for ef2 how do you make triggerable doors and cut sections of wall in half and how to make sounds activate by a button.
Ok, I'll give this one a shot. I don't map for EF2 (yet), but most Q3 engine based games have similar entity keys, so here it goes:
Triggerable doors: Create a brush with the trigger texture and make it a trigger_multiple. This brush will be the area where someone would have to walk through to activate the trigger. While selecting the trigger_mutliple, hit the 'e' key to bring up the entity window. Inside the window type the following information- Key: target Value: door1
Now, go to your door. Once it's selected, it should show up in your entity window. Now type this information- Key: targetname Value: door1
In the 2d and 3d view, you should see a line connecting the door with the trigger. That means that the trigger will activate the door when it's touched.
Cutting brushes in half: Press 'x' to activate the clipper tool. Now place only 2 points on 2 sides of the brush. You should see part of the brush have a yellow outline, and the other part will look normal. Once you've placed your 2 points, hit SHIFT+ENTER and your brush will split in 2.
Triggering a sound: Create a target speaker entity. Use the entity window ('e' key) and type in- key: noise value: path to sound file and also put in- key: targetname value: speaker1
Then create a trigger_multiple like the one you made for the door and type in- key: target value: speaker1
Hope all of that works for EF2 and UberRadiant, and good luck w/ the map.