With Cineware, native Cinema 4D scenes can be imported directly as assets within Unity. In order for this to work seamlessly, you should save your Project in Cinema 4D via the Save Project for Cineware ... option. This will convert, among other things, the special Cinema 4D Geometry Generator objects for exporting directly to simple Polygon objects. You should also make sure that parametric animations or those created via Nodes are baked in keyframes prior to export so these can also be taken over. Furthermore, you should check how the materials were set up that should adhere to the metalness concept. You can find information about this here. Additional settings for the export can be found within the Project Preferences in the Cineware tab. There you can, for example, define the resolution used for baking textures as well as the bit depth and save format.