Force Field: Spin

A force field that applies forces to rotate rigid bodies around a line, defined by a spin axis, and varies with the function coefficients. Positive values rotate clockwise around the spin axis when looking along the axis. The net force on the rigid body is calculated using f = constant + linear ‘*’ r + inverseSquare / r^2.

The spin force field generates forces that cause physics objects to spin around a line. No force is applied along the direction of the spin axis. The only difference between this force field and the linear force field is the direction of the resulting force. This linear force field generates forces towards the line, while the spin force field generates forces that are perpendicular to the line. 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
spinAxis	normalf[3]	The axis around which rigid bodies are rotated in world coordinates.
shape	token[]	Derive the position input from this prim instead.
constant	float	constant applies a steady force.	0.0
linear	float	linear sets a force that varies with distance to the center.	0.0
inverseSquare	float	inverseSquare sets a force that varies with the reciprocal of the square of the distance to the center.	0.0