radial_influence

The radial influence applies an acceleration toward or away from a specified point. This also includes dropoff of effect with distance to that point, which will also affect any other influence nodes connected to this.

To use this node, plug its output into the influences input of a simulate node like simulate_aero, simulate_particles, or simulate_mpm.

Inputs

influence

One may optionally connect an influence field out_influence into this port. For example a mask_influence node could be connected to mask the effect of this influence. Any number of influence fields may be added to the daisy chain to build a complex field.

enable

Turn off to disable the effect. Disabling makes it a pass through node. Note that any other influence fields connected to the influence input port will still be active when this is disabled.

dropoff

This masks the amount of effect based on distance to the point. A dropoff of 0.0 will have full effect everywhere. A value of 1.0 will linearly decrease in effect with distance to center. Larger values will fall off more quickly. Note that this falloff is not as strong within within one or 2 units of distance. The formula used is (1.0/pow(distance+1.0,dropoff). Note that one could use this as a point distance mask for other influences by setting the magnitude to zero so no acceleration is applied.

center

This is the origin position of the radial acceleration. The dropoff is based on the distance to this point and the acceleration is either towards or away from this point.

magnitude

This is the strength of acceleration to apply. Positive values push away from the center, and negative values push towards the center.

You can connect a float, ScalarField, float3, or VectorField. VectorField and float3 values modulate the effect differently in each axis.

drag

This will dampen the current simulation velocities, resulting in less velocity buildup over time. High values of drag will fully replace simulation velocity with the radial acceleration, instead of continually adding in the acceleration. You can connect a ScalarField to vary the effect over space.

Outputs

out_influence

An output influence object that one can connect to simulation nodes or other influence nodes.