Win32, OpenGL and ODE Physics

FreeWorld Tutorial

By Alan Baylis 21/07/2003

Adding and Carving Brushes
 
When adding brushes you can add both convex and concave brushes. When carving the cutting brushes must be convex as the brushes produced will be illegal if you cut with a concave brush. One difference between this editor and other editors is that a concave brush will be produced as a result of the carve rather than a group of convex brushes, this was done because the next update of the editor will allow carving with concave brushes. I will add here, for those that are interested, that the carving of a concave brush is done by first partitioning the brush into convex areas and creating temporary portals to fill in the missing faces along the partitions. If you want to see how the brush was partitioned press T to toggle the test mode, the perspective window will display a wire frame view of the last brush to be carved in yellow and show the portals as blue faces. As the brush to be carved becomes more complicated then the longer it takes to carve it due to the partitioning process. For this reason I recommend that you make your world in a modular way, constructing small building blocks and saving them to a brush file, rather than adding and carving one big world brush. Also, there is little need to add the brushes together for the same reason above, all the brushes are added together and have the redundant polygons removed before the final creation of the world data.