# CATPart to STEP Converter Online: CATIA V5 Parts
Convert CATIA V5 CATPart files to STEP online. Exact STEP needs a complete B-Rep; otherwise you get a mesh STEP. CATProduct is not converted.
Convert a CATIA V5 CATPart to STEP. CADProps reads the part in-house: when its B-Rep is reconstructed completely and matches the display geometry CATIA saved, you can download an exact STEP; otherwise the export is a mesh STEP built from the saved display triangles. View and measure without an account; sign in to convert.
## What the STEP export contains
Exact STEP keeps surfaces and edges, so CAD and CAM applications can use it as solid geometry. Mesh STEP stores display triangles in a STEP file: suitable for visual review and overall size, not for machining features or surface edits. The Convert dialog offers exact STEP only when it is available for the uploaded file; STL, OBJ and GLB come from the same preview.
## When you get exact STEP
CADProps rebuilds the CATPart B-Rep and compares it with the display geometry CATIA saved. If every face is rebuilt and the two agree, exact STEP is offered. If not, only mesh STEP, STL, OBJ and GLB are offered. Parts saved without display geometry show only their thumbnail and cannot be converted.
## CATProduct assemblies are not converted
A CATProduct references its parts instead of holding their geometry. CADProps shows only the thumbnail saved in a CATProduct and does not assemble or convert it. Export STEP from CATIA for the whole assembly, or upload the CATPart files one at a time to view and convert each part.
## STEP does not carry CATIA history
The neutral file does not recreate CATIA sketches, constraints, parameters or the feature tree as editable data. Keep the CATPart and its revision as the editable source.
## Check the converted model
Verify one known dimension, the expected bodies and critical curved or machined features. Reopen the STEP in the receiving CAD/CAM application where practical.
## Check version support when a file will not open
Support covers CATIA V5 CATPart files whose saved data can be read; compatibility with every release is not established. CATShape, CGR, 3DXML and CATIA V4 MODEL/SESSION are not inputs. Record the saving release when asking the sender for a fresh export.
## Plan the upload and account step
Use the upload limit shown in the workspace and only upload files you are authorized to share with CADProps. Processing runs on the server. Your files stay private, and temporary files are deleted together with their previews and results when they expire; the privacy policy has the details. Sign in before starting conversion.
**Input formats:** CATPart
**Points:** viewing and measuring are free. A new account gets 3 free conversion points; free points are valid for 90 days. One point converts one file to every output format for 30 days, and a failed or incomplete conversion uses none. See [pricing](https://www.cadprops.com/pricing/).
[Open this tool](https://www.cadprops.com/workspace/index.md)
General steps for uploading, viewing, sectioning, measuring, converting and exporting are explained once in [How it works](https://www.cadprops.com/how-it-works/index.md). This page covers what is specific to this file type.
## Real CADProps screenshots
The screenshots show the English interface. Captions and instructions describe the same operations.
Convert CAD files — SS_PL_8x6x0.5_B.CATPart
[Sample source and verification](https://github.com/sheetd/BatchProcess)
Properties — catia-to-step.stp · 203.2 × 152.4 × 12.7 mm · 393,289.536 mm³ · 70,967.6 mm²
## When a result needs another check
Viewing can start without an account. Conversion, account storage and share creation require signing in. Temporary files expire after the displayed retention period. Read the privacy statement for server processing and deletion, and the accuracy notes before using numerical results. Do not assume that hiding a part, clipping it or exploding an assembly changes the exported source geometry.
[When a result needs another check](https://www.cadprops.com/accuracy/index.md) · [Input formats](https://www.cadprops.com/supported-formats/index.md)
## Continue with a related task
- [CATPart Viewer Online: Open CATIA V5 Part Files](https://www.cadprops.com/tools/catia-viewer/index.md)
- [STEP File Viewer Online: Open STP Files, No Account](https://www.cadprops.com/tools/step-viewer/index.md)
- [STEP File Dimensions Online: Measure X, Y, Z & Distances](https://www.cadprops.com/tools/cad-dimensions/index.md)
Supported 3DXML exports with XML or CATIA V5 binary (UVR) `.3DRep` tessellations open in the [3DXML viewer](https://www.cadprops.com/tools/3dxml-viewer/index.md), with package-local product references and placed meshes. Units are unverified and assumed millimetres; other binary representations, textures and exact B-Rep are unsupported. Mesh exports do not provide exact CATIA-to-STEP conversion.
## Capabilities and limits
- Convert CATIA V5 CATPart files to STEP online. Exact STEP needs a complete B-Rep; otherwise you get a mesh STEP. CATProduct is not converted.
- Exact STEP needs a complete B-Rep that matches the saved display; otherwise the export is mesh STEP. CATProduct assemblies are not converted.
- Files are uploaded for server processing; support depends on format, version and geometry.
- Viewing and measuring do not require an account. Free conversion points are valid for 90 days. Sign in to convert, save files across devices or create share links.
## Questions about this task
### Can I convert CATPart to STEP online?
Yes. Upload the CATPart, sign in and choose STEP. You get an exact STEP when the part's B-Rep is read completely; otherwise the Convert dialog offers a mesh STEP built from the saved display triangles.
### Can I convert CATProduct to STEP online?
No. CATProduct assemblies show only their saved thumbnail and are not converted. Export STEP from CATIA, or upload the CATPart files individually.
### What is the difference between exact STEP and mesh STEP?
Exact STEP contains surfaces and edges that CAD and CAM applications can use as solids. Mesh STEP contains triangles: fine for viewing and overall size, not for machining features or surface edits.
### Will STEP preserve CATIA features?
No. STEP is a neutral exchange representation and does not restore the original CATIA parametric design history.
### How do I verify the STEP output?
Check units, one known dimension, the expected bodies and critical geometry in the receiving application.
### Do I need an account to convert files?
View and measure without an account. Register or sign in to convert, save files and create share links. Recipients can view shared models without an account.
### Which CATIA V5 versions can I convert?
The accepted extension does not imply compatibility with every release. If the file cannot be read or shows only a thumbnail, confirm the source release or request a fresh STEP export from CATIA.
### Can I convert CATPart to STP instead of STEP?
STP and STEP are filename extensions for the same exchange format. Use the STEP target, then confirm that the receiving application accepts the exported file. Changing a native file extension alone does not convert its contents.
HTML page: https://www.cadprops.com/tools/catia-to-step/
