What is cadimporter?

CAD Importer is a Unity package that lets you bring CAD and BIM model files, including STL, PLY, OBJ, glTF, GLB, STEP, IGES, and IFC formats, straight into a Unity project. It is aimed at people building robotics simulations and digital twins, where accurate, ready to use 3D models matter more than pretty renders. When you import a file, the package automatically converts it to meters with the correct up axis, keeps the assembly's hierarchy and pivot points intact, welds the mesh, smooths normals while keeping sharp edges crisp, generates a level of detail chain for performance, applies physically based materials, and builds simplified colliders for physics. For STEP, IGES, and IFC files specifically, this preserved hierarchy means robot joints or building floors map correctly onto Unity's own simulation objects. IFC imports go further, adding an identity component with the building element's type and properties, plus a tool that recolors the model by category, like glass, steel, or concrete, so you can visually inspect a building model by type. Installation happens through Unity's Package Manager using a git URL, and the package requires Unity 6000.0 or newer. Importing STEP, IGES, or IFC files also needs a free local install of FreeCAD, which the package detects automatically. Everything else, including STL, PLY, and glTF files, works without any extra software. There is also a runtime API for loading CAD files while a simulation is actually running, written to avoid pausing or stuttering the app, which matters for live digital twin scenarios. The package is written entirely in C# with no native plugins, and ships with a demo scene plus a batch import window for converting many files at once. The project is MIT licensed, meaning it can be used freely, including in commercial projects, as long as the copyright notice is kept.