I'm using Gtkradiant 1.5 and having an irritating time dragging the corners of a brush to the shape it needs to be. When a vertices is moved some other vertices move also. Is there a way of locking the positions of vertices so that when another vertices is moved the rest of the brush doesn't transform?

I'm no expert on Gtkradiant but I think I know what the issue is:All brushes must be CONVEX so sometimes vertices move automatically to compensate.
If you have something complex you want placed in a map you should model in a 3d program, export it in the .ASE format and import that into Gtkradiant. If you want an adventureous Gtkradiant-only approach, you can attempt to build it out of patches.

ihsan wrote:All brushes must be CONVEX so sometimes vertices move automatically to compensate.

While that is true and I understood it happening it does not require that so many points move to compensate. A face that has four vertices only needs one vertices to move if another is displaced to remain planar. If you could lock two vertices on the face in place and move a 3rd then the 4th would move to compensate. Instead what it does is move all of the 3 other vertices. It's not a major issue as I'm only using it for playerclip but it does look a bit odd in radiant.

Maybe you should use the boolean feature to carve the shape you want. Usually that approach solves it for me.

Oooh .. carve... I love that Morfar can back that up