UsdGeometry

Overview

UsdGeometry generates geometry loaded from a USD file.


Attribute Reference

Curve attributes

base_width_factor

Float
default: 1.0

Multiplier for the radius of the base of curves

radius_mult

Float
default: 1.0

Multiplier for the radius of points and curves

tessellation_rate

Int
default: 4

Number of segments to split curve spans into

tip_width_factor

Float
default: 1.0

Multiplier for the radius of the tip of curves

Geometry attributes

reverse_normals

Bool
default: False

enable to reverse the normals in the geometry

side_type

Int enum
  0 = “force two-sided” (default)
  1 = “force single-sided”
  2 = “use mesh sidedness”

set single sidedness of the mesh, will affect the visibility of the mesh based on normal direction

Labels attributes

label

String
default:

label used in material aov expresssions

shadow_receiver_label

String
default:

Label used to associate Geometry objects into ShadowReceiverSets. Using this in combination with the ["shadow_exclusion_mappings"] attribute, shadows from specified geometries or their parts can be suppressed from casting shadows onto one or more specified sets.

Mesh attributes

adaptive_error

Float
default: 0.0

The maximum allowable difference in pixels for subdivison mesh adaptive tessellation (each final tessellated edge won't be longer than n pixels if adaptive error is set to n).A value of 0 disables adaptive tessellation, reverting to uniform tessellation, which sometimes is more stable in animation.Adaptive tessellation is not supported for instances.

mesh_resolution

Float
default: 2.0

The maximum resolution to tessellate a mesh. An edge on input face will be tessellated to at most n segments when "mesh resolution" is set to n. If "adaptive error" is set to 0, every edge on input face will be uniformly tessellated to "mesh resolution". Otherwise renderer will adaptively tessellate mesh based on camera information

smooth_normal

Bool
default: True

Generates smooth shading normals on a PolygonMesh when the mesh doesn't provide shading normals

subd_type

Int enum
  0 = “use mesh type” (default)
  1 = “force polygon mesh”
  2 = “force subdivision mesh”

PolygonMesh/SubdivisionMesh prim type to create.
"use mesh type" will use the type the Mesh prim specifies.
"force polygon mesh" will always resolve to PolygonMesh.
"force subdivision mesh" will always resolve to SubdivisionMesh.

Motion Blur attributes

curved_motion_blur_sample_count

Int
default: 10

Number of time samples generated along each curve when using curved motion blur

motion_blur_type

Int enum
  -1 = “best” (default)
  0 = “static”
  1 = “velocity”
  2 = “frame delta”
  3 = “acceleration”
  4 = “hermite”

Motion blur type for PolygonMesh/Points/Curves.
"static" will treat the mesh as static.
"velocity" will blur using the supplied vertex positions and velocities.
"frame delta" will interpolate between the two supplied vertex positions.
"acceleration" will blur using the supplied vertex positions, velocities and accelerations.
"hermite" will use supplied pair of positions and pair of velocities to interpolate along a cubic Hermite curve.
"best" will use choose the method which provides the highest quality given the available data.

primitive_attribute_frame

Int enum
  0 = “first motion step”
  1 = “second motion step”
  2 = “both motion steps” (default)

Which frame(s) do we take the primitive attributes from?
 O : first motion step
 1 : second motion step
 2 : both motion steps

use_rotation_motion_blur

Bool
default: False

If "xform" is time varying and motion blur is enabled, enabling this feature can produce a curved rotation trail. Enabling this feature will disable adaptive tessellation for this mesh

Ray Tracing attributes

ray_epsilon

Float
default: 0.0

When a secondary ray is fired, anything within this distance of the intersection point will be ignored. Instead, it is considered part of the current intersection's geometry. If zero, an automatically calculated epsilon will be used.

shadow_ray_epsilon

Float
default: 0.0

When a shadow ray is fired, anything within this distance of the intersection point will be ignored. If this value is less than "ray_epsilon", then it has no additional effect.

