Also, could there be a way to make projectiles bounce off respawnroomvisualizer?
I saw it before on maps like Trade_Plaza, where although bullets could go in, the projectiles like rockets and stickies couldn't.
Sounds like they were using a
func_clip_vphysics brush. Those stop stickies, grenades, jarate, milk and sandman balls from passing though but
not rockets. Rockets (
and other explosives) can be countered with
func_nogrenades.
You could also copy Valves own method for protecting MvM bots, by giving them an uber while in their spawn area. For that you'd use a
trigger_add_tf_player_condition brush and set it to either 5 (TF_COND_INVULNERABLE) or 51 (TF_COND_INVULNERABLE_HIDE_UNLESS_DAMAGED), the 2nd one being the one Valve uses on MvM bots.
However when it comes to spawn rooms you're better off using simple world brushes to stop projectiles from getting too far in. So long as player don't have a direct line of sight into where enemy players will spawn, and there is a buffer zone where any projectiles will be caught/contained, then the players inside should be fine.