modulate_influence
The modulate influence allows one to use a simulation property to scale the amount of effect applied by other influence nodes. This node is similar to the mask_influence, but generates the mask values using a simulation property instead of the distance to geometry. This is frequently very useful. For example one could modulate a gravity_influence using the aero property voxel_fog_density. This would create an effect similar to aero buoyancy, but using density, not temperature. If one instead applied the gravity force without this modulation it would apply an acceleration to all voxels(including empty air), not just the ones with density in them, so the fog would not move relative to the air.
To use this node, plug its output into the influence input of an influence node like wind_influence. This node will have no effect unless combined with other influence nodes.
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. Note that this will also modulate any influences connected to this port.
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.
property
The name of the simulation property to use for the influence. The property currently must be a float or a float3. In the case of float3 properties like point_velocity the magnitude of the property is used to scale the influence effect. So for example this could be combined with a drag_influence to apply more on particles only when the point_velocity is high.
use_gradient
If enabled then the gradient (or slope) of the property will will be used. Currently this only works with volume properties, such as voxel_temperature for an aero_simulation. One could, for example, use the gradient of voxel_temperature in an aero simulation to modulate vorticity. Places in the simulation where the temperature changed dramatically across a voxel would thus get more vorticity.
min
This is the min value of the simulation property below which any connected influence nodes will have no effect. The effect increases linearly until the property value is at the max value, where connected influences will then have full effect.
max
This is the max value of the simulation property beyond which any connected influence nodes will have full effect.
invert
This reverses the effect of this influence. When enabled then simulation property values below the min will result in full effect and no effect when beyond the max.
Outputs
out_influence
An output influence object that one can connect to simulation nodes or other influence nodes.