Houdini 22.0 Nodes Geometry nodes

Implicit Surface Evaluate geometry node

Evaluates implicit surface data into a VDB.

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Since 22.0

Samples data from an implicit surface at VDB voxel positions and writes the result into a VDB. The first input provides the VDB to write to and the second input provides the implicit surface geometry to evaluate.

You can optionally activate the target VDB around the implicit surface before writing values, with an optional world-space offset and a narrow band limit around the surface.

Parameters

Activate

Activates voxels in the target VDB before writing values.

When this is on, the activation region is based on the implicit surface from the second input. This is useful when the target VDB does not already have active voxels in the area where the implicit surface should be evaluated.

Offset

Expands or shrinks the activation region in world-space units.

Positive values expand the region away from the implicit surface. Negative values shrink it.

Band

Limits activation to a band around the implicit surface.

Half Width

Half-width of the surface band in voxels. Only used when Band is turned on.

Evaluate Velocity

Turn on to evaluate implicit surface velocity instead of a named source attribute.

The node computes the velocity data needed by implicitsurfacevel and writes the resulting velocity to the target volume. Turn off to interpolate the attribute specified by Source Attribute.

Source Attribute

Name of the implicit surface attribute to interpolate into the target VDB.

This is used when Evaluate Velocity is turned off. The attribute can be a float or vector valued attribute.

Target Volume

Name of the VDB in the first input to write to.

Inputs

VDB to Write

The target VDB that receives the evaluated values.

Implicit Surface

The implicit surface geometry to evaluate.

Outputs

Updated VDB

The input VDB with evaluated implicit surface data written into the target volume.

See also

Geometry nodes