VfxPhysicsOrbitModifier

Inheritance 1 ancestor · 14 siblings

VfxPhysicsModifierBase

Class Documentation

A physics modifier that makes the particles circle a centre. Each particle gets an orbit offset at spawn, which is the vector from the orbit centre to the particle, and an orbit rotational velocity, which is how fast that vector turns.

Spawn. The offset is InitialOrbitOffset, turned by InitialRotationOffset if that is set. The particle is displaced by offset * KeyedOrbitOffset.
Each step, before the integration. The radius vector is the stored offset times KeyedOrbitOffset. The angular velocity is InitialOrbitRotationalVelocity * KeyedOrbitRotationalVelocity, in degrees per second about each axis. The client turns the radius vector by the angle of this step and moves the particle by the difference, as a displacement.

Because the orbit is a displacement, it gives the particle no momentum. The particle's other motion moves the orbit centre.

Properties

ApplyDrag

Flag = true

16.1

Documentation Edit documentation

Lets the drag of a VfxPhysicsDragModifier slow the angular velocity. Without a drag modifier in the list the flag has no effect.

DragScaleFactor

F32 = 1

16.1

Documentation Edit documentation

Multiplier on the drag of a VfxPhysicsDragModifier when that drag slows the orbit. The fraction removed per step is drag * DragScaleFactor * dt, clamped to [0, 1].

InitialOrbitOffset

Embed<VfxVector3DynamicProperty> = { "Vector3": {} }

16.6

Documentation Edit documentation

Vector from the orbit centre to the particle at spawn, in world units, in the particle's reference frame.

InitialOrbitRotationalVelocity

Embed<VfxVector3DynamicProperty> = { "Vector3": {} }

Documentation Edit documentation

Angular velocity of the orbit, in degrees per second about each axis, evaluated once per particle at spawn. Required: if the driver is null, the modifier is skipped.

InitialRotationOffset

Embed<VfxVector3DynamicProperty> = { "Vector3": null }

16.7

Documentation Edit documentation

Euler rotation, in degrees, applied to InitialOrbitOffset at spawn. A random value here spreads the particles around the orbit. Left unset, the offset is not turned.

KeyedOrbitOffset

Embed<VfxVector3DynamicProperty> = { "Vector3": {} }

16.6

Documentation Edit documentation

Multiplier on the orbit offset, evaluated on every step. A curve here widens or narrows the orbit over the particle's life.

KeyedOrbitRotationalVelocity

Embed<VfxVector3DynamicProperty> = { "Vector3": {} }

Documentation Edit documentation

Multiplier on InitialOrbitRotationalVelocity, evaluated on every step.

OrbitOriginSpace

U8 = 1

16.6

Documentation Edit documentation

Which point the particle circles.

Value	Centre
`1`	The particle's own orbit centre, at `position - radius vector`. The centre moves with the particle's other motion.
other	The origin of the particle's reference frame, which is the emitter. The particle's whole position turns about it.

WorldSpaceRotation

Flag = false

Documentation Edit documentation

Treats the angular velocity as a world vector: the orbit axis keeps its world direction whatever the rotation of the particle's reference frame.