Five things to remember with vents:
1) If you want them to be see-through, you need to use the vents that start with " { "
Those are the ones with the blue in between the slats. The blue will be the part you can see through. Interesting side note... The only objects that have parts within them that you can see through start with this symbol " { " also! So you can browse your textures and just type " { " and it will show you all the ones you can see through. Anyway.
2) Choose func_breakable like eDan said. This will make it breakable.
3) Strength. The number corresponds with the number of hit points (or whatever) it will take to break it. If you want it to be broken easily, use a low number. A knife hit, like 15 or something. An awp, 100. If you want someone to empty a clip into it before it breaks, pick like 400.
4) Material type (or is it render mode..). Find the one that starts on "Normal." Change this to "Solid." If you don't do this, it won't work properly!
5) Fx Amount: If you don't do 255, then the slats that are SUPPOSED to show up WONT show up. 0 will make the whole thing invisible. If you're doing like a glass vent or something, it might be cool to set it to 100, but you would have to make a model for a glass, see-through vent. Waste of time.
So there you go! Do this and you will make a sweet vent! I personally like to have
some vents that take a while to break. Makes you think twice before doing it because it either wastes bullets, takes too long, or is loud and you're detected.
-Brandon
