Prefabs are the core of a map's design after floor layout. You can do anything with prefabs, as long as it makes sense. The best way to determine the proper use of prefabs is to understand what the developers have done and create your own stuff using what you have been given as examples. I would suggest taking lots of screenshots of prefabs. When I was first trying to understand how different sets of prefabs connected with each other, I took screenshots... lots of them. I currently have over 90 pics that are nothing but shots of prefabs. Those shots have given me a great understanding of how they are used and where. Now you have the ability to obtain the advantage of my experience.

There are basically two types of prefabs. Those that have collision lines on them and those that don't. Typically, those that don't have collision lines are large prefabs that typically stay outside of your floor layout. However, there are some larger prefabs that do have collision lines and there are smaller prefabs that don't have collision lines. If you want to use a larger prefab that has a collision line you will first need to make sure that your map is large enough to fit it in properly. The only way you can test that is to create the prefab in question and see how big it is in relation to your map. If you feel it would work in your map leave it in, but if not you can either get rid of it or make the map large enough to fit it in.

Large building prefabs like the Commerce(C1) set of buildings and the prefabs in the Outside set are the type of prefabs you would want to place as exterior buildings.

Prefabs also have render priorities. The render priority tells the game on which background detail settings to render (or display) certain entities.

The priority levels are broken down like this:

• 2 - Always - This setting makes the prefab always render. The prefabs that you would set this to are for the prefabs in the map floor and that make up the core design of your map. This is for those that have their graphics settings on low and need just the bare minimum to play. Other prefabs that require this setting are the node covers that go over the floor points in a map.
• 1 - Medium - This setting is for prefabs that are not necessary to be seen on low details but add ambiance to the map when seen at the next highest level.
• 0 - High - This setting is for prefabs that fit neither of the previous two conditions. Prefabs that need this render priority are those that are outside of or underneath your map floor and include large exterior buildings, tubes, and building connectors. In my maps, I usually set anything that is outside of the floor to this render priority.