for 3D CAD models I put many of mine at
site is not for source code or gcode but the more common CAD formats. I usually upload STEP files as they are industry standard common format that does not change over the years. although their is talk of a new STEP file format that includes CAM as well as CAD information.
2D cad files are usually DXF files
3dcontentcentral is for designers designing a machine who want a part or small assembly CAD files to add to their design. For example adding a bearing to a model of a machine. I added a 3D model of a lathe, mill, saw, surface grinder for showing machining fixture / vise setups for creating a Setup and Order of Operating sheet for making parts in a machine shop.