Release Notes

Materials - Release Notes - 2022.3.0

Material improvements


UsdPreviewSurface now supports unitless emissive texture map values. Previously, the RTX and Iray renderers assumed that map values were in Nits. Emissive units is not specified in the USD specification and in HdStorm and other renderers, the textured value is often the final exposed RGB value in the image.

In 2022.3.0 emissive values are scaled such that their value is equal to the output RGB image for our default camera Exposure

Camera Exposure







Distant Light

UsdPreviewSurface supports UsdTransform2d and UsdPrimvarReader nodes

MDL Reloading

Omniverse will now dynamically re-load changes to MDL source, updating the MDL database and re-compile the material.


Omniverse adds the base OmniPBR template model to the Material Editor. You can now map and modify inputs directly to the base material model to create custom MDL materials.

Material Editor

Authors can now add their own materials and functions to the Material Editor Node List.

MaterialX Read supports

Omniverse supports reading of .mtlx material documents.

MDL Path Resolution Changes

Summary of the changes for resolving MDL paths:

  • MDL built-in paths (i.e OmniPBR.mdl, OmniPBR_ClearCoat.mdl, OmniSurface, nvidia/aux_definitions.mdl, nvidia/core_definitions.mdl, OmniUE4Base.mdl, etc.) will no longer be anchored to their referencing layer URL (i.e omniverse://nucleus-server/some/stage.usd or https://server/some/other/stage.usd). These MDL built-in paths will still resolve correctly if they live next to the referencing layer URL but that is completely handled by the client-library and not USD

  • MDL paths not prefixed with “./” or “../” can still be anchored relative to the referencing layer if they exist and the referencing layer is a URL or file path on disk

  • MDL built-in paths are no longer considered search paths

  • MDL built-in paths are no longer considered relative paths unless prefixed with “./” or “../”

  • This behavior works through SdfAssetPath type Attributes without modifying Sdf

  • This behavior can be enabled / disabled by setting the environment variable OMNI_USD_RESOLVER_MDL_BUILTIN_BYPASS or in <APPLICATION>/kit/extscore/omni.usd.config/omni/usd_config/

  • At the moment, this resolve behavior is disabled by default by can be easily switched

Omniverse RTX Renderer - Release Notes - Kit 104.2




  • Can now load up to 8.7 million instances

  • Render Time is now included in EXIF metadata

  • Emit warning when incompatible texture assigned to material parameter


  • Fixed various crashes and instability issues

  • Fixed ‘16k square, 16 bit RGB textures cannot be loaded’

  • Fixed ‘UsdGeomMesh display color flickering on deformed mesh’

Known issues

  • When curve type is set to linear and wrap mode is pinned, curve disappears.

RTX - Real-Time


  • Added ‘Mesh-Light Sampling’ to Render Settings under Direct Lighting, available when Sampled Direct Lighting Mode is enabled: Enables direct illumination sampling of geometry with emissive materials.

Known issues

  • Glitch can occur causing smearing, sometimes red or blue or yellow-colored. Work-around is to change ‘NVIDIA DLSS Super Resolution’ to DLAA and back to DLSS or vice-versa, under Render Settings/Real-Time/NVIDIA DLSS.

RTX – Interactive (Path Tracing)


  • Added ‘Mesh-Light Sampling’ to Render Settings under Sampling & Caching: Enables direct illumination sampling of geometry with emissive materials.


  • Fixed various bugs with Light-Linking

  • Fixed ‘Adaptive Sampling breaks Multi Matte rendering’

Post Processing

Known issues

  • Matte Object: ‘Output Alpha in Composited Image’ breaks if the mesh is set to Invisible in Secondary Rays

Omniverse RTX Renderer - Release Notes - Kit 104.1



  • Added ‘Visible in Primary Ray” setting to Distant Light

  • Implemented the camera projection type ‘fisheyeKannalaBrandtK3’ model

  • The default cyan placeholder color is now user configurable. Added a ‘Placeholder Texture Color’ under Preferences/Rendering/Texture Streaming


  • Can now render many thousands of lights for a minimal GPU memory cost compared to previous releases.

  • Faster update for large number of meshes

  • Added indication of which GPUs are active to the viewport GPU HUD info

  • Changed texture streaming behavior so that now if a mip size is larger than Texture Streaming “Budget Per Request” it will not prevent the mip from being loaded


  • Fixed ‘Geometry corruption in time-sampled subdivision surfaces when animated’

  • Fixed performance regression for animated Dome Light with materials

  • Fixed various crashes and instability issues

  • Fixed GPU normals generation to not smooth across edges that were intended to be sharp or vice-versa

  • Fixed ‘Viewport corruption, “Out of resource descriptors” error after leaving an app running for a few hours’

  • Fixed ‘Instance prims have no outlines when they are selected’

  • Fixed ‘Varying displayColor primvar is missing, gets discarded and won’t update during playback’

Known issues

  • Loading more than around 5m becomes unstable

  • 16k square, 16 bit RGB textures cannot be loaded

RTX - Real-Time


  • Handle thousands of lights efficiently (saves around 50% of previous memory usage with 8k+ lights)