Time attributes

evaluation_frame

Float
default: 1.0

Evaluates geometry at the specified frame instead of SceneVariables frame

use_evaluation_frame

Bool
default: False

Uses "evaluation frame" instead of SceneVariables frame

USD attributes

prim_path

String
default:

The geometry Prim to load from the USD Stage

stage

String filename
default:

USD Stage to load

use_master_xform

Bool
default: False

If the prim is an instance proxy, use the xform from the master Prim during geometry creation

use_prim_xform

Bool
default: True

Include the xform from the Prim during geometry creation

use_stage_cache

Bool
default: False

Load the entire stage and use StageCache to share it among all UsdGeometry objects.
If this is false, load a stage masked to the prim path just for this UsdGeometry.
For large stages with thousands of unique assets, it is faster to enable the stage cache

User Data attributes

part_list

StringVector
default: {}

List of part names. The length of the
list should match the length of any "part" rate primitive attribute

primitive_attributes

UserData Vector
default: {}

A list of UserData scene objects specifying arbitrary primitive attributes

Visibility attributes

visible_diffuse_reflection

Bool
default: True

whether the geometry is visible in diffuse reflection

visible_diffuse_transmission

Bool
default: True

whether the geometry is visible in diffuse transmission

visible_glossy_reflection

Bool
default: True

whether the geometry is visible in glossy reflection.

visible_glossy_transmission

Bool
default: True

whether the geometry is visible in glossy transmission (refraction).

visible_in_camera

Bool
default: True

whether the geometry is visible to camera rays

visible_mirror_reflection

Bool
default: True

whether the geometry is visible in miror reflection.

visible_mirror_transmission

Bool
default: True

whether the geometry is visible in miror transmission (refraction).

visible_shadow

Bool
default: True

whether the geometry casts shadows

visible_volume

Bool
default: True

whether the geometry is visible in indirect volume rays

General attributes

contains_camera

Bool
default: False

Specifies whether the geometry contains the camera and should be used for IOR tracking. This should not be changed by the user -- they should instead attach the relevant geometry to the camera, which will then flag this geometry.

curves_subtype

Int enum
  0 = “ray_facing” (default)
  1 = “round”
  2 = “normal_oriented”

Selects the style the curves are rendered

dicing_camera

SceneObject
default: None

Alternate camera that is used for adaptive tessellation. This is useful if you want adaptive tessellation to behave consistently in a sequence, regardless of what the main camera is doing

node_xform

Mat4d blurrable
default: [ [ 1, 0, 0, 0 ], [ 0, 1, 0, 0 ], [ 0, 0, 1, 0 ], [ 0, 0, 0, 1 ] ]

The 4x4 matrix describing the transformation from local space to world space.

references

Geometry Vector
default: {}

list of geometries that geometry procedural can reference during procedural generate/update stages. For example, an instancer geometry procedural can instance primitives generated by the reference geometry procedural.

shadow_exclusion_mappings

String
default:

A space-separated list of mappings of the form A:B where:
A is a comma-separated list of names of parts of this Geometry, or an asterisk to specify the whole geometry;
B is a comma-separated list of shadow receiver set labels established using the ["shadow_receiver_label"] attribute, or an asterisk to specify to all such sets in the scene.
For each of the listed mappings, shadows from the parts specified in A will be suppressed from casting onto any geometries in the ShadowReceiverSets specified in B.
**Note: no part name should appear more than once in the string, otherwise the behavior is undefined.**

static

Bool
default: True

disable if the geometry will be updated between frames

use_explicit_shading_attributes

Bool
default: False

Enable the use of explicit shading attributes (N, dPds, dPdt) if they are present

use_local_camera_motion_blur

Bool
default: False

Enables experimental feature that also attempts to remove the camera blur in the local regions

use_local_motion_blur

Bool
default: False

Enables the local motion blur feature, which makes the geometry procedural responsible for handling all of the geometry's motion and allows for custom effects