# Free CAD Sample Files: STEP, IGES, STL & More

Download known-good CAD sample files for geometry, units, assemblies and viewer testing.

## Free CAD files for viewer and converter testing

These files are public demonstration models, not customer data. Use them to test a CAD viewer, verify units, exercise a geometry-property pipeline or compare results between applications.

| Sample | What it tests | Expected result / note |
| --- | --- | --- |
| [block.step](https://www.cadprops.com/samples/block.step) | Basic closed STEP solid | 40 × 30 × 20 mm; 24,000 mm³ volume; 5,200 mm² area |
| [cylinder.step](https://www.cadprops.com/samples/cylinder.step) | Analytic curved STEP geometry | Radius 10 mm; height 30 mm; volume 3,000π mm³ |
| [inch-block.step](https://www.cadprops.com/samples/inch-block.step) | STEP unit normalization | Declares inches; normalizes to 25.4 × 50.8 × 76.2 mm |
| [open-surface.step](https://www.cadprops.com/samples/open-surface.step) | Open-surface error handling | 20 × 30 mm face; 600 mm² area; no solid volume |
| [assembly.step](https://www.cadprops.com/samples/assembly.step) | STEP instances / assembly totals | Two 10 × 20 × 30 mm block occurrences; total 12,000 mm³ |
| [bearing-housing.step](https://www.cadprops.com/samples/bearing-housing.step) | Curved faces, bore and mounting holes | Original CADProps demonstration housing; properties calculated at runtime |
| [bearing-housing-rev-b.step](https://www.cadprops.com/samples/bearing-housing-rev-b.step) | CADProps original housing revision | One mounting hole enlarged; same source coordinates for comparison |
| [box.iges](https://www.cadprops.com/samples/box.iges) | IGES input | Small known geometry for IGES reader tests |
| [box.stl](https://www.cadprops.com/samples/box.stl) | STL mesh input | Mesh dimensions/properties; physical units must be handled explicitly |
| [box.obj](https://www.cadprops.com/samples/box.obj) | OBJ mesh input | Small mesh for viewer/conversion tests |
| [box.3mf](https://www.cadprops.com/samples/box.3mf) | 3MF input | Small core-geometry package |
| [box.glb](https://www.cadprops.com/samples/box.glb) | Static GLB input | Small static mesh model |
| [fixture-plate.dxf](https://www.cadprops.com/samples/fixture-plate.dxf) | DXF drawing with layers, dimensions, hatching and an A4 layout | CADProps original drawing of the 100 × 70 × 16 mm CNC demo plate; dimensions and hatch use the full drawing preview |
| [fixture-plate.plt](https://www.cadprops.com/samples/fixture-plate.plt) | HP-GL/2 plot file | The same sheet as a pen plot; units reported as unknown |

## Why known-good samples matter

When a customer file fails, first test the same workflow with a known-good model.

If the sample succeeds and the customer file fails, investigate file version, geometry, dependencies or data quality. If both fail, investigate the reader, deployment or processing pipeline first.

## Reproducible STEP property cases

The STEP samples are generated from analytical geometry. Expected values are documented so you can compare independent readers without guessing what the answer should be.

- [Inch unit check](https://www.cadprops.com/guides/step-inch-unit-check/index.md)
- [Open-surface volume check](https://www.cadprops.com/guides/step-open-surface-volume-case/index.md)
- [Assembly instance properties](https://www.cadprops.com/guides/step-assembly-instance-properties-case/index.md)

The sample API and the upload workflow use the normal processing path; CADProps does not inject precomputed property values into the result.

## Licenses

The CADProps-generated samples below are dedicated to the public domain under [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/): use, modify and redistribute them for any purpose without asking or giving credit. Their geometry is produced by scripts in the CADProps repository, so the expected properties stay reproducible.

- `block.step`, `cylinder.step`, `inch-block.step`, `open-surface.step`, `assembly.step`
- `bearing-housing.step`, `bearing-housing-rev-b.step`

`flange-bearing.step` is not CC0. It is the KFL08 flange bearing by hasecilu from the [FreeCAD Parts Library](https://github.com/FreeCAD/FreeCAD-library), licensed under [CC BY 3.0](https://creativecommons.org/licenses/by/3.0/). Keep the attribution when you share it.

## More free parts: the CADProps parts library

For more realistic shapes, the [CADProps parts library on GitHub](https://github.com/cadprobs-a11y/cadprops-step-models) has 30 parts: fasteners, washers and sleeves, brackets, bearings and transmission parts, and flanges and pipe fittings. Each part comes as STEP, STL and IGES, with a preview, its X × Y × Z envelope in millimetres and a source record. 23 are community models under CC BY 3.0 that keep their author credits, and 7 are CADProps originals under CC0. Downloading them does not need a CADProps account.

| Part | Envelope listed in the library (mm) | Useful for checking |
| --- | --- | --- |
| Socket-head screw M5 × 16 | 8.50 × 8.50 × 21.00 | Cylindrical edge diameters and overall length |
| 608ZZ ball bearing | 22.00 × 22.00 × 7.00 | Bore and outer diameters |
| 2020 corner bracket | 17.00 × 21.00 × 21.00 | Hole positions on a right-angle part |
| DN15 stamped flange | 95.00 × 11.50 × 95.00 | Overall size and thickness of a flat flange |

Open the STEP version in the viewer and compare the overall dimensions with the listed envelope. The two describe the same axis-aligned box. If they differ, check the source units first.

## Use the interactive viewer

The workspace on this page uses the same processing pipeline as uploaded files. You can also download a sample above and test it in another CAD application or service.

For current support boundaries, see the [CAD format compatibility matrix](https://www.cadprops.com/supported-formats/index.md).

For fast part and assembly viewing, see [Fast CAD viewing with CADProps](https://www.cadprops.com/fast-cad-viewer/index.md), with real model examples and loading times.

HTML page: https://www.cadprops.com/examples/