Omniverse / Blender Manual

Omniverse’s version of Blender is different from the standard Blender versions. The main benefits of Omniverse’s version are that it includes:

• A variety of USD import and export options

• NVIDIA MDL materials and support

Importing USD Files

To import USD files with Omniverse’s version of Blender, navigate to File > Import > Universal Scene Description:

During import, you can configure what to include:

USD Import

Option	Description
Cameras	Imports camera prims
Curves	Imports curve-based prims
Lights	Imports light prims
Materials	Imports material data
Meshes	Imports mesh data
Blend Shapes	Imports USD blend shapes as shape keys with animation curves. Limitation: Importing blend shape in-betweens is not currently supported.
Volumes	Imports volume data
Skeletons	Imports USD skeletons as armatures with animation curves and creates armature deformers for meshes bound to skeletons. Limitation: USD skeletons with bones that have negative scales cannot currently be imported, as the Blender bone representation does not support such scaling.
USD Shapes	Imports USD Shape primitives as Blender Mesh objects, with animation.
Path Mask	Imports only the subset of the USD scene rooted at the given primitive
Scale	Scales the imported objects with respect to the world’s origin
Apply Unit Conversion Scale	Scales to convert scene units to Blender units (meters)
UV Coordinates	Reads UV coordinates
Color Attributes	Imports color primvars as color attributes
Validate Meshes	Removes non-manifold or otherwise improper geometry from all meshes (slow operation!).
Subdivision	Creates subdivision surface modifiers based on the USD SubdivisionScheme attribute
Import Instance Proxies	Creates unique Blender objects for USD instances
Visible Primitives Only	Ignores invisible USD primitives (This only applies to prims with a non-animated visibility attribute. Prims with animated visibility are always imported.)
Defined Primitives Only	Import only defined primitives. This option can be disabled to allow importing primitive overrides.
Guide	Includes primitives with purpose guide
Proxy	Includes primitives with purpose proxy
Render	Includes primitives with render
Set Frame Range	Updates the Blender scene’s start and end frames to match the incoming USD’s start and end frames
Relative Path	Uses relative paths from the Blender file to the USD file
Create Collection	Adds all imported objects to a collection
Light Intensity Scale	Multiplies light intensity
Convert Light Units from Nits	Converts light intensity values from nits to Blender Light Units
Scale Light Radius	Applies the scene scale factor, from unit conversion or global scaling, to the radius of spot and local lights
Create Background Shader	Imports USD dome lights to world background shaders
Material Name Collision	Determines the behavior when an imported material’s name conflicts with an existing material’s name: Modify: Creates a unique name for the imported material (Default) Skip: Keeps the existing material and discards the imported material
Import Attributes	Determines the behavior when importing USD attributes as Blender custom properties: None: Do not import attributes (Default) User: Import attributes in the userProperties namespace as Blender custom properties. The namespace will be stripped from the property names. All Custom: Import all USD custom attributes as Blender custom properties. Namespaces will be retained in the property names. Supported types are int, float, double, and string. USD vectors are converted to Blender arrays of the corresponding size.
Instancing	Imports USD scenegraph instances as Blender collection instances. (Point instances are not yet handled by this option.)
Import Shaders	Specifies the type of USD shader to convert to Blender Principled BSDF shader networks
Set Material Blend	Sets the material blend method based on the USD shader’s opacity and opacityThreshold settings. (This is based on the Import Shaders type selection.)

Actions

Option	Description
Import USD	Imports the USD file with the options selected
Cancel	Closes the import dialog and cancels the operation

Exporting USD Files

To export USD files in Omniverse’s version of Blender, navigate to File > Export > Universal Scene Description:

During export, you can configure what to include:

Ref #	Link
1	USD Export
2	Attributes
3	Cycles Settings
4	Mesh Options
5	Primitive Types
6	Stage Options
7	Conversion
8	Textures
9	Experimental

USD Export

Option	Description
Use Settings for	Determines the visibility of objects, modifier settings, and other areas where there are different settings for viewport and rendering
Apply Subdiv	Uses subdivision modifiers for mesh evaluation
Author Blender Name	Authors custom userProperties to allow a round trip
Selection Only	Exports only the selected objects (Unselected parents of selected objects are exported as empty transforms.)
Visible Only	Exports only visible objects are exported (Invisible parents of exported objects are exported as empty transforms.)
Animation	Exports the render frame range (If unchecked, only the current frame is exported.)
Export USD Kind	Comning Soon: If a “usdkind” custom string property is on the object, use this to author the matching UsdPrim’s Kind.
Export As Overs	Creates all prims as overrides
Merge Transform and Shape	Merges transforms and shapes into one prim path
Export Identity Transforms	Always authors transform operations, even if the transform is identity/unit/zeroed
Export Child Particles	Exports child particles
Vertex Groups As faceVarying	Exports vertex groups as faceVarying primvars (This uses more disk space and is redundant with Blender’s current authoring tools.)

Attributes

Option	Description
Export Blender Metadata	Exports extra metadata for round-tripping operations, such as original Blender names and the name and path of the original Blender file used for export.
Export Custom Properties	Exports custom properties as USD userProperties: Supported property types are int, float, double, and string Numerical arrays of size two, three, and four are exported as USD vector attributes of the corresponding dimension.)
Add Properties Namespace	Adds exported custom properties to userProperties

Cycles Settings

Option	Description
Override Shutter	Overrides the explicit shutter open and close attributes (When disabled, the shutter is used from Cycles render settings.)

