Path Tracer v1.2.1

Summary

Path Tracer is a GPU-accelerated physically-based renderer that uses the POPs accelerated structure (ray query extension) to compute ray-geometry intersections. This operator implements Monte Carlo path tracing with the Disney principled BRDF material model, enabling realistic lighting and material simulation. The path tracer supports progressive rendering for clean convergence and depth of field effects through aperture simulation.

In addition to geometry path tracing, Path Tracer includes a voxel tracer for rendering volumetric data with support for isosurface, volume, or blending between rendering modes. Hybrid tracing mode enables both the voxel tracer and geometry path tracing to render together, combining volumetric and surface-based rendering in a single pass.

The operator provides comprehensive material controls following the Disney BRDF standard, including base color, metallic/roughness workflows, specular reflections with anisotropic highlights, subsