Mapping/Checklist

This is a quick checklist of best practices, common pitfalls, hints and frequently asked questions regarding maps.

UFORadiant usage

To select func_group, select one brush of the func_group, then press CtrlAlt E. See func_group description for more hints on grouping brushes.
To create holes in existing brushes, create a brush where you want the hole to be, select it and press Shift U. Remove the temporary brush afterwards.
Brush splitting
Remember that results of object rotation depend on chosen grid size - rotating with different grid sizes will result in different object placement.
Do not apply flags with whole brush selected if there are any flags that differ for the faces of this brush. Radiant will reset parameters for all faces in this case.

"actorclip" brushes should always be aligned at lower boundary (0, 64 and so on).
Spawn points should always be aligned to 32 unit grid in x/y directions.
"actorclip" brushes that are meant to prevent actors from stepping on a tile altogether should always cover full 32 unit in x/y directions.
Walls, railings and other things should be aligned with the 32 unit grid in such a way that they are between 32 unit tiles and occupy no more than 4 units on each direction.
Floors should be in relative height 0-4 (0-4, 64-68 etc) and never below absolute heigth 0.

Assign "func_breakable" to individual brushes only (note, there might be some exceptions - for example, fueldump map).
Don't make stairs steeper than 45 degrees. don't make steps too large, they will get in the way.
Always set your levelflags, even if you think that setting none and having the brush appear in all levels will work for you. even if your map has only 3 levels, set levelflags up to 8th level, if the brush should be visible in higher levels. Otherwise adding a new level above or below existing ones will be near impossible.
If you want to copy an object from another map, copy it from prefabs, if available - prefabs are most likely to have latest fixes to the object that could be yet not in the other maps.

Some of the hints at Mapping/Testing might be useful in map fixing.