Note

The Blender Cycles Hydra Render Delegate is support in Omniverse Create as a Kit extension. To use the Cycles Hydra Render Delegate, Open Create > Window > Extensions > Cycles Hydra Render Delegate > Click Install

Mesh Options

Option	Description
Vertices	Exports vertex and point data
Vertex Colors	Exports all vertex colors
Vertex Groups	Exports vertex groups
Face Maps	Exports face maps
UV Maps	Exports UV maps of exported meshes
Normals	Includes normals of exported meshes
Triangulate Meshes	Triangulate meshes on export
Method Quads	Methods for how to triangulate quads
Polygons	Methods for how to triangulate NGons

Primitive Types

Option	Description
Transforms	Exports transform data (If disabled, objects will be saved as prims with the identity transform.)
Meshes	Exports mesh data
Materials	Exports material data
Lights	Exports lights
Curves	Exports curve-based shapes
Hair	Exports hair data
Particles	Exports particle data
Armatures	Exports armature data Note: USD requires that skeletons and their skinning target meshes be organized in a hierarchy of “Skeleton Root” (SkelRoot) primitives. Specifically, a skeleton and its target must share a common SkelRoot ancestor to ensure correct binding. Since armatures and meshes with armature modifiers are automatically converted to USD SkelRoots, a straightforward way to maintain a correct hierarchy is to ensure that the target mesh is parented to the armature. Alternatively, there is an experimental “Fix Skel Root” option (in the Experimental section) to automatically find a common Xform ancestor of the skeleton and its target and make that ancestor the SkelRoot. Note that this option could potentially designate the scene root as a SkelRoot, which may be inefficient, especially for large scenes. This can be avoided by grouping the armature and target mesh under an Empty object that isn’t also the scene root. Limitation: Export of “bendy bones” is not currently supported.
Blend Shapes	Exports shape keys as USD blend shapes. Limitations: Export of “absolute” shape keys is not currently supported. In addition, when exporting shape keys, the Blender mesh may not have modifiers applied, other than the armature modifier. Note: USD meshes with blend shape targets are typically bound to skeletons. Thererefore, if exporting armatures is disabled or if the Blender mesh with shape keys doesn’t have an armature deformer, the exported USD mesh will be bound to an automatically created “placeholder” skeleton with a single joint.

Stage Options

Option	Description
Default Prim Path	Specifies the default prim in the USD
Root Prim Path	Adds an Xform prim with the given path as the parent of all prims in the USD scene. Note: The given root path must not match the name of an existing root-level object in the Blender scene. If such a Blender object exists, a warning will be generated and the root prim will not be added. This is avoid redundant names in the path, such as /root/root/.
Material Prim Path	Specifies where all generated USD materials and shaders are placed in the scene
Default Prim Kind	Comning Soon: Specifies the Kind to author on the Default Prim.

Note

We highly recommended users insert a root name (e.g., /root) before all prim paths, as in the default option values. This helps with USD compliance and allows assets sent to Omniverse to work correctly when using sent assets in other scenes:

Conversion

Option	Description
Create ARKit Asset	For USDZ export, flatten the entire stage as per the ARKit Asset recommendations.
Convert Orientation	Converts the orientation axes
Convert to Centimeters	Converts the USD units to centimeters and scales the scene to convert from meters
Export Cycles Shaders	Exports Cycles shader nodes to USD
Convert to USD Preview Surface	Generates an approximate USD preview surface shader network (This is experimental and suitable for converting simple material graphs.)
Convert to MDL	Converts Blender materials to MDL materials (This requires the Universal Material Map (UMM) add-on to be installed.)
Light Intensity Scale	Multiplies light intensity
Convert Light Units to Nits	Converts light intensity values from Blender Light Units to nits
Scale Light Radius	Applies the scene scale factor, from unit conversion or manual scaling, to the radius of spot and sphere lights
Convert World Material	Converts the world material to a USD dome light. (This currently works for simple materials, consisting of an environment texture connected to a background shader, with an optional vector multiply of the texture color.)
Convert uv to st	Renames UV maps to the interchangeable USD primvar name st (If a mesh has multiple UV maps, the active UV map is renamed.)
Xform Ops	Specifies how transform information is represented in USD, using one of the following options: Scale, Rotate, Translate (The rotation is given as XYZ Euler angles.) Scale, Orient, Translate (The rotation is given as a quaternion.) Matrix (The transform is saved as a 4x4 matrix.)

Textures

Option	Description
Export Textures	Exports textures referenced by material nodes to a textures directory in the same directory as the USD. (This assumes materials are being exported.)
Overwrite Textures	Allow overwriting existing files when exporting textures
Relative Texture Paths	Saves material texture asset paths as relative paths in the USD
USDZ Texture Downsampling	For USDZ exports, keep textures the same size, downsample by longest edge to one of the preset sizes, or choose your own custom size

Experimental

Option	Description
Instancing	Exports Blender collection instances as USD scenegraph instances (Particle systems are exported as USD point instances.)
Fix Skel Root	Attempts to automatically correct invalid USD Skeleton Root hierarchies when exporting armatures (Refer to the Armatures option for more information.)

Actions

Option	Description
Export USD	Exports the USD file with the options selected
Cancel	Closes the export dialog and cancels the operation