View source for Particle movement

'''Particle movement''' operators refer specifically to translation. Rotation is kept separate, since many particle systems don't want it.

== Movement Basic ==

''Moves particles with their internal velocities.''

; gravity
: A global force which accumulates over each particle's lifetime.
; drag 
: How resistant the particles are to motion. 1 means almost total resistance. Anything above 1 flings the particles off into outer space!
; max constraint passes
: {{todo|Unknown. Similar to the value on [[phys_constraintsystem]]?}}

== Movement Dampen Relative to Control Point ==

''Drains a particle's internal velocity as it approaches the specified control point. If no other forces are acting on it, the particle will eventually stop.''

''This can be used with [[#Movement Lock to Control Point|Movement Lock to Control Point]] (and its ''distance fade'' property) to have a control point "capture" particles near it then draw them along. It can also lock endpoints of a line of particles while allowing the middle section to move freely.''

; control point number
: The control point to dampen near.
; falloff range
: The distance over which the dampening effect will fade out to nothing.
; dampen scale
: The strength of movement dampening. This is ''not'' a maximum value; the effect will continue for as long as a particle is within range. {{todo|What is the units/second equivalent of 1?}}

== Movement Lerp to Hitbox ==

''{{todo|Smoothly move to a hitbox location? Something to do with the [[interpolation]] of remote players?}}''

; control point number
; lifetime lerp start
; lifetime lerp end

== Movement Lock to Bone ==

''Works like [[#Movement Lock to Control Point|Movement Lock to Control Point]], but is designed for use in conjunction with [[Position on Model Random]] initializer. Locks all particles emitted from a given control point to their associated bone.''

; control point number
: The control point that references the model in question.
; lifetime start/end fade
: The time at which to start/end fading the lock relative to particle lifespan (0-1).

== Movement Lock to Control Point ==

''Causes particles to inherit the movement and optionally rotation of a [[Control Point (particles)|control point]].''

; control point number
: The control point to lock to.
; distance fade range
: The maximum distance at which the CP will scoop up particles. A gentle falloff gradient is used. {{note|Using both ''distance fade range'' and ''lock rotation'' will result in particles spiralling in towards the CP until they stop moving.}}
; lock rotation
: Makes the particles respond to CP rotation as well as translation. Starts disabled.
; start_fadeout_min
; start_fadeout_max
; start_fadeout_exponent
; end_fadeout_min
; end_fadeout_max
; end_fadeout_exponent
: Defines when particles start and stop being affected by the movement lock, as a proportion of their lifespan. The exponent values are [[normal]]s which bias which result from the fade in/out range is most likely to be picked. {{bug|If there is a wide gap between the min and max fadeout times, some particles will continue to judder after they should have stopped.}}

== Movement Maintain Offset ==

''Positions particles in a straight line relative to one another.''

; Desired Offset
: The gap between each particle in units (but see ''Scale by Radius'').
; Local Space CP
: {{todo}}
; Scale by Radius
: Multiplies ''Desired Offset'' by the radius of the particle.

== Movement Maintain Position Along Path ==

''Arranges particles into a line between two control points, accounting for the movement of either.''

; maximum distance
: How far away either end of the path can trail from its control point. See also ''cohesion strength''.
; use existing particle count
: Map the current number of particles in the system to the path, overriding the manual value. Recommended, as getting the number wrong leads to flickering.
; cohesion strength
: How strong the attachment to each control point is. At 0, the path will have to be dragged. At 1, it will never stray from the CPs.
; start control point number
; end control point number
; bulge
; bulge control
; mid point position
; maximum distance
; particles to map from start to end
: See [[Position Along Path Sequential]].

== Movement Match Particle Velocities ==

''Forces particles to inherit the velocity of the first one emitted. Can copy the recorded value to a control point.''

; Control Point to Broadcast Speed and Direction To
: The given CP is moved to a position that represents the current velocity.
; Direction Matching Strength
; Speed Matching Strength
: Two [[normal]]s which determine the degree to which emitted particles match the first. Can both be set to 0 if you just want the CP output.

== Movement Max Velocity ==

''Limits the speed of all particles in this system.''

; Maximum Velocity
: Limit to this value.
; Override Max Velocity from this CP
; Limit to the first value of this control point's position vector.

== Movement Place On Ground ==

''Tries to ensure particles float above a surface somewhere beneath them. See also the [[Position Modify Place On Ground]] initializer.''

; collision group
: What to consider solid. {{todo|Values? <code>NONE</code> seems to mean everything.}}
; CP movement tolerance
: {{todo}}
; include water
: Consider water a valid ground surface?
; kill on no collision
: Remove the particle if it can't find the ground.
; max trace length
: How far down to search for the ground.
; offset
: Height above ground to float.
; reference CP 1
; reference CP 2
: {{todo}}
; trace offset
: {{todo}}

{{FakeCategory|Particle operators}}