3D game engine that works like marathon

[Qweasy908]

I want to talk about making a 3D game engine that works like marathon. The only idea I have is 3D shapes that are independent from one another can occupy the same space and are linked together on the sides only to form a map. Maybe I can do this with separate bsp trees for each 3D shape. I know I need a way to split up a wall so differently sized 3D shapes can link with no problems.

[Pfhorrest]

https://en.m.wikipedia.org/wiki/Portal_rendering

[Qweasy908]

https://en.m.wikipedia.org/wiki/Portal_rendering

Thanks.
I should start with portal rendering then try to find a way to keep marathons 5D space.

[Pfhorrest]

Portal rendering will (or can) give you 5D space right off the bat. Marathon's 5D space is a consequence of its portal rendering method.