weapon_custom_beam

Beams are similar to bullets, except that they can bounce off walls and have advanced visual effects.

It might look like this entity has a lot of keyvalues, but many of them are similar or duplicates (since there are 2 beams with 2 alternates that you can customize).

Keyvalues:

Keyvalue Value Type	Description
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Beam Impact Frequency string	Delay between impacts when the beam is constant.
Beam Impact Sprite string	Sprite to display when the beam hits something that takes damage (monster or breakable entity).
Beam Impact Sprite Scale float	Size of the impact sprite.
Beam Impact Sprite FPS float	Frame rate of the impact sprite.
Beam Impact Sprite Color Color	Color and opacity of the impact sprite.
Beam Ricochet Limit integer	Maximum number of ricochets allowed for the beam.
Beam 1 Type integer	Visual style of the primary beam.
Beam 1 Duration float	Time to display the beam after shooting. If set the 0, the beam is made constant and will stop only after the shoot button is released (or if out of ammo or under water).
Beam 1 Sprite string	Sprite used as a texture for the primary beam.
Beam 1 Color Color	Color and opacity of the primary beam.
Beam 1 Width integer	Size of the primary beam.
Beam 1 Noise integer	Distortion of the primary beam.
Beam 1 Scroll Rate integer	Texture scroll speed of the primary beam.
Beam 1 Alt Color Color	Alternate color for the primary beam.
Beam 1 Alt Width integer	Alternate size for the primary beam.
Beam 1 Alt Noise integer	Alternate distortion for the primary beam.
Beam 1 Alt Scroll Rate integer	Alternate texture scroll speed for the primary beam.
Beam 1 Alt Interpolation integer	Choose how to animate the primary beam to and from its alternate settings.
Beam 1 Alt Interpolation Time float	The length of the primary beam animation.
Beam 2 Type integer	Visual style of the secondary beam.
Beam 2 Duration float	Time to display the beam after shooting. If set the 0, the beam is made constant, but only if the primary beam is also constant.
Beam 2 Sprite string	Sprite used as a texture for the secondary beam.
Beam 2 Color Color	Color and opacity of the secondary beam.
Beam 2 Width integer	Size of the secondary beam.
Beam 2 Noise integer	Distortion of the secondary beam.
Beam 2 Scroll Rate integer	Texture scroll speed of the secondary beam.
Beam 2 Alt Color Color	Alternate color for the secondary beam.
Beam 2 Alt Width integer	Alternate size for the secondary beam.
Beam 2 Alt Noise integer	Alternate distortion for the secondary beam.
Beam 2 Alt Scroll Rate integer	Alternate texture scroll speed for the secondary beam.
Beam 2 Alt Interpolation integer	Choose how to animate the secondary beam to and from its alternate settings.
Beam 2 Alt Interpolation Time float	The length of the secondary beam animation.
Constant Beam Ammo Cooldown float	Delay between ammo uses when the beam is constant.
Constant Beam Sound weapon_custom_sound	Sound to play (looped) when the beam is constant.
Constant Beam Sound Delay float	Delay before playing the constant beam sound.
Constant Beam End Sound float	Sound to play when the constant beam has stopped.

See the Shoot Entities page for the common keyvalues and flags that this entity uses.