Export USD data

To open the USD export options, select File > Export> Export.. and select USD (.usd, .usda, .usdc) or USDZ Package (.usdz) under the Files of type drop-down menu. You can also manually type in a file name with .usd, .usda, .usdc or .usdz appended to the name.
Locate your export file folder and click Save.
The following options appear as part of the USD Exporter Dialog. Here you can select what is included when you export a 3ds Max file as a USD scene. Remember: Your USD Exporter settings are remembered only within your current 3ds Max session.
To accept all your changes to the USD Exporter dialog and complete the USD scene export, select Export or choose Cancel to cancel the export operation.

Note:

The USD Exporter has been updated to merge plug-in configuration and user settings for advanced users. Enact custom plug-ins without turning on multiple options in the USD Exporter. For example, USD Preview Surface materials can be written alongside context-driven materials, like Vray Materials (when an appropriate version of Vray is installed). The USD Exporter also utilizes context setting to set necessary chaser and shader settings for plug-ins. Ensure you have the latest plug-ins installed to use this context feature and any applicable plug-in configuration settings.

USD Exporter

Export Path

{Path}: Specifies where to save your USD scene.

Export Definition

Plug-in Configurations: If registered and available, custom chasers can be toggled on from this section. See advanced workflows below for more information.

File

File Name: The output format for your USD export. Available formats are determined by the previously selected extension. When you select File > Export> Export.. choose between USD (.usd, .usda, .usdc) or USDZ Package (.usdz).

For .usd, you can select Binary or ASCII.

Binary (.usdc) is optimized for machine-readability.
ASCII (.usda) is optimized for human-readability.

For .usdz, the export will be an asset package.

USDZ (.usdz) is optimized for asset packaging.

Include

Cameras: When on, cameras are exported. Standard (physical, free and target cameras), 2 types of Vray cameras, and 4 types of Arnold cameras can export directly to USD format.

Note: If attribute values are specified to '0' for the USD file, those attributes will be overwritten as the following: Fstop 8, Shutter 0.5/F, Exposure of EV 6. Cameras with an undefined focus distance attribute get their focus set to 160 F (similar to a Free Camera setting).

Lights: When on, lights are exported. All mappable properties of photometric lights export into USD (including Light intensity, Colors, Direction and Type). There is limited ambient and diffuse multiplier effect support. Photometric SunPositioner exports to USD including sun orientation, mapping color and intensity.

Note: Light instances are not supported with RenderMan render delegate in USDView.

Shapes: When on, shapes are exported. This includes basic curve data extracted to the USD file.

Note: Shapes that do not display in viewport export as UsdGeomBasisCurves and shapes that display in the viewport export as UsdGeomMeshes.

USD Stages: When on, USD stage objects or prims that are found in the 3ds Max scene are exported as USD references to whatever the root layer of that stage object is.

Important: The exported USD references do not reflect the current stage mask if one has been applied to the stage, nor does it contain the animation options for the stage.

USD Stage warnings:

a. The referenced layer has no default prim. In this case, the Exporter uses the first prim found as a reference target.

b. The referenced layer has multiple root prims. In this case, the result might not match expectations, as only a single prim can be targeted in the reference.

c. The layer has in-memory changes (is dirty). In this case, those edits aren't saved and the result may not reflect the current viewport representation.

Geometry: When on, mesh geometry will be exported.

Note: Bone objects (including CAT and Biped) export with the purpose set to guide in USD. This means they do not render, and by default are not shown in USDView. To see them in USDView and verify your export, you need to turn on the display of the Purpose Guide.

Mesh Format: Select the format for output meshes.
- Preserve Existing: Exports meshes as is in the scene.
- Convert to Polygons: Converts meshes to polygonal meshes on export. If meshes are triangulated, polygons are created from invisible edges.
  - Convert to Triangles: Converts all meshes to triangulated meshes on export.
- Preserve Edge Orientation: When on, curved faces in your scene will be split into a collection of planar faces upon export.
- Bake Offset Transform: When on, offset transformations of an object will be baked into their geometry.
- Normals: Select the method for exporting surface normals.
  - As primvar: Exports normals as USD primvars (recommended). Primvars are “primitive variables”, a special attribute associated with a geometric prim (GPrim) to interpolate attribute values over the surface/volume of a prim.
  - As attribute: Exports surface normals as attributes.
  - None: Surface normals are not exported.
- Vertex Channels: Select the level of export for vertex channels. Choose between All, None and Custom. If you choose Custom, select the gear icon to configure the following in your channel export:
- Export: Select to include in export.
- Channel: Specifies the map channel ID.
- Target Primvar: Type in the specific primvar to target. Primvar name can only contain alphanumeric characters, underscores, and the field cannot be empty.
  
