How to Jump Over a Building In 3 Easy Steps
Ever wanted to make a level where players could float about freely, without having to worry about that 10,000 foot drop below them? If you have, then you need only pay attention and zero gravity (or as close as you can get to it) is only a few minutes away.
What You Need: A copy of WorldCraft, two rooms, one shall be 128x128x128 (the player spawn room) and one will be 512x512x512. Walls should be 16 units thick, but can be whatever you want. Connect the two rooms at the very top, so that the two ceilings line up. Make a door big enough to fit the player through connecting the two rooms. (The smaller room has to be on the outside of the larger one). Texture the rooms however you want.
Step 1: Create two brushes, the exact width and height of the doorways that are 8 units thick. Texture them as an AAAtrigger Put them both back to back inside of your doorway so that it looks like this...

Step 2: Assign both brushes to trigger_gravity. Make the trigger that is CLOSEST TO THE SPAWN ROOM have it's angle pointed at the spawn room. Set its gravity to 1. Make the trigger CLOSEST TO THE HUGE ROOM angled towards the huge room. Set its gravity to 0.1 Throw in a player start in the respawn room and you're all set.
*note: You can't set gravity to 0, if you do you will get a big surprise when walking out of the spawn room.
Step 3: Compile your map with lights and boundaries included. If you want even more fun, put in blocks of different heights to jump on and over. If you want to cheat, you can use the example map included to compile and play.
Additional Notes
Be sure to keep R_speeds in your map VERY low. A high ping DM level with low gravity can make it extremely hard to maneuver in.