Path Tracing#
Path Tracing mode uses progressive sampling to converge towards
ground-truth-quality images. In ovrtx, a render step accumulates towards the
omni:rtx:pt:samplesPerPixel limit before returning output, so application
code usually captures Path Tracing output with a single step rather than the
multi-frame warm-up loop used for Real-Time Path-Tracing convergence. Path Tracing is best suited
for offline or reference-quality workflows where convergence time is acceptable.
token omni:rtx:rendermode = "PathTracing"
Warm-Up#
PathTracing mode does not need the same warm-up loop for path-tracing convergence that Real-Time Path-Tracing uses. Texture availability can still matter if an application requires high-resolution mips in the first captured frame.
Settings#
Path Tracing#
USD declaration |
Description |
|---|---|
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Maximum number of samples to accumulate per pixel. When this count is reached, rendering stops until a scene or setting change is detected. Set to 0 to remove this limit. |
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Number of samples per pixel, per iteration. Multiple iterations can be run per launch to reduce kernel launch overhead. |
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When enabled, noise values are computed for each pixel, and upon reaching the threshold level the pixel is no longer sampled. |
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Maximum number of ray bounces for any ray type. Higher values give more accurate results, but worse performance. |
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Maximum number of ray bounces for specular and transmission. |
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Maximum number of ray bounces for SSS. |
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Maximum number of bounces for volume scattering within a fog/sky volume. |
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If disabled, material opacity is considered binary: values greater than or equal to 0.5 are considered opaque, while values less than 0.5 are considered transparent. |
Denoising#
USD declaration |
Description |
|---|---|
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Runs the selected denoiser on the image. |
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Uses motion information to reduce frame-to-frame flickering artifacts in the denoiser. |
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Blend factor indicating how much to blend the denoised image with the original. 0 shows only the denoised image, 1.0 shows no denoising. |
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If enabled, the OptiX Denoiser also denoises additional render variables alongside the color output. |
Sampling and Caching#
USD declaration |
Description |
|---|---|
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Enables caching path-tracing results for improved performance at the cost of some accuracy. |
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Enables the many-light sampling algorithm, which can improve performance in scenes with many lights. |
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Enables direct illumination sampling of geometry with emissive materials. |
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Enables caching lighting results for improving surface ray sampling directions. |
Firefly Filter#
USD declaration |
Description |
|---|---|
|
Enables the firefly filter. |
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Clamps the maximum ray intensity for glossy bounces. Can help prevent fireflies, but can result in energy loss. Automatically scaled with exposure. |
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Clamps the maximum ray intensity for diffuse bounces. Can help prevent fireflies, but can result in energy loss. Automatically scaled with exposure. |
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Clamps the maximum ray intensity for emissive contribution after primary bounce. Can help prevent fireflies, but can result in energy loss. Automatically scaled with exposure. |
Spectral Rendering#
See Spectral Rendering for startup configuration, physical illuminants, and RGB-versus-spectral comparisons.
USD declaration |
Description |
|---|---|
|
Enables spectral rendering. |
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Minimum simulated wavelength in nanometers. |
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Maximum simulated wavelength in nanometers. |
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Color space input is converted from and to spectral. |
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Response curve to convert spectral to CIE XYZ. |
Non-Uniform Volumes#
USD declaration |
Description |
|---|---|
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Enables path-traced non-uniform volumes. |
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Choose between |
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Maximum delta tracking steps between bounces. Increase for highly scattering volumes like clouds. |
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Maximum ratio tracking delta steps for shadow rays. Increase for highly scattering volumes like clouds. |
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Maximum number of bounces in non-uniform volumes. |
Multi-GPU#
USD declaration |
Description |
|---|---|
|
Enables rendering across multiple GPUs when available. |
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Automatically balance path-tracing work across GPUs in a multi-GPU configuration. |
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Enables lossy compression of per-pixel output radiance values. |
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Enables lossy compression of per-pixel output albedo values (needed by OptiX denoiser). |
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Enables lossy compression of per-pixel output normal values (needed by OptiX denoiser). |
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Enabling multi-threading improves UI responsiveness. |
Global Volumetric Effects#
USD declaration |
Description |
|---|---|
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Enables an additional medium of Rayleigh-scattering particles to simulate a physically based sky. |
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Scales the size of the Rayleigh sky. |
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If a domelight is rendered for the sky color, the Rayleigh atmosphere is applied to the foreground while the background sky color is left unaffected. |
Anti-Aliasing#
USD declaration |
Description |
|---|---|
|
Sampling pattern used for anti-aliasing. Select from |
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Sampling footprint radius, in pixels, when generating samples with the selected anti-aliasing pattern. |