Configuring RTX Rendering Settings

Note

This guide covers the RTX renderer settings, which are used when running Isaac Lab with Isaac Sim. The RTX renderer is based on NVIDIA’s Omniverse RTX rendering pipeline and is available for all camera sensors in the PhysX backend.

For the Newton renderer (used with the Newton backend or in kit-less mode), see Renderers for the pluggable renderer architecture and available backends.

Isaac Lab’s RTX renderer applies high-fidelity camera rendering defaults when running with --enable_cameras. Override individual settings to tune the renderer for your workflow, as described below. For camera-heavy workloads that need higher throughput, switch to the RTX Minimal renderer instead.

Overriding Specific Rendering Settings

RTX rendering settings can be overridden via IsaacRtxRendererGlobalSettingsCfg.

There are 2 ways to provide settings that override the defaults.

1. IsaacRtxRendererGlobalSettingsCfg supports overriding specific settings via user-friendly setting names that map to underlying RTX settings. For example:

   global_settings = IsaacRtxRendererGlobalSettingsCfg(
      # user-friendly setting overrides
      enable_translucency=True,  # render glass / transmissive surfaces
      enable_reflections=True,  # render reflections
      dlss_mode=3,  # 0 (Performance), 1 (Balanced), 2 (Quality, the default), 3 (Auto)
   )
   

   List of user-friendly settings.

   enable_translucency	Bool. Enables translucency for specular transmissive surfaces such as glass at the cost of some performance.
   enable_reflections	Bool. Enables reflections at the cost of some performance.
   enable_global_illumination	Bool. Enables Diffused Global Illumination at the cost of some performance.
   antialiasing_mode	Literal[“Off”, “FXAA”, “DLSS”, “TAA”, “DLAA”]. DLSS: Boosts performance by using AI to output higher resolution frames from a lower resolution input. DLSS samples multiple lower resolution images and uses motion data and feedback from prior frames to reconstruct native quality images. DLAA: Provides higher image quality with an AI-based anti-aliasing technique. DLAA uses the same Super Resolution technology developed for DLSS, reconstructing a native resolution image to maximize image quality.
   enable_dlssg	Bool. Enables the use of DLSS-G. DLSS Frame Generation boosts performance by using AI to generate more frames. This feature requires an Ada Lovelace architecture GPU and can hurt performance due to additional thread-related activities.
   enable_dl_denoiser	Bool. Enables the use of a DL denoiser, which improves the quality of renders at the cost of performance.
   dlss_mode	Literal[0, 1, 2, 3]. For DLSS anti-aliasing, selects the performance/ quality tradeoff mode. Valid values are 0 (Performance), 1 (Balanced), 2 (Quality), or 3 (Auto).
   enable_direct_lighting	Bool. Enable direct light contributions from lights.
   samples_per_pixel	Int. Defines the Direct Lighting samples per pixel. Higher values increase the direct lighting quality at the cost of performance.
   enable_shadows	Bool. Enables shadows at the cost of performance. When disabled, lights will not cast shadows.
   enable_ambient_occlusion	Bool. Enables ambient occlusion at the cost of some performance.

2. For more control, IsaacRtxRendererGlobalSettingsCfg allows you to override any RTX setting by using the carb_settings argument.

   The full NVIDIA RTX renderer documentation can be found at https://docs.omniverse.nvidia.com/materials-and-rendering/latest/rtx-renderer.html.

   An example usage of carb_settings.

   global_settings = IsaacRtxRendererGlobalSettingsCfg(
      # raw carb setting overrides
      carb_settings={
         "rtx.translucency.enabled": False,
         "rtx.reflections.enabled": False,
         "rtx.domeLight.upperLowerStrategy": 3,
      }
   )
   

Current Limitations

For performance reasons, we default to using DLSS for denoising, which generally provides better performance. This may result in renders of lower quality, which may be especially evident at lower resolutions. Due to this, we recommend using per-tile or per-camera resolution of at least 100 x 100. For renders at lower resolutions, we advice setting the antialiasing_mode attribute in IsaacRtxRendererGlobalSettingsCfg to DLAA, and also potentially enabling enable_dl_denoiser. Both of these settings should help improve render quality, but also comes at a cost of performance. Additional rendering parameters can also be specified in IsaacRtxRendererGlobalSettingsCfg.

If you observe visual artifacts such as ghosting or disocclusion issues when using tiled rendering, you can try adjusting the disocclusionScale parameter. This setting controls how aggressively the renderer handles areas that become newly visible between frames:

global_settings = IsaacRtxRendererGlobalSettingsCfg(
   carb_settings={
      "/rtx/aovConverter/disocclusionScale": 10000,
   }
)

Note

This parameter is not commonly exposed as it may have side effects in certain scenarios. Only use it as a last resort if other quality settings do not resolve the visual artifacts. The value can be adjusted to a very high value to reduce disocclusion artifacts.

Rendering UsdVol 3D Gaussian Scenes in Multiple Environments

When using UsdVol volumes with 3D Gaussian particles (e.g. exported from 3DGRUT) in multiple environments, you must set the following so the renderer uses the correct compositing path:

global_settings = IsaacRtxRendererGlobalSettingsCfg(
   carb_settings={
      "omni.rtx.nre.compositing.rendererHints": 3,
   }
)

Warning

With multiple environments, each environment holds its own copy of the scene, increasing device memory use, and environments are rendered one after another, which can substantially slow down rendering.