Force Field: Wind

A force field that simulates an unsteady wind that pushes rigid bodies.

The wind force field causes physics objects to move as if they are blowing in a wind. The wind can vary in wind speed and direction. The following list of properties are available.

Installation

To use this Node, you must enable omni.physx.forcefields in the Extension Manager.

Inputs

Name

Type

Description

Default

execution

execution

Connection to evaluate this node.

0

primPaths

token[]

Apply forces to this list of Prims. Must be rigid bodies for the forces to have any effect.

enabled

bool

Enable or disable this ForceField. Overrides all other settings.

True

position

pointd[3]

The location of the force field.

[0.0, 0.0, 0.0]

range

float[2]

Forces are not applied when the distance to the force field is outside of this (minimum, maximum) range. Each force field can have a different definition of distance, e.g. for a spherical fore field, the distance is to the center, for a plane, the distance is to the closest point on the surface, for a line, it is to the closest point on the line. The minimum or maximum range is ignored if the value is negative.

[-1.0, -1.0]

surfaceSampleDensity

float

Number of rays to cast per square unit of cross sectional area. When Surface Sample Density is disabled, by setting this value to 0, all forces act through the Center of Mass of the Rigid Body and no rotational torques will be applied. Any positive value will enable Surface Sampling. Ray casts are performed against the Collision Object of the Rigid Body in order to apply forces on the surface along the direction of the surface normal. This will apply torques on the Rigid Body that will induce rotation. Higher densities will cast more rays over the surface and spread the same force over the surface area. More ray casts will generate more accurate forces and torques, but will take additional compute time.

0.0

surfaceAreaScaleEnabled

bool

Enable or disable scaling of forces by the surface area that faces in the direction of the applied force.

True

shape

token[]

Derive the position input from this prim instead.

drag

float

The drag coefficient determines how quickly the body moves along with the wind. Smaller values cause the body to react more slowly.

0.0

averageSpeed

float

The average speed of the wind. Speed changes are added to this base speed, but the net speed can never drop below zero.

0.0

averageDirection

normalf[3]

The initial direction of the wind in the world coordinate system. Wind direction changes are added to this base direction.

speedVariation

float

The magnitude of the random changes of the wind speed.

speedVariationFrequency

float

The frequency of the random changes of the wind speed.

0.0

directionVariation

normalf[3]

The magnitude of the random changes of the wind direction in the world coordinate system.

directionVariationFrequency

vectorf[3]

The frequency of the random variations of the wind direction in the world coordinate system.