This is basically an invisble func_wall that can be toggled on and off indefinitely.
The “noise” key is used to specify the sound effect played when the wall is triggered and “noise1” is for the sound played while the wall is actually blocking the player’s movement. “noise2” is the sound to play when a player touches/takes damage from the wall. Add these in the format “weapons/lhit.wav” ( the “/sound/” bit is automatically added by the engine ). The wall can also be set to inflict damage on the player every “wait” seconds, with “dmg” specifying how much damage per hit. Default values are 0.5 and 0 respectively.
Spawnflag 1 means that the wall begins non solid, and will become solid once triggered. Spawnflag 2 turns on the particle effect, making this into a forcefield. While the func_togglewall is solid, a particle effect will scroll across it. The “worldtype” key takes values from 0 to 5 specifying the direction the effect scrolls;up, down, east, west, north or south,. The “color” key should be a quake palette index specifying the colour of the particles. “speed” specifies the speed at which the wave should travel. “style” specifies the number of particles that should be generated per second. Take care that style is not set too high, or the player will be flooded with particle messages, causing lag in network games.
If the wall does not have a particle effect, spawnflag 4 will change the type of solid object that the func_togglewall is. By default a func_togglewall blocks line of sight to monsters and has a shape matching the brushes it is built from. With spawnflag 4 it does not block line of sight and has a bounding box shape like a trigger, so it is a cuboid aligned to the axes of the world large enough to cover the whole extent of the brushes it is made from. If you are using this spawnflag, construct the object from a single, unrotated cuboid brush to see the shape of it correctly.
Sometimes it may not make sense for monsters to remain unalerted behind a func_togglewall. If you cannot use spawnflag 4, it is recommended to alert the monsters by triggering them.