DeviantPC has posted an article about creating a personalised Unreal Tournament 2003 level.
The Unreal virtual world is known as a subtractive space which means that as we define shapes we'd like to have in the world we have to subtract them from the world itself. Try to imagine the world as one big solid, with each object you subtract removing mass from it. In other words, you're not building rooms you're hollowing them out!Read more
