Post Posted: 05 Jun 2015, 18:41
Want to make an elevator with doors that automatically open when the elevator is at a certain position without a ton of bullshit? Easy! Attach a knife to the elevator, then add triggers with Trigger Type set to ClassProximity, and specify Knife as the class. Then add these triggers to different positions where doors should open. Set the doors to TriggerControl and boom, you have doors that open when your elevator stops somewhere. Adjust collision on the knives and triggers for enhanced precision.
You can do similar things with this method, like attaching a knife to a train for each set of the wheels, then add triggers to parts of the tracks where there should be bumps. Have the bump hit triggers trip a special event to play a sound, and now you can hear when your train is banging against shit on the rails. Add a very low magnitude earthquake for added effect if you are feelin' saucy.
Invisible collision hulls being a pain in the ass with BSP holes? Don't use cubes. Use a square shape from the 2d shape editor extruded to a point, forming a pyramid. Why? It's fewer nodes (less ways to fuck up and fewer cuts), there's only one square face (triangles are virtually impossible to break by vertex editing), and it makes the borders of the brush come to points instead of sides. You can fit these into very tight spaces and only have five vertices to edit instead of eight, which is way easier to do by hand. You can flatten the thing down to 1 unit wide by compressing the point, and it's as good as a 1-unit-wide cube without the drama. Don't forget to merge the polys on the flat side, though!
Also: make them semisolid if you need them to penetrate geometry but don't want to see holes in the world. I.e. if you're trying to cover areas where ordinarily you'd have to make a lot of smaller ICHs in order to fill gaps, like X-beams supporting a masked grate texture. Make one big one, cover all the gaps, and make it semisolid. When you rebuild, you won't see the brush penetrating the solid geo like you would with a solid ICH.