When did Apple add support for 3D models in Quick Look and Preview?
Quicklook 3d file preview was available since Mac OS 10.5 Leopard as far as I can remember. Common 3D files like OBJ and Collada DAE works out of box for quicklook and preview, Finder too will generate a nice icon for them. Pretty neat!
I presume it was introduced with the availability of the new Metal framework and MetalKit, ModelIO, in macOS El Capitan 10.11. It also added support for other 3D file formats like .stl or .ply. In macOS Sierra 10.12 they added .usd file support. The current formats supported are listed here: MDLAsset class description