  Note: USD Map channel names default to st0, st1, st2. in the USD Exporter to align more closely with the names used in other applications (such as Maya). This enables ease of material library reuse across applications. If you are an advanced user, you can customize the naming translations using scripting.
- Primvar Type: Specifies the type of primvar for the channel.

Hidden Objects: When on, hidden objects are included in your USD export.

Use USD Visibility: When on, export marks hidden objects as USD invisible.

Important: visibility discrepancies can occur with this setting (meaning hidden ascendant nodes with visible descendent can result in hidden nodes due to the USD inheritance schema).

Materials

Export Materials: When on, shading data will be exported. Note: A basic material is always exported, even when the material is not understood during material translation(name and diffuse color is written out to the export). If available, custom shaders can also appear in this section. See advanced workflows below for more information.

MaterialX: Exports bound materials as part of the MaterialX USD Shade network.
USD Preview Surface: When on, all supported materials are converted to UsdPreviewSurface shaders on export. Supported 3ds Max materials are USD Preview Surface and Physical Material.

Note: This materials list can grow and provide more options depending on available plug-in additions, custom shader and chaser networks. See Advanced Workflows below to learn more.

Best Practices
For best results and to avoid material conversion, prior to USD export, use the Material Map Browser in 3ds Max to set materials to UsdPreviewSurface by selecting Materials > USD > Usd Preview Surface.

Important: Not all parameters map to UsdPreviewSurface directly. For example, UsdPreviewSurface does not support both "cutout" and "transparency" (it supports one or the other).

Related Concepts: See UsdPreviewSurface in the Pixar USD documentation.

Animation

Deformers

Skin: When on, the export encodes skin and skeletons as USDSkel. Skinned meshes export as USDSkel instead of animated vertex caches.

Morph Targets: When on, exports morph targets as USD blend shapes. Animations using morph targets thus get exported as USD blend shapes and the animation will appear when viewing the exported file in USDView.

Warning: Morph targets export with USD blendshapes, but skinning information may not properly display in USDView. See Limitations for more information and a workaround.

Time Range

Select the time at which animation data is exported from your scene. You can select a frame range to export to USD and the animations will be cached into USD. Choose from the following options:

Animation Range: Exports animation data from the active timeline. Select this option if you want to use your current Animation Range in the Time Slider.
Current Frame: Exports animation data from the active frame.
Frame Number: Exports animation data from the specified frame.
Frame Range: Exports animation data from the specified start and end frames.

Note: Choose Frame Range or Animation Range to specify a range of animation frames to export, extracted at a sample/ frame value (note that sample/frame value is limited to 0.01-100).

Animation Export Support

The following is supported in the export of animations:

Vertex animations
Splines with Animation data (transform manipulation and point modification are both supported)
Node Transforms

General Settings

Up Axis: Select the upward axis of orientation for your USD scene. Default is Z-up.

Advanced

Log File: When on, a log file is output with your render. By default, log data is not stored.

Output: Select the type of log data to be stored from exporting your scene. Choose from Errors Only, Errors and Warnings or Full Log Data.
Log Path: Specify where to save log data. Select the ellipses to navigate to a directory.

Allow Nested Gprims: When on, the export allows for nested geometric prims (GPrims). This can maintain existing hierarchy and help performance by reducing prim counts.

Warning: This is not strictly valid in USD and warnings will be issued in USDView and any DCCs.

View Results in USDView: When on, the USD file opens in USDView following the export.

Note: For USDView to open, your machine must have python.exe and a graphics card. USDView loads the scene exported to both local and network drives.

Advanced Scripting Workflows using the 3ds Max SDK

The 3ds Max USD SDK allows 3rd-party developers to extend the USD Exporter and customize/ enhance available export options. Plug-in developers can write custom USD prim writers, shaders and chasers enabling additonal extensibility to the USD Exporter. To learn more, the SDK is available in a separate download from the Autodesk developer network. For other scripting information, see the MaxScript USD Documentation.