Convert CGR to STP

Manufacturing, inspection, or downstream CAD software may require a STEP file when the supplier provides only a CATIA visualization file. The conversion is also used to exchange geometry with systems that cannot read CATIA's native formats, but a CGR-only conversion may not retain usable exact geometry.

What the CGR format is

CGR means CATIA Graphical Representation. CATIA V5 uses it as lightweight tessellated display data for cached assembly components, digital mock-up review, supplier viewing, and navigation of large assemblies.

A CGR normally contains polygonal visualization geometry, not the CATIA feature tree, sketches, constraints, parametric dimensions, exact analytic surfaces, or editable solid definition. It can appear in CATIA cache data, assembly packages, and files intended for viewing rather than manufacturing.

What the STP format is

STP, also written as .step, is the ISO 10303 STEP neutral CAD format. CATIA, Siemens NX, Creo, SOLIDWORKS, Fusion, FreeCAD, CNC systems, and inspection software commonly use STEP for geometry exchange.

STEP can store precise boundary-representation solids and surfaces, assembly placement, and some product metadata. AP203 and AP214 are common protocols; AP242 is a newer choice when the receiving system supports it. STEP does not preserve CATIA's feature history, sketches, constraints, or design intent, so imported data is generally a non-native solid or surface model.

Preferred conversion method

Use the original CATIA model instead of converting its display cache whenever possible.

1. Request the source .CATPart files and, for an assembly, the .CATProduct and all referenced components.
2. Open the part or assembly in CATIA V5 and confirm that the required components are loaded from their source files, not represented only by CGR cache data.
3. Use the STEP export command provided by the installed CATIA workbench. In versions that expose it through the file menu, use File → Save As and select STEP.
4. Choose AP242 or AP214 if the receiving system supports it; use AP203 for a legacy recipient. Export the complete assembly or individual parts according to the recipient's import requirements.
5. Open the resulting .stp in the target system and check units, bounding dimensions, component placement, solid validity, and missing references.

This route exports the source model's exact surfaces and solids, although it still does not transfer CATIA parametric history.

Converting when CGR is the only file

Use a commercial translator that explicitly lists CGR input and STEP output. Datakit CrossManager is a relevant desktop option for CATIA and neutral-format translation; verify CGR support in the current edition before purchasing or processing a project. The exact interface varies, but the workflow is to import the CGR, select STEP output, choose a supported AP protocol and unit system, then export the file.

Some translators interpret CGR as a polygonal mesh and produce a faceted STEP shell or faceted B-rep. That output is not equivalent to the original CATIA solid: it may be unsuitable for machining, precise mating, mass properties, or dimensional editing. CAD repair or reverse-engineering software may be required to stitch surfaces and reconstruct planes, cylinders, holes, and other analytic faces.

General online converters are usually unsuitable for CGR because many do not accept the format, preserve assembly structure, or produce exact solids. Use an online service only if its current format list explicitly confirms CGR input and STEP output, and only after checking file-size limits, assembly handling, retention policy, and confidentiality requirements. Do not upload proprietary design data without authorization.

Quality and compatibility limits

• Accuracy: CGR tessellation quality is set when the representation is generated. A converter cannot restore geometric precision that was discarded before the CGR was created.
• Editability: CGR-to-STEP conversion does not recover CATIA features, parameters, sketches, constraints, or design intent.
• Assemblies: A CGR package may omit component names, hierarchy, metadata, or external references. Confirm that the translator preserves placement and required component separation.
• Units: STEP can contain unit information, but importers may apply document defaults incorrectly. Verify a known dimension after import.
• Manufacturing use: Compare bounding dimensions and critical interfaces with the source, then run the receiving CAD system's geometry-validation or healing check before using the result for production.