Quake2 engine for Papervision3D
For the code to run you need the PAK files included with Quake 2.
I'm not sure yet what licensing applies to Quake2. So for now you need to get the PAK's yourself and extract the BSP map files from them using freely available PAK extractors.
Also see the Quake 1 library.
These details are provided for information only. No information here is legal advice and should not be used as such.