User:Mattshu/sandbox
This tutorial will walk you through the basics of adding a laser beam with relays and a catcher to your Portal 2 map.

Creating the beam
First you'll need to create the base for the laser. If you're attaching the laser to the wall, you'll need a 64 x 64 x 32 space in the wall.
Then create a new entity named env_portal_laser and create the following keyvalues:
Key Value StartState 0 angles 0 90 0 skin 0 AutoAimEnabled 1 model models/props/laser_emitter_center.mdl drawinfastreflection 0 LethalDamage 0

Using Hammer's handles (the X marks you see that shows the center of a brush), line up the new entity inside your hole. Make sure the laser is pointing in the direction you'd like it to.
Creating the relay
This also requires a 64 x 64 x 32 hole.
Create a new entity and name it prop_laser_relay with the following keyvalues:
Key Value angles 0 0 0 model models/props/laser_receptacle.mdl targetname name of the catcher (required for logic entities) vscripts laser_target/musical_laser_catcher.nut

As done before, line up the entity with Hammer handles, but raise it so it will be lined up with the real floor surface.
Creating the catcher
Once again, create the standard 64 x 64 x 32 hole in your wall.
Create a new entity and name it prop_laser_catcher with the following keyvalues:
Key Value angles 0 0 0 model models/props/laser_catcher_center.mdl skin 0