The env_shooter entity, when triggered, shoots out a number of models or sprites, often used to create a spilling or bursting effect.
Name (targetname) - Name is a general attribute used to identify entities.
Pitch Yaw Roll (Y Z X) (angles) - Sets the pitch and yaw angles the particles will be shot out at. Roll does not seem to be used.
Number of Gibs (m_iGibs) - Sets the number of particles that will be shot out on activation.
Delay between shots (delay) - Sets the time in seconds between each particle being shot out. Has a lower limit of 0.1.
Gib Velocity (m_flVelocity) - Sets the speed that the particles are shot out at.
Course Variance (m_flVariance) - Sets how variable the angle of each particle can be. A value of 0 will have each particle travel at precisely the same angle, while larger values will vary the angle more.
Gib Life (m_flGibLife) - Time in seconds that the particles will linger before fading away.
Render FX (renderfx) - Gives the particle certain visual effects depending on Render Mode.
Normal (0) - No visual effects.
Slow Pulse (1) - Particle slowly pulses with transparency. Faint.
Fast Pulse (2) - Particle quickly pulses with transparency. Faint.
Fast Wide Pulse (4) - Particle quickly pulses with transparency. Strong.
Slow Fade Away (5) - Seemingly unused.
Fast Fade Away (6) - Seemingly unused.
Slow Become Solid (7) - Seemingly unused.
Fast Become Solid (8) - Seemingly unused.
Slow Strobe (9) - A very slow strobe effect between visible and invisible.
Fast Strobe (10) - A medium strobe effect between visible and invisible.
Faster Strobe (11) - A very fast strobe effect between visible and invisible.
Slow Flicker (13) - Particle flickers in and out of visibility.
Fast Flicker (13) - Particle quickly flickers in and out of visibility.
Constant Glow (14) - Seemingly unused.
Distort (15) - Particle has a slight fast pulsing of transparency, and occasionally translocates slightly. (Translocation visible with "Normal" Render Mode.)
Hologram (Distort + fade) (16) - Particle has a slight fast pulsing of transparency, and occasionally translocates slightly. (Translocation visible with "Normal" Render Mode.) Fades out with distance.
Render Mode (rendermode) - Allows special rendering modes to be applied to the given particle.
Normal (0) - Standard rendering. Render FX and FX Amount will generally have no effect.
Color (1) - Allows particle to become transparent.
Texture (2) - Allows particle to become transparent.
Glow (3) - Allows particle to become transparent. Will remove background from sprites. Sprites will appear larger and become more faint with distance.
Solid (4) - Allows particle to become transparent.
Additive (5) - Allows particle to become transparent. Models will be given a white glow. Will remove background from sprites.
FX Amount (1 - 255) (renderamt) - In all but "Normal" Render Mode, alters how transparent the particle is. Scales from 0 (invisible) to 255 (solid, normal).
FX Color (R G B) (rendercolour) - Alters the colour of sprites in all but Color Render Mode. Will have no effect if R, G and B are all equal.
Model or Sprite name (shootmodel) - This defines which model or sprite file will be shot by the entity. This accepts an input of the form "path/filename.mdl" (starting from the root folder). (Example: "models/can.mdl" or "sprites/glow01.spr")
Material Sound (shootsounds) - Sets which sounds the particles will produce when they impact on surfaces.
None (-1) - The particles will not make any sound.
Glass (0) - The particles will make a glass sound.
Wood (1) - The particles will make a wood sound.
Metal (2) - The particles will make a metal sound.
/Flesh (3) - The particles will make a fleshy, squishy sound.
Concrete (4) - The particles will make a rocky sound.
Gib Sprite Scale (scale) - Sets the scale of sprites, in the form of a size multiplier.
Gib Skin (skin) - Sets which skin of models the entity will use, if the model has more than one.
Repeatable (1) - If enabled, the entity can be triggered multiple times. Otherwise, the entity will be removed after its first trigger.
Exactly how the values of Course Variance change the angles is difficult to be precise with. A value of 0.15 will provide a decent spread while maintaining roughly the same direction. A value of 1 will be enough to have some particles be shot at an angle greater than 90 degrees away from the inital angle. A value of 255 will essentially ignore the Pitch Yaw Roll angles and fire each particle in a random direction.
While intended for small models and sprites, the env_shooter will fire whatever you give it. If you want it to fire something like human grunt models, it will do so happily. However, it should be noted that the models will be fired rotating randomly until they come to a rest, at which point the model will assume an upright position. Larger models will likely clip into surfaces until this happens.