Ioquake3: Where do I get started? (dev)

So, I have been wanting to make a game using open source game engines and such, but I have also really needed extra features.

I have consistently always used quakespasm for all my experiments so far, which is obviously not a very powerful or flexible choice. The only reason I use it is because I have quake 1 and quakeworld modding experience, which has let me make games from scratch using those engines.

I really need some more options regarding world objects, mapping flexibility, rotating level objects, graphics, and all sorts of things.

Essentially, where can I get started making a game from scratch in ioquake3?

I would start by looking at the source for Tremulous, and then replacing everything you don’t want with something you do.