Is there a way to find the relationship between screen coordinates and world coordinates without doing complex time-consuming trig? And if “selection” isn’t this, what is it?

Simply, you click and you select an object.

I mean how do you do it in code…

Look here

Heh, do you have anything a little more idiot-friendly? There are topics in there that I don’t think I’ve learned about yet. Should I just forget about it then?

Try - they have a picking tutorial… not sure of the tut number. Also, under Object Selection

[This message has been edited by shinpaughp (edited 05-25-2003).]

If you just want to transform screen coordinates to world coordinates and vise versa, you should look into gluProject and gluUnproject.