  • Improved rendering of colored metals for OmniSurface in real-time, now a closer match to Path Tracing

  • Track self occlusion at the mesh instance level for SDG


  • Various fixes for ‘Material Distilling (Experimental)’, which can be enabled in Preferences/Rendering/MDL

  • Fixed ‘Simple Fog looks incorrect if New Denoiser + Sampled Direct Lighting is enabled’

  • Fixed ‘If XR Compositing or Matte Object is enabled, background clips translucent materials’

  • Fixed ‘Fisheye Spherical Projection Type has camera visible on the sides, or appears black’

  • Fixed ‘When exporting .exr images the tone-mapper is internally flipped to linear scale’

Known issues

  • Glitch can occur causing smearing, sometimes red or blue or yellow-colored. Work-around is to toggle some render settings once, for example changing ‘NVIDIA DLSS Super Resolution’ to DLAA and back to DLSS, under Render Settings/Real-Time.

RTX – Interactive (Path Tracing)


  • Added ‘Automatic Load Balancing’ to MGPU render settings, true by default

  • Added AOV setting to output ‘32-bit depth AOV’


  • Improved the Adaptive Sampling global error computation.


  • Fixed ‘At low sample count, matte objects render black, until more samples have accumulated

  • Fixed ‘Matte object: global volumetrics (fog) does not work with matte object’

  • Fixed ‘excluding objects using a Dome light breaks light linking’

Post Processing


  • Alpha is now calculated for every pixel with zero alpha based on luminance


  • Fixed ‘FFT Bloom: Physical/Non-Physical combo box selection VS shown settings is inverted’, now a bool again

Omniverse RTX Renderer - Release Notes - Kit 104.0



  • Added settings to ‘Common/Geometry/Curves Settings’ and to ‘Basis Curves’ to control the Number of BVH Splits used in curves’ ray acceleration structure, which provides improved balancing capabilities of performance and memory usage by curves.

  • Added profiling Heat Map views to ‘Common/Debug View’ which are used to visualize frame time spent per pixel, or the number of invoked Intersection shaders or Any Hit shaders per pixel.

  • Added an ‘Invisible Lights Roughness Threshold’ setting to ‘Common/Lighting/Light Visibility Settings’, which defines the surface roughness treshold below which lights invisible in primary rays are also invisible in reflections and refractions.

  • Added a ‘Projector Light Type’ setting to ‘Rect Light’, which enables focusing a textured light like a projector. Scale the light as desired to adjust the focus area.

  • Added .tiff image format support.

  • Refactored ‘Lighting Mode’ settings for Dome Lights in ‘Common/Lighting/Dome Light Settings’, which now provide ‘Image-Based Lighting’ (simply a rename of the previous default, highest quality but can introduce artefacts in Real-Time) and ‘Limited Image-Based Lighting’ (fastest and few if any artefacts in Real-Time, but only affects reflection and refraction).


  • Creation time and update time for mesh geometry has been significantly improved, very dense meshes can now load up to 3x faster.

  • Geometry loading is now asynchronous with priority given to large-sized geometry (e.g., walls would be loaded before rivets). Loading is suspended when running out of memory, giving the user an opportunity to work with scenes that otherwise would not fit in memory.

  • Now honiring the ‘Normalize’ flag in UsdLight for area lights.

  • Various performance and memory optimizations.

  • Added tooltips for all render settings.


  • Various tangent/normal computation fixes including when geometry is animated.

  • Various Multi-GPU stability improvements and bug fixes.

  • Fixed ‘Picking is returning random prim paths when selecting in Prim mode.’

  • Fixed ‘Procedural AABB is sometimes incorrectly drawn in DirectX.’

  • Fixed ‘Multi-GPU picking and querying is failing with multiple Viewports open.’

  • Fixed ‘Simple Fog is still visible even if Intensity is set to 0.’

  • Fixed ‘Discontinuity along curves or hair fibers when the endcaps option set to open.’

  • Fixed ‘Setting the wrap mode to black for UDIM texture sequences results in incorrect texture lookups.’

  • Fixed ‘Changing resolution to 2048x1080 can cause BSOD or flickering.’

Known issues

  • Loading around 5m instances crashes.

  • 16k square, 16 bit RGB textures cannot be loaded.

  • DistantLight has no “Visible in primary rays” checkbox, unlike other light types.

RTX - Real-Time


  • Added ‘Frame Generation’ setting to ‘Real-Time/NVIDIA DLSS’: uses AI to boost frame rates by generating additional high-quality frames in real-time. This feature requires an Ada Lovelace architecture GPU. Windows version must be equal or greater than 20H1. Not yet supported on Vulkan or Linux.

  • Added ‘New Denoiser (experimental)’ setting to ‘Real-Time/Direct Lighting’ which can reduce ghosting or noise in some contexts.

  • Added ‘Distilling (experimental)’ setting in ‘Preferences/Rendering/MDL’: Enables transforming MDL materials of arbitrary complexity to predefined target material models, which can improve material rendering fidelity in RTX Real-Time mode, such as for complex materials like Clear Coat.


