Compiling a map can take WED from some seconds up to many hours or even days. It depends on the design of the map, and on the number of blocks and lights used. It's a square dependency - that means if you double the number of blocks, building normally takes four times as long. An indicator for the build time is the number of portals displayed during the build process. Portals are the planes that separate the regions (sectors the BSP process splits the level into). Each surface of a block can generate a splitting plane, and thus produce one or more portals. Scaling a block can increase, or decrease the number of portals.

If you get more than 5,000 portals, try to reduce your level - e.g. by replacing prefabs by map entities or Detail blocks. If you really want to build extremely huge levels, your PC should be equipped with a lot of RAM - we recommend at least 128 MB for up to 10,000 portals, and 256 MB for 15,000 portals. In preview mode (Visibility off) the level builds much faster, but then the WMB file is not optimized, resulting in a lower frame rate. The shortest build time is achieved by setting Visibility off and Light low quality simultaneously.

Levels should be compiled with Visibility off and Light low quality during development, and with both set to on and high quality for the final version. Each printed dot in the portals and the visibility calculation means 20 portals, so you can see how much dots will still be needed. The time per dot can't be easily predicted, though, and will be much larger for the last than for the first dots. If you have a very large level, but don't have the time for final compilation, compile with Visibility off, but Light high quality.