User Manual

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

Note

The following sections on importing and exporting USD files from the main File menu apply to reading and writing assets on the local file system (or on a virtual file system, such as Omniverse Drive). To access assets directly on the Omniverse servers, please use the Import USD and Export USD options provided by the Nucleus Connector add-on.

Importing USD Files

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

Numbered instructions for importing USD from file menu

During import, you can configure what to include:

Menu for importing USD files

Ref #

Link

1

General

2

Import Types

3

Geometry

4

Materials

5

Textures

6

Lights

7

Rigging

8

Animation

9

Particles and Instancing

General

Option

Description

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.

Create Collection

Adds all imported objects to a collection

Relative Path

Uses relative paths from the Blender file to the USD file

Apply Unit Conversion Scale

Scales to convert scene units to Blender units (meters)

Scale

Scales the imported objects with respect to the world’s origin

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.

Import Types

Option

Description

Meshes

Imports mesh data

Curves

Imports curve-based shapes

Volumes

Imports volume objects

USD Shapes

Imports USD Shapes as Meshes

Cameras

Imports cameras

Lights

Imports lights

Materials

Imports material data

Geometry

Option

Description

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

Materials

Option

Description

Import All Materials

If enabled, imports materials in the USD file even if they’re not assigned to imported geometry.

Color Attributes

Imports color primvars as color attributes

Validate Meshes

Removes non-manifold or otherwise improper geometry from all meshes (slow operation!).

Import Subdivision Scheme

Creates subdivision surface modifiers based on the USD SubdivisionScheme attribute

Textures

Option

Description

Import Textures

Where to import textures. Packed loads the textures as Images in the current Blender file. Copy will copy the files to a local folder. None will stop textures from being imported.

Textures Directory

If you choose to import textures through a Copy, this is the folder to which the textures will be written. If the path starts with //, then the textures will be written relative to the Blender file on disk.

File Name Collision

If overwrite is chosen, textures on disk will be overwritten if they exist. If use existing is chosen, then textures on disk will not be overwritten and instead will be reused.

Lights

Option

Description

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

Light Intensity Scale

Multiplies light intensity

Rigging

Option

Description

Import Armatures

Import USDSkel as Blender Armatures

Blend Shapes

Import USDSkel Blend Shapes as Blender Shape Keys

Animation

Option

Description

Set Frame Range

If enabled, match the current Blender Scene’s start and end frames to those in the USD file

Particles and Instancing

Option

Description

Scene Instancing

Import USD scene graph instances as Collection Instances. If disabled, such instances will be imported as unique objects

Note: This option does not apply to USD point instancers which are always imported as point clouds with point instancing geometry nodes

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:

Numbered instructions for exporting USD from file menu

During export, you can configure what to include:

Numbered menu for exporting USD files

Ref #

Link

1

General

2

Stage

3

Export Types

4

Geometry

5

Materials

6

Lights

7

Rigging

8

Animation

9

Particles and Instancing

General

Option

Description

Use Settings for

Determines the visibility of objects, modifier settings, and other areas where there are different settings for viewport and rendering

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.)

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

Relative Paths

Export paths referenced by the USD file as relative to that file.

Export As Overs

Creates all prims as overrides

Merge Transform and Shape

Merges transforms and shapes into one prim path

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.)

Stage

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

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:

Blender export menu for stage options

Export 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

Cameras

Exports cameras

Curves

Exports curve-based shapes

Geometry

Option

Description

Apply Subdiv

Uses subdivision modifiers for mesh evaluation

Vertex Colors

Exports all vertex colors

Normals

Includes normals of exported meshes

UV Maps

Exports UV maps of exported meshes

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.)

Triangulate Meshes

Triangulate meshes on export

Materials

Option

Description

Convert to USD Preview Surface

Generates an approximate USD preview surface shader network (This is experimental and suitable for converting simple material graphs.)

Export Cycles Shaders

Exports Cycles shader nodes to USD

Convert to MDL

Converts Blender materials to MDL materials (This requires the Universal Material Map (UMM) add-on to be installed.)

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.)

Use Original Paths

Use the original USD asset path for textures that were previously imported (e.g., textures that were downloaded to the local file system from Omniverse URIs). This option is not available when exporting textures

Overwrite Textures

Allow overwriting existing files when exporting textures

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

Lights

Option

Description

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.)

Rigging

Option

Description

Armatures

Exports armatures as skeletons and meshes with armature modifiers as skinned meshes.

Limitation: Export of “bendy bones” is not currently supported.

Export Shape Keys

Exports shape keys as USD blend shapes.

Limitations: Export of “absolute” shape keys is not currently supported.

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 modifier, the exported USD mesh will be bound to an automatically created “placeholder” skeleton with a single joint.

Only Deform Bones

Only export deform bones and their parents

Note

When the “Armatures” or “Export Shape Keys” options are enabled and a mesh has an armature modifier or shape keys, the pre-modified mesh will be exported for skinning in USD. This means that the exported skinned mesh will not have any modifiers applied, other than the armature modifier. Therefore, it may be necessary to apply modifiers (e.g., mirror or subdivision modifiers) to the mesh prior to export to get the expected results.

Note

USD requires that skeletons and their skinning target meshes be exported under a “Skeleton Root” (SkelRoot) primitive in the USD hierarchy. Specifically, a skeleton and its target must share a common SkelRoot ancestor to ensure correct binding. To help ensure that the correct SkelRoot hierarchy is maintained, the USD exporter will automatically find a common Xform ancestor of the skeleton and its target and make that ancestor the SkelRoot.

Animation

Enabling the checkbox in the header of the Animation panel will enable exporting of time-sampled animation. If this is not enabled, a USD file that mirrors the state of the scene at the current frame will be exported.

Option

Description

Start

Start frame to export

End

End frame to export

Frame Step

How often to sample. A value of 1.0 means the exporter will sample once every frame.

Particles and Instancing

Option

Description

Export Particles

Exports Blender particles

Export Hair as Curves

Export Blender Hair Objects as Curves

Export Child Particles

If enabled, all particles in a particle system or particle hair will be exported. If disabled, only parent particles / hairs will be exported.

Export as Instances

Exports Blender collection instances as USD scenegraph instances (Particle systems are exported as USD point instances.)

Actions

Option

Description

Export USD

Exports the USD file with the options selected

Cancel

Closes the export dialog and cancels the operation