Eliminating Map Problems

[Bean]

Hey, mappers, add something to this list. Please, let it pertain to curing BSP holes, Hall of Mirror Problems, and optimizing performance for maps.

I'll start by adding a few:

-Create complex brushes out of many decorative add/sub brushes.
-Make high-node decorations semi-solid.
-Zone Portal correctly

Anyone else have some to add?

[NutWrench]

If you get BSP holes in the vicinity of a complex Add brush, try moving the add brush slightly and rebuilding. This can change the way the editor partitions up the space around the brush and get rid of those BSP holes. The BSP view in the 3D window can help find these holes for you. (You'll need to re-build to update the BSP.) Sometimes, just changing an Add brush to semi-solid can get rid of the BSP hole (more on this below)

You can also position the Add brush so it doesn't actually come into contact with the wall or floor. If you're adding some boxes, make them "float" 1 or 2 units above the floor or away from the wall). If the Add brush doesn't actually touch the floor/wall then it won't cut up the floor/walls BSP. (The player won't be able to tell that the boxes are floating unless he can get close enough to the floor to look underneath.)
This is a good trick to use with decorations like boxes, light fixtures, etc.

You can make the Add brush a semi-solid. Only Add brushes can be made semi-solid. Switch to the wire-frame view and left click on your brush to highlight it. Then right click on it and select "Make semi-solid" from the Solidity sub-menu. The brush will turn pink if you did it correctly. Now switch to the BSP view. Remember that this BSP view was generated the last time you re-built the map so, it won't show the changes you just made(this is why it's so important to re-build after changing your map geometry). Re-Build. You should see a BIG reduction in the number of BSP cuts. Fewer cuts means the map will run faster, so this is a great way to optimize your map for speed.
The only downside to semi-solid brushes is that they don't have proper collision maps, so it's possible under certain circumstances to fall through or walk through a semi-solid brush (usually if you're touching different parts of the same brush at once, like a single brush that serves as a ledge AND a wall). You can always change a semi-solid brush back to solid if any weirdness happens.

Last of all, you can always cover up a BSP hole by covering it up with a an Add brush (add a thin rectangular Add brush over the hole). It's not an elegant solution, but it works. images/icons/smile.gif

Like Bean mentioned earlier, using Zone portals to split up your level can increase the speed of the map quite a bit. Don't put Zone portals in the middle of a large room, you want to keep the surface area of the Zone portal as small as possible. Position Zone portals in connecting hallways or in out-of-the-way places where you will see them for as little time as possible.
You can put Zone portals anywhere, but ideally, position them in a spot where you can't see from the zone portal into both main rooms at the same time. Anyone who has created sectors-over-sectors in Build will have an instinctive idea on where to place them. images/icons/smile.gif

[ 12-01-2001: Message edited by: NutWrench ]