Quoth ladders emulate the func_ladder from Half-Life; they are created as a single invisible brush of any size, and players move when inside the trigger’s boundary according to their direction of facing.
Creating a trigger_ladder is very easy, since it is a simple trigger brush, but some things should be noted:
Most importantly, your ladder will be about 100% more friendly to climb if you set the “angle” for the trigger to point directly away from the surface it sits against. This makes sure that the ladder pulls you in when you touch it, launches you in the right direction when you jump off it, and pulls you onto the ledge above when you reach the top. If your ladder faces north remember to set the angle to 360, not 0.
If your ladder does lead directly to a ledge, to smooth the transition from climbing to standing, bring the top of the trigger_ladder bounding box to be flush with the ledge. Don’t forget the angle or this won’t help!
The player will grip if he touches the very edge of the trigger, so make it about 8 to 16 units narrower than the visible rungs of the ladder you build.
Ensure the trigger_ladder protrudes some short distance out from the rungs, so the player’s bounding box will collide with it. About 8 units should do.
Players are likely to be facing upwards upon reaching the top of a ladder and attempting to detach. Take care to construct the architecture at the summit of your ladder – and any other altitude where a destination is available – to assist player movement.
The sound effect for the player’s footsteps on the ladder rungs is set using the “noise” key. Default sound is metal rungs. Wooden rung sounds can be set with the value “player/ftladwd.wav”.
The sound made when the player first touches the trigger_ladder can be set in the same way using the key “noise1”.
Either sound can be set to any wav file.