How do you make template maps?

[Kaiser]

its hard to explain but when I opened those maps in the editor, it apperars that the city like maps are laid out on a huge flat sheet.....and when I checked the tutorial maps, I saw one that says "template_basic" how do you make that?

[Jwh]

Basically what they did for that was to make a huge room and mark every side but the floor 'portal'. Then they made a skybox to fill in the red space. There are tutorials for making skyboxes on Seriously! I think..