# Convert CAD Models

To use your model in ApertusVR you need to convert you **parametric CAD model into a polygon** mesh file or to one of the supported file formats (see below).  To make this conversion you can use FreeCad software. FreeCAD is an open-source parametric 3D modeler made primarily to design real-life objects of any size. You can download it here: [https://www.freecadweb.org/downloads.php](https://www.freecadweb.org/downloads.php).

After you have installed FreeCad you can import your model by clicking File ->Open and then choose your file from the directories or use File->Import. Click on "Export" in the File menu to export your model to another format. You can find the supported export and import formats here: [https://www.freecadweb.org/wiki/Import\_Export](https://www.freecadweb.org/wiki/Import_Export) .

AprtusVR uses [Open Asset Import Library (assimp)](https://github.com/assimp/assimp) to import files. You can read about the supported file formats here: [https://github.com/assimp/assimp](https://github.com/assimp/assimp) . &#x20;

With this method you can convert for example an unsupported .FCSTD file to a supported .OBJ file.

