Since 18.0

This node will import the USD primitives specified by the File and Primitives parameters. The imported primitives are represented as USD packed primitives, which can optionally be unpacked into normal Houdini geometry.

The primitives to be imported are specified by selecting the paths of one or more USD primitives, using a primitive pattern. Optionally, the USD hierarchy can be further traversed to import the descendants of these primitives that match a specific criteria.

Parameters

File

The USD file to import from.

Reload

Reloads the contents of the USD file.

Missing File

Specifies what should be done if the specified file (or a file referenced inside it) cannot be found. By default, if there is a missing or invalid file, the SOP will error. This can be troublesome in a network that can recover from the error. In these cases the behavior can be set to No Geometry so only a warning is posted.

Set Variants

If enabled, switches the currently selected variant in a variant set for the specified primitives. See Set Variant.

Number of Variants

You can perform multiple variant selections in a single Set Variant node. Set this to the number of selections you want to make, or use the plus and minus buttons to add or remove selections.

Choose Variant Set by Index

When this is on, you specify the variant set using a number representing the index of a variant set in the alphabetically sorted list of variant sets, rather than a name. If you are doing something like choosing a variant set using a random number generator, it’s easier to deal with variant sets by their index rather than their name.

Variant Set

The name of the variant set to select a variant from.

Variant Set Index

When Choose variant set by index is on, the index of the variant set (in an alphabetically sorted list of variant sets on the primitive).

Choose Variant Name by Index

When this is on, you specify the variant using a number representing the index of a variant in the alphabetically sorted list of variants, rather than a name. If you are doing something like choosing a variant using a random number generator, it’s easier to deal with variant sets by their index rather than their name.

Variant Name

If not choosing the variant by index, this parameter is the name of the variant that should be selected within the specified variant set. If this value is an empty string, any existing variant selection specified in the active layer will be cleared. This will “reveal” any variant selection opinions authored in weaker layers. If this value is set to the special string <block>, an explicit empty variant selection will be made, blocking any variant selection opinions from weaker layers, leaving the chosen set without any variant selected. If this is set to a list of variant names (' ' or ',' separated), then this will use the first one that matches a valid variant name in each prim’s variant set.

Variant Name Index

If choosing the variant by index, this parameter specifies the variant to select as an index into the alphabetically sorted list of variants in the variant set.

Primitives

The USD primitives to import. This parameter accepts any USD primitive pattern. Primitives that do not match the Purpose filter are excluded.

Traversal

Optionally, the USD hierarchy can be further traversed to import descendants of the selected Primitives that match a criteria.

Note

Equivalent behavior could also be achieved through a primitive pattern (for example, using the descendants auto collection).

No Traversal

Creates a USD packed primitive for each USD prim matched by the Primitives pattern.

Components

Creates a USD packed primitive for each prim with kind component.

Gprims

Creates a USD packed primitive for each gprim.

Groups

Creates a USD packed primitive for each prim of type group.

Create Path Attribute

When turned on, creates a SOP primitive attribute containing the scene graph path of the original USD primitive.

Create Name Attribute

When turned on, creates a SOP primitive attribute containing the name of the original USD primitive.

Display As

Specifies how to display the USD packed primitives in the viewport.

Full Geometry

The full geometry is displayed in the viewport.

Point Cloud

Only the points of the geometry are displayed. This takes less memory and is faster to render.

Bounding Box

Only display the bounding box of the geometry in the viewport.

Centroid

Display a single point at the center of the bounding box.

Hidden

Don’t display the geometry in the viewport.

Pivot Location

Specifies the packed primitive’s point position.

Centroid

Use the center of the world position of the USD prim’s bounding box.

Origin

Use the world position of the origin of the USD prim.

Purpose

Sections of a USD hierarchy can be marked to be used for a specific purpose. Only sections marked as the default purpose or one of the specified purposes are traversed when unpacking the USD packed primitives.

Unpack

Unpacks the packed USD primitives into normal Houdini geometry, or into packed USD primitives for the prims' descendants.

Geometry Type

Whether to output the extracted USD prims as a new USD packed primitive, or as Houdini polygonal geometry.

See also

Geometry nodes