im doing the basic beginner tutorial. i made a little arch shaped block, and i wanted to use it to cut a hole in the wall the same shape. but when i go under EDIT i cant click on csg subtracter.... why?

you must select the entity you are using to cut the wall

hope that helps =]

do you have an arch shaped block, or a arch shaped group?
wed can only create csg subtracts with single blocks.

if it is a group, read the tutorial for ungrouping,
ungroup your arch into single blocks, and now it should work...