whats the deal with overlaps?

[NACF URBAN]

ive been told many-a-time that i have many overlappping brushes. What exactly is the problem. if there is one howcome there are ones in stock Multiplayer maps such as decals

[Random]

Stock maps are done by folks that are no smarter or better at mapping that most of the really good ones around here. And even the best of us screw up once in awhile plus they throw them together really quickly and dont have time to edit like we do.

But why is it a problem, well if you are anal like me then you just go berzerk when you see it cuz you know its not right.

Why is it not right you ask? Lots of overlapping brushes can really screw you up when compiling maps (or so ive heard ive never overlapped a brush to tell you the truth so i wouldnt know.) I would have to get my reference manuals out to give you a perfect answer but lets just say for now it has something to do with screwing up your vis data.

What is compiling and vis data you ask? Well lets just see how you absorb the first parts and then move onto the rest later.

Random

[Balr14]

It causes excessive splits, which means more leaf portals. It may cause the length of the view portal chains to be longer. It may cause z-fighting (depending on how the brushes overlap). This does not apply to mesh surfaces (aren't decals usually applied to mesh?). Meshes are always treated as detail and are not included in vis calculations; there you need only worry about visible face count. The engine (any engine) has a fairly difficult time calculating visible faces from brushes. Don't make it work any harder than it needs to. MOHAA, RTCW:ET and CoD are the last of the brush based rendered games. All the newer games are entirely mesh based.

[tltrude]

It also looks bad because of the "Z-Fighting"--game does not know which texture to show. You can overlap patch mesh and lod terrain with brushes.