mask_influence

The mask influence can be used to modify the amount of effect of other influence nodes using the distance to geometry. It will only have effect when combined with other influence nodes through the influence port. It should also have some geometry connected to the geometry port.

To use this node, plug its output into the influence input of an influence node like wind_influence. Also connect the geometry to use into the geometry port.

Inputs

influence

One may optionally connect an influence field out_influence into this port. For example a modulate_influence node could be connected to additionaly vary the effect based on a simulation property. Any number of influence fields may be added to the daisy chain to build a complex field.

geometry

This defines the geometry to use for the mask. This node will have no effect if there is no connection to geometry.

General

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.

geo_shape

This defines the method to use for the geometry distance.

• Mesh: Use the true distance to the input object. This method converts the input geometry to a volume distance field using the specified detail_size which may be slow for small detail_size values.
• Bounding Box: This replaces the geometry with an implicit box that bounds the input geometry.
• Bounding Sphere: This replaces the geometry with a perfect implicit sphere that fits to the inside bounds of the geometry bounding box.

resolution_mode

The resolution mode determines the units of geo_detail_size.

• In Automatic mode, geo_detail_size is interpreted in world-space units if geometry is points (i.e. like Absolute mode); otherwise geo_detail_size is interpreted as relative to the bounding box of the input geometry (i.e. like Relative mode).
• In Absolute mode geo_detail_size is specified in world-space units.
• In Relative mode geo_detail_size is specified relative to the bounding box of the input geometry.

geo_detail_size

This defines how finely to voxelize the input geometry when creating the distance field (or level set) to use for the mask. Smaller values will capture finer details of the input geometry but be slower and more memory intensive.

geo_volume_mode

Defines how an input mesh is voxelized.

• Solid: This mode voxelizes a polygonal mesh as a solid and works best if the mesh is watertight.
• Shell: This mode voxelizes the mesh as a shell and does not require the mesh to be watertight.

Mask Properties

magnitude

This is the overall level of effect for the mask. One may optionally connect a scalarField to this property. A value of zero will result in the influence having no effect while a value of 1.0 will generally have full effect.

min_distance

The distance to the geometry below which the level of effect will be full effect. Closed meshes like a sphere will work better than open meshes like a plane. Inside the geometry the distance become negative, so one can use negative values for min_distance to offset the point of full effect further inside a mesh.

max_distance

The distance to the geometry beyond which there will be no effect.

dropoff

This determines how quickly the effect falls off where the distance is between min_distance and max_distance. If it is 0.0 then all distances within max_distance will have full effect with zero effect beyond that distance. A value of 1.0 will be a linear falloff from full effect at min_distance to none at max_distance. A value of 2.0 will falloff by a power of 2. For higher values the force will fall off faster with distance.

invert

This reverses the mask when enabled. Thus with it enabled there would be full effect outside the geometry with no effect inside.

Outputs

out_influence

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