Making Trim
Trim is simply another term for "edging". Take a look at the ledges and edges of surfaces and platforms within any map and you will see that the texture around the edges is different to that used for the main floor texture.
Trim helps break up the floor textures used and when done well can make the level look much "cleaner". It can also make the level look more plausible; see-through walkways with solid edges for supports for example.
Subtractive trim
(First of all, can someone explain *what is trim*?)
The basic idea is that if you want trim around the base of a room, flush with the wall:
- make a subtract (What is a "subtract"? If you mean "subtractive brush" you should say that. "Subtract" is a verb.) the same base size as the room, and 32 high. (<– If it's the "same base size" as the room why is it only 32 high? Shouldn't it be the "same width and length as the room but only 32 high"?) Subtract this, and make the room brush smaller too so they don't overlap. (<— Subtract this from what? How can you subtract this brush from an empty space? I don't understand this explanation.)
- alternative method: use clipping to split the room subtract 32 units above the floor. (NB split, not clip – produce two brushes)
This technique is useful for walkways and ledges too: instead of subtracting a large room & adding in a ledge, subtract 3 brushes:
- below the ledge
- above the ledge
- and a ledge-thickness piece sandwiched in between
This gives you free trim all the way around the room, but there can only be one direction for the texture. If your trim needs to be directional, try seperate pieces by making trim with the extruder.
Related Topics
Discussion
EntropicLqd: If you do it this way don't add a zone portal at the point the two subtract brushes meet. I did that once and my level got flooded with lava 
Took ages to figure out what was causing it.
Tarquin: I can't see how that could have been the problem. Zone Portals can cut across several subtracts.
EntropicLqd: Me neither - but I moved the zone portal down by 8 units and it was fine after that. Here's a small diagram of what I had prior to moving the zone portal down:
| | | | +- Zone portal at join -+ | | | |
The + symbols show the point at which the subtract brushes met. They were adjacent and all the rest of it. It's possible that it was the rebuild that solved the problem - but then why didn't the other zillion previous rebuilds do the same? Dunno m8.
