How to Prevent Crashes in DoomEdit

Originally written by gleeful on http://forums.thedarkmod.com/topic/2783

As soon as a map reaches a certain size, you are very likely to experience crashes when rendering it in the editor. that's because it is rendering the whole map at once and the editor is already eating up lots of your system's resources.

There are two easy things you can do about that:

1. Turn on Cubic Clipping (View > Cubic Clipping, Shortcut: CTRL+\).
2. Draw a brush around the desired area and select Region > Set Brush - this will temporarily cut away everything not inside the brush from your map. Region > Off will restore it of course.

You can also hide things (by pressing h) which you don't need to see in the render. SHIFT+h will make them re-appear.