RTX Interactive (Path Tracing) Settings¶
Anti-Aliasing¶
Setting |
Effect |
|---|---|
Anti-Aliasing Sample Pattern |
Sampling pattern used for the purposes of Anti-Aliasing. Select between Box, Triangle, Gaussian and Uniform.
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Anti-Aliasing Radius |
Radius, in pixels, of the sampling footprint to use when generating samples with the selected antialiasing sample pattern.
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Firefly Filtering¶
Setting |
Effect |
|---|---|
Firefly Filtering |
Enables logic to reduce the occurrence of “firefly” artifacts.
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Max Ray Intensity Glossy |
The maximum light intensity (in radiance units) that can be contributed along any one ray for glossy events (when the firefly filter is enabled).
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Max Ray Intensity Diffuse |
The maximum light intensity (in radiance units) that can be contributed along any one ray for diffuse events (when the firefly filter is enabled).
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Path-Tracing¶
Setting |
Effect |
|---|---|
Max Bounces |
Maximum number of bounces in a path.
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Max Specular and Transmission Bounces |
Maximum number of bounces for specular and transmission events.
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Max SSS Volume Scattering Bounces |
Maximum number of bounces for subsurface scattering within a volume.
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Max Fog Scattering Bounces |
Maximum number of bounces for volume scattering within a fog volume.
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Max Non-Uniform Volume Scattering Bounces |
Maximum number of bounces for non-uniform volumes.
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Dome Lights: High Quality Primary Rays |
Can improve sampling quality of dome lights with an MDL material assigned, at the cost of performance.
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Samples per Pixel per Frame (1 to 32) |
Total number of samples used for each rendered pixel in one frame update.
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Total Samples per Pixel (0 = inf) |
Maximum number of samples to accumulate per pixel. When this sample count is reached the rendering stops and the same image is displayed until a scene or setting change is detected, causing the rendering process to restart. Set to 0 to remove this limit.
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Enable Fractional Cutout Opacity |
If enabled, fractional cutout opacity values are treated as a measure of surface ‘presence’, resulting in a translucency effect similar to alpha-blending. Path-traced mode uses stochastic sampling based on these values to determine whether a surface hit is valid or should be skipped.
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Reset Accumulation on Time Change |
If enabled, the Path-Tracer accumulation is restarted every time the MDL animation time changes. Settings this to false is useful to prevent accumulation reset at every frame when the ‘animation time’ is changing every frames using wallclock time (which can be the case when we an animation is not being played, and wallclock time is used instead of animation time).
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Note
While using a higher number of bounces increases accuracy of the final image, it can quickly reduce performance while achieving diminishing returns in terms of image quality.
Sampling & Caching¶
Setting |
Effect |
|---|---|
Enable Caching |
Enables a technique that caches path tracing results for improved performance at the cost of some correctness.
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Enable Many-Light Sampling |
Enables a technique that improves the sampling quality (and therefore rendering convergence) in scenes with many light primitives.
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Denoising¶
Setting |
Effect |
|---|---|
Denoising |
Enable to apply the OptiX Denoiser to the radiance image generated by the renderer. The OptiX denoiser results in an order of magnitude reduction in rendering times for a target image quality.
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Optix Denoiser Blend Factor |
A blend factor indicating how much to blend the denoised image with the original non-denoised image. A value of 0 shows only the denoised image, while a value of 1.0 shows the image with no denoising applied.
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Path-Traced Fog¶
Setting |
Effect |
|---|---|
Path-Traced Fog |
Enables Path-Traced fog using volume absorption and scattering simulation with a Henyey-Greenstein phase function. The number of bounces is controlled by Max Fog Scattering Bounces.
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Density |
The density of the fog medium.
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Height |
The maximum height of the fog volume.
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Falloff |
Exponential fall-off of the fog.
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Color |
The color of the fog medium.
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Asymmetry (g) |
The asymmetry of the Henyey-Greenstein phase function (“g” parameter).
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Use +Z Axis for Height |
If set the volume height is considered along the positive Z. Otherwise use the positive Y axis.
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Non-uniform Volumes¶
This feature enables path-traced volume rendering of both VDB files (internally converted to NanoVDB, a faster and more compact GPU-friendly volume representation) and procedural MDL based volumes. VDB files can either contain a SDF (signed distance field/level set) or density volume. Currently, the VDB volume material can only be applied to a cube mesh, while procedural volume materials can be applied to any kind of mesh (cube, sphere, torus, etc). Volumes can also overlap with other volumes. The maximum number of overlaps between the volumes is currently limited to four.
Setting |
Effect |
|---|---|
Non-uniform Volumes |
The number of bounces is controlled by Max Heterogeneous Volume Scattering Bounces (under the Path-Tracing section in Path-Traced Mode Settings).
• When set to 1: perform single scattering. Fast, suitable for lowly scattering volumes like fog.
• When set to a value greater than 1: perform multi-scattering. Slower, suitable for highly scattering volumes like clouds.
Important: Make sure to increase the number of bounces to avoid darkening artifacts.
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Transmittance Method |
Choose between Biased Ray Marching, Ratio Tracking or Brute-Force Ray Marching. Biased ray marching is the ideal option in all cases.
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Max Collision Count |
Maximum delta tracking iterations. Increase to more than 32 for highly scattering volumes like clouds.
Important: if set too low, parts of the volume will disappear.
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Max Light Collision Count |
Maximum ratio tracking iterations. Increase to more than 32 for highly scattering volumes like clouds.
Important: if set too low, parts of the volume will disappear.
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Constant Majorant |
How to create a VDB volume object¶
Create a cube mesh
In the cube’s Property tab, check isVolume
Assign VDBTestMaterial.mdl to the cube
In the Property tab of the VDBTestMaterial, assign a VDB file to the volume_density_texture
How to create a procedural volume object¶
Create a cube mesh
In the cube’s Property tab, check isVolume
Assign either perlinNoise.mdl or worleyNoise.mdl to the cube
Multi-GPU¶
Setting |
Effect |
|---|---|
Multi-GPU |
Enables the use of multiple GPUs in path-traced mode (when these are available and enabled at startup). Multi-GPU must be enabled at startup by passing adding –/renderer/multiGpu/enabled=true to the command line.
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GPU 0 Weight |
The amount of total Path-Tracing work (between 0 and 1) to be performed by the first GPU in a Multi-GPU configuration. A value of 1 means the first GPU will perform the same amount of work assigned to any other GPU.
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Compress Radiance |
Enables lossy compression of per-pixel output radiance values.
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Compress Albedo |
Enables lossy compression of per-pixel output albedo values (needed by OptiX denoiser).
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Compress Normals |
Enables lossy compression of per-pixel output normal values (needed by OptiX denoiser).
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Multi-Threading |
Enabling multi-threading improves UI responsiveness.
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