Houdini 21.0 Nodes Copernicus nodes

Pyro Uniform Force Copernicus node

Applies a uniform force.

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Since 21.0

This operation applies a uniform force to a velocity VDB.

Parameters

Signature

The VDB type that the source accepts.

See Signatures for more information.

Force

Operation

How to mix the force in with the incoming velocities.

Set

Replace the velocities with the force value.

Force

Add the force to the incoming velocities.

Drag

Treat the force direction as a velocity and blend the incoming velocities to it.

Scale

A global scale on the amount of force to apply.

Direction

The direction to apply the force. In drag mode, this is the velocity to drag to.

Scale by Timestep

Scale the effect of the force by the timestep. This ensures that the amount of force stays the same when substepping occurs, but if the instantaneous value needs to be computed, it can be turned off.

Mask by Threshold Field

Mask out the effect of the force by the threshold field. Threshold fields are intended to provide harsh on/off effects, but the range can be used to soften the transition.

Mask by Control Field

Mask out the effect of the force by the control field. Control fields are usually used the same way as masks, so represent a smooth engagement of the effect.

Mask along Axis

It is common for effects to be scaled along one particular axis. Rather than requiring the construction of VDBs to represent this; this allows the direct specification of the world space range over which the effect is to be scaled.

Inputs

v

Vector VDB to use as the original velocities.

direction

A Vector VDB allowing per-voxel control of the force direction.

threshold

A Float or Vector VDB to use as a threshold field. If it is a Vector VDB, its length is used.

control

A Float or Vector VDB to use as a control field. If it is a Vector VDB, its length is used.

Outputs

v

The modified velocities after uniform force is applied.

See also

Copernicus nodes