VfxPhysicsModifierBase
Inheritance 15 descendants
- VfxPhysicsModifierBasecurrent
- 0x402b2a8f
- 0x4a2445d4
- 0x8edc8e76
- 0xc685a3b6
- VfxPhysicsAccelerationModifier
- VfxPhysicsDragModifier
- VfxPhysicsFollowTerrainModifier
- VfxPhysicsGroundCollisionModifier
- VfxPhysicsOrbitModifier
- VfxPhysicsPositionModifier
- VfxPhysicsRotationModifier
- VfxPhysicsScaleModifier
- VfxPhysicsSimpleModifier (removed in patch 16.13)
- VfxPhysicsVelocityModifier
- VfxPhysicsWorldSpaceTranslationModifier (removed in patch 15.24)
Class Documentation
Edit documentationOne building block of the motion of a
VfxModularPhysicsComponent. Each entry of its
Modifiers list adds one kind of motion or one per-particle value: velocity,
acceleration, drag, an offset, a rotation, a scale, an orbit, attraction, noise, terrain
following or ground collision.
Initial and Keyed values
Most modifiers take their values in pairs of driver values:
- An Initial value is evaluated once per particle, when the particle spawns, and stored with it.
- A Keyed value is evaluated on every step and multiplies the stored Initial value, per component. Left unset it is 1, so the Initial value applies unchanged. A curve over the particle's age in a Keyed value shapes the Initial value over the particle's life.
The drivers of a modifier are evaluated per particle, on the particle's age, unless the modifier's page says otherwise. IVfxBaseDriver describes the time sources and the random values.
An Initial value is set by default. Most modifiers check only that their Initial driver is present: data that writes an explicit null in it turns that part of the modifier off.
Local and World values
A Local value is in the axes of the particle's reference frame. A World value keeps its world direction whatever the frame's rotation. VfxModularPhysicsComponent describes the frame and the flags that choose its rotation.
When modifiers run
- Spawn. After the component places the new particles, each modifier initialises them, in list order. This is when the Initial values are evaluated.
- Step, before the integration. The acceleration, drag, velocity, position, rotation, orbit, attraction, noise and ground-collision modifiers run in list order. They add to the step's acceleration and displacement, change the velocity, or set the rotation.
- Step, after the integration. VfxPhysicsScaleModifier and VfxPhysicsFollowTerrainModifier run.
The drivers of all modifiers are bound once, when the emitter is created.