  • Improved rendering fidelity of real-time SSS when Sampled Direct Lighting is enabled.


  • Fixed various SSS bugs

  • Fixed ‘Dome Light results in outline visible on reflective surfaces when Sampled Direct Lighting is not enabled.’

  • Fixed ‘Real-time global volumetrics has a lot of large-scale noise if Sampled Direct Lighting is not enabled.’

  • Fixed ‘Reflections in glass appear jagged, shimmer.’

Known issues

  • Distilling (experimental): Colorful noise pattern sometimes appears where the surface is reflective while Distilling is enabled.

  • Distilling (experimental): The translucency appears dark in some cases while Distilling is enabled, including on particles.

  • Distilling (experimental): Detail normal maps are not visible.

  • New Denoiser (experimental): Simple Fog is incorrectly rendered if Sampled Direct Lighting is also enabled while New Denoiser is enabled.

  • New Denoiser (experimental): Translucent materials can appear blurry when in motion while New Denoiser is enabled.

  • New Denoiser (experimental): Pronounced noise behind translucent materials may appear magnified by refraction while New Denoiser is enabled.

  • New Denoiser (experimental): Points in motion are very blurry while New Denoiser is enabled.

  • If XR Compositing or Matte Object is enabled, translucent materials may appear clipped by the background.

  • glTF material appears black.

  • Dark bands are visible on sky mesh when both “Global Volumetric Effects” and Translucency “Fractional Cutout Opacity” are enabled.

  • Textures are not supported in Rect Lights unless Sampled Direct Lighting is enabled (although is supported if Projector Light Type = true).

  • Dark line appears around the edge of the viewport at resolutions of 720 or less if Sampled Direct Lighting or New Denoiser is not enabled.

RTX – Interactive (Path Tracing)


  • Added ‘Multi Matte’ settings in ‘Interactive (Path Tracing)’ which extends AOV support by enabling rendering masked mesh geometry to AOVs, providing additional opportunities to modify the final image during compositing and additional insights through 2D analysis.

  • Added ‘Adaptive Sampling’ settings in ‘Interactive (Path Tracing)/Path-Tracing’ which limits the number of additional samples to render for a pixel based on a user defined noise threshold. The samples are non-uniformly distributed over the image resulting in less noise for the same number of samples and also provides a more consistent noise level across multiple frames.

  • Added ‘Denoise AOVs’ setting in ‘Interactive (Path Tracing)/Denoising’ to apply the Optix Denoiser to AOVs.


  • Fixed ‘Global volumetrics (fog) causes surfaces to look transparent when rendering Matte Objects.’

  • Fixed ‘If Matte Object is enabled, Depth of Field will not work against the background.’

  • Fixed ‘A few of the AOV passes do not have a checkbox to enable them for preview.’

Known issues

  • Multi Matte: Mesh geometry Multi Matte ID -1 is treated as 0.

  • Multi Matte: Changing the Multi Matte settings does not force a reset the frame.

  • UI responsiveness can lag when rendering complex volumes.

  • At low sample count, matte objects render black, until more samples have accumulated.

Post Processing


  • Added ‘Dither Strength’ setting in ‘Post Processing/Tone Mapper’ to reduce banding when rendering smooth gradients.

RTX – Accurate (Iray) - Release Notes - Kit 104.0


  • Added ‘Guided Sampling’ setting in ‘Accurate (Iray)/Render Settings’: Enabling this option will usually help convergence speed of interior or other complicated scenes at the price of slightly increased rendering times per iteration and higher memory usage. Thus, simple scenes such as turntable-like objects will not profit, and may even render a bit slower.

  • Added ‘Backplate Refraction’ settings in ‘Accurate (Iray)/Render Settings’: Forces perfectly specular, non-thin walled materials to respect the virtual backplate. Note that this can lead to visible discontinuities on complex geometric shapes due to the mixture of both the backplate (texture and color) and environment dome contributions.

  • Added ‘Iray Server’ settings in ‘Accurate (Iray)’: Iray can connect to an Iray Server running on a different machine. Iray server is a stand alone application connecting via a network. More info here:

  • Added ‘Environment Sample Count’ setting in ‘Accurate (Iray)/Advanced’: Increase this to get a higher quality when baking the dome light.

  • Added ‘Window Glass Optimization’ setting in ‘Accurate (Iray)/Advanced’: Check this if you need faster rendering in cases where light is travelling through e.g. flat window panes.

  • Added ‘Use Iray’s Built-In Denoiser’ setting in ‘Accurate (Iray)/Advanced’: Check this if you want to use Iray’s internal denoiser (recommended for an Iray Server connection).

  • Added ‘Temporal Denoising During Navigation’ setting in ‘Accurate (Iray)/Advanced’: The Temporal Denoiser is used during Navigation.


  • Fixed ‘Iray won’t write a correct HDR EXR frame (capped at 1.0).’

  • Fixed ‘Iray sometimes crashes when rendering dense hair curves.’

Known issues

  • Light and camera icons / manipulators and Grid are not showing in Iray

  • Some settings in Common render settings are not supported in Iray