Force Field: Linear¶
A linear force field that attracts and/or repels rigid bodies from a line, defined by a point and direction vector, depending on the function coefficients. Positive values attract and negative values repel. The net force on the rigid body is calculated using f = constant + linear ‘*’ r + inverseSquare / r^2, where r is the distance to the closest point on the line.
The linear force field generates forces that attract or repel physics objects from the closest point on a line. No force is applied along the direction of 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 

Connection to evaluate this node. 
0 
primPaths 

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

enabled 

Enable or disable this ForceField. Overrides all other settings. 
True 
position 

The location of the force field. 
[0.0, 0.0, 0.0] 
range 

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 

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 

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

The direction vector of the line. 

shape 

Derive the position input from this prim instead. 

constant 

constant applies a steady force. 
0.0 
linear 

linear sets a force that varies with distance to the center. 
0.0 
inverseSquare 

inverseSquare sets a force that varies with the reciprocal of the square of the distance to the center. 
0.0 