Houdini 20.5 Nodes Geometry nodes

Convert VDB Points geometry node

Converts a Point Cloud into a VDB Points Primitive, or vice versa.

Since 16.0

The Convert VDB Points SOP converts an unstructured cloud of points to and from a single VDB Points primitive. The resulting primitive will re-order the points to place spatially close points close together. It is then able to efficiently unpack regions of interest within that primitive. The VDB Points Group SOP can be used to create regions of interest.

Because nearby points often have similar data, there is the possibility of aggressively compressing attribute data to minimize data size.

Parameters

Conversion

Controls if the node is packing points into a VDB Points primitive, or extracting points out of such a primitive.

Group

The VDBs to extract points from.

VDB Points Group

The point group inside the VDB Points primitive to extract. This may be a normal point group that was collapsed into the VDB Points primitive when it was created, or a new group created with the VDB Points Group SOP.

VDB Name

Name of the VDB Points primitive created.

Define Transform

An important consideration is how big to make the grid cells that contain the points. Too large and there are too many points per cell and little optimization occurs. Too small and the cost of the cells outweigh the points.

Using Target Points per Voxel

Attempt to size the voxels so the given number of points ends up in each voxel. This will assume uniform distribution of points.

Using Voxel Size Only

Provide an explicit voxel dimension.

To Match Reference VDB

Use the second input’s transform.

Voxel Size

The desired voxel size of the new VDB Points grid.

Points per Voxel

The number of points per voxel to use as the target for automatic voxel size computation.

Reference VDB

Which VDB in the second input to use as the reference for the transform. If not set, will use the first found VDB.

Position Compression

The position can be stored relative to the center of the voxel. This means it does not require the full 32 bit float representation, but can be quantized to a smaller fixed point value.

Mode

Whether to transfer all point attributes, or only those that are explicitly listed.

Point Attributes

Attribute

Name of point attribute to include in the VDB Points primitive.

Value Compression

How to compress the attribute.

None

The attribute is stored with its full precision.

16-bit Truncate

The attribute is stored at half precision, truncating lower order bits.

Unit Vector

The attribute is treated as a unit vector. This assumption means that when two values are known, the third is implied.

8-bit Unit

The attribute is treated as lying in the 0..1 range and converted to 8bit.

16-bit Unit

The attribute is treated as lying in the 0..1 range and converted to 16bit.

Blosc Compression

Enable Blosc compression of the attribute. This is a lossless compression codec that is effective with floating point data and is very fast to compress and decompress.

Normal Compression

All normal attributes will use this compression codec.

Color Compression

All color attributes will use this compression codec.

See also

Geometry nodes