Is there a way to edit an existing map?

You have unpak it, then reverse the bsp to a map.

Lookup q3radiant map editor

Do the map making tools do this conversion?

There's a much easier solution to edit entities (items) than decompiling maps.

I had a small, unreleased ioquake3 source port I made some years ago. Assuming you're on Windows, it will let you dump and then load entity (.ent) files directly from maps in-game. All you need to do is:

1. set sv\_entlist\_dump 2 and sv\_entlist\_load 1
2. load up/map\_restart a map to create an ent file in your base game's maps folder
3. edit the created .ent file in a text editor, changing the entities/items as you like (you'll need to know entity names for items in order to do this)
4. reload/map\_restart the map again to see the immediate changes

The source port also features bloom (from Wolfcam), hor+ aspect correction for FOV and HUD (r\_arc\_\* cvars), hacky fixes for various mods, QL bsp and legacy encrypted pk3 support (if I remember correctly) and probably a bunch of other things I completely forgot about.

Here ya go: https://www.dropbox.com/s/4t0l1ttub62nlqk/ioq3pp.zip?dl=0

This is very, very kind and I REALLY appreciate it!

I want to ask though - can you also include the source code?

My bad, here it is: https://github.com/themuffinator/ioq3-pp

Thanks! This is your fork of ioq3?

Yes

I don't remember. Just Google bsp to map

Did it work for you?

I haven’t had a chance to get started with it yet unfortunately. It might be awhile given my schedule, etc.