduct referencing a CATPart, the Axis System of the CATPart is also exported in STEP as supplemental geometry.
  The name of the Axis System in the specification tree is exported as the name of the Axis System in STEP (i.e. AXIS2_PLACEMENT_3D.NAME).
  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
  They are supported by AP214, AP214 edition3, AP203 edition2 and AP 242.
  The name of the infinite plane in the specification tree is exported as the name of the infinite plane in STEP (i.e. PLANE.NAME).
  The visibility of the plane is taken into account like for the other geometrical elements (according to the Show option).

• Units:
  The units used are V5 units i.e. MKSA (radians, mm). The angles are exported in radians and lengths in mm or Inch.
  However:
  AP242 XML .stpx or .stpxZ files do not support the export to inch. If you have set the export unit to inch:
  • The unit of the geometry (.step files) is inch.
  • The unit of the assembly (.stpx files) is mm. AVP and instance position transformations are affected.
  • A warning is written in the .err file.

• Wires:
  If a feature contains several wires (result of a section), the wires will be exported as Composite Curves and will all have the same name (that of the feature).

• Show/NoShow:
  By default, hidden objects (i.e. that belong to the No Show space) are not exported. See option Show/NoShow.

• Selection set (AP214, AP214 edition3, AP242  only!):
  For each selection set,an entity APPLIED_GROUP_ASSIGNMENT is created. This entity points to a GROUP entity and to a list of exported geometric entities. The attribute NAME of the entity GROUP is defined by the name of the selection set.
  The transfer of groups can be activated/de-activated via the Groups (Selection Sets) option.
  Note that selection sets are not supported on V5 tessellated geometry.

• When a Body is contained in a Selection Set:
  • a GROUP entity is created in the STEP file for that Selection Set,
  • all the entities of the Body exported in STEP are put into that GROUP.
• When an exported entity is contained in a Selection Set:
  • a GROUP entity is created in the STEP file for that Selection Set,
  • the entity is put into that GROUP.
• A solid resulting from a PartBody is exported in a group if and only if the PartBody is in the Selection Set corresponding to the group.
  If a feature of a PartBody is in a Selection Set, it is not taken into account during export.

Annotations

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

Assemblies

Support of External References to STEP or V5 files on Export: the External References functionality is available only with AP214, AP214 edition3, AP203 edition2, AP242. For more information about the Customizing export mode, refer to Customizing STEP Settings. 

• Multiple Instances of a Part in an Assembly is possible: a link with the same reference is established in order to limit the number of instances.
• STEP limitation with assemblies: since attributes can not be set on instances of components, the color of instances are not taken into account. 

You can save the structure of an assembly with links to CATParts files via  PRODUCT_DEFINITION_WITH_ASSOCIATED_DOCUMENT entities. 

.model files referenced by a CATProduct are exported in STEP with the following settings:

• Application Protocol AP203 + Structure and Geometry in one file
• Application Protocol AP214 (or AP214 edition3, or AP242) + Structure and Geometry in one file
• Application Protocol AP214 (or AP214 edition3, or AP242) + STEP external references
• Application Protocol AP203 edition2 (or AP242) + STEP external references.

The attributes of products

are taken into account as follows:

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

Wire (GSM, Free Style, etc.)

Not generated by V5

 OpenShell (GSM, Shape Design, Free Style, etc.)

Not generated by V5

 Geometrical set

geometrically bounded wireframe

geometrically bounded surface

edge-based wireframe

shell-based wireframe

manifold surface

faceted brep

advanced brep

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

Point

cartesian_point

point_on_curve

N/A

N/A

N/A

point_on_surface

N/A

N/A

N/A

N/A

point_replica

N/A

N/A

N/A

N/A

degenerate_pcurve

N/A

N/A

N/A

N/A

Curve

line

thru edge_curve

N/A

circle

thru edge_curve

N/A

ellipse

thru edge_curve

N/A

hyperbola

thru edge_curve

N/A

parabola

thru edge_curve

N/A

polyline

N/A

b_spline_curve
(+ rational)

b_spline_curve_with_knots

thru edge_curve

N/A

uniform_curve (+rational)

N/A

quasi_uniform_curve 
(+rational)

N/A

bezier_curve

N/A

trimmed_curve

N/A

N/A

N/A

N/A

N/A

composite_curve

N/A

N/A

N/A

N/A

N/A

composite_curve_on_surface

N/A

N/A

N/A

N/A

N/A

boundary_curve

outer_boundary_curve

N/A

N/A

N/A

N/A

N/A

pcurve

N/A

N/A

N/A

surface_curve

N/A

N/A

N/A

N/A

offset_curve_3D

N/A

N/A

curve_replica

N/A

N/A

Surface

plane

N/A

N/A

N/A

cylindrical_surface

N/A

N/A

N/A

conical_surface

N/A

N/A

N/A

N/A

spherical_surface

N/A

N/A

N/A

N/A

toroidal_surface

N/A

N/A

N/A

N/A

degenerate_toroidal_surface

N/A

N/A

N/A

N/A

surface_of_linear_extrusion

N/A

N/A

N/A

N/A

surface_of_revolution

N/A

N/A

N/A

N/A

b_spline_surface

b_spline_surface_with_knots

N/A

N/A

N/A

N/A

uniform_surface

N/A

N/A

N/A

N/A

quasi_uniform_surface

N/A

N/A

N/A

N/A

bezier_surface

N/A

N/A

N/A

N/A

rectangular_trimmed_surface

N/A

N/A

N/A

N/A

N/A

N/A

curve_bounded_surface

N/A

N/A

N/A

N/A

N/A

N/A

rectangular_composite_surface

N/A

N/A

N/A

N/A

N/A

N/A

offset_surface

N/A

N/A

N/A

N/A

N/A

surface_replica

N/A

N/A

N/A

N/A

N/A

Topology

vertex_point

N/A

N/A

thru edge_curve

N/A

edge_curve

N/A

N/A

thru oriented_edge

N/A

oriented_edge

N/A

N/A

N/A

thru edge_loop

N/A

vertex_loop

N/A

N/A

N/A

N/A

poly_loop

N/A

N/A

N/A

N/A

N/A

edge_loop

N/A

N/A

N/A

thru wire_shell

N/A

face_bound

face_outer_bound

N/A

N/A

N/A

N/A

face_surface

N/A

N/A

N/A

N/A

N/A

advanced_face

N/A

N/A

N/A

N/A

oriented_face

N/A

N/A

N/A

N/A

N/A

N/A

vertex_shell

N/A

N/A

N/A

N/A

N/A

N/A

wire_shell

N/A

N/A

N/A

N/A

N/A

N/A

connected_edge_set

N/A

N/A

N/A

N/A

N/A

N/A

open_shell

N/A

N/A

N/A

N/A

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

oriented_closed_shell

N/A

N/A

N/A

N/A

N/A