I am looking into writing AI from scratch for Doom 3 mod (AI scripts), but I am not really sure where to start. I just want to start small, basically just have spawned AI to idle and look at player (turn toward) when player is inside a certain radius around AI.

I am not sure if anyone here ever modded Doom 3, but I figured it worth asking Thanks.

1) Do you know how to get the location of an object in Doom 3?

2) Do you know how to measure distance between objects in Doom 3?

3) Do you know how to change the facing of an object in Doom 3?

If you answered yes to those questions, then you can write the AI you posted on your own. If you do not know how to do those things, this isn't an AI question and is more of a Doom 3 code question.

I know all of those things. Except that there is a special structure to script, etc. Plus if I delve into AI dev, I wouldn't be able to work on art (I do art primarily, and some gameplay scripting; sometimes I poke at C++ code; so do more programming would generally means zero progress on assets :( )

well. scripting for doom3 is very specefic for forum like gamedev and i think its hard to find an answer for that. instead best place for finding you answer is id dev net website :

http://www.iddevnet.com/doom3/script.php

but in general when you want to generalize AI for a character first of all you have to make an state machine for it. states are like IDLE SEARCHING ATTACKING and ... in each of these states AI BOT behave different and in conditions like player is in distance less than certain value go to state attack form idle and... there are alot in internet about that. first of all i think you have to learn about game it concepts and after that start special script like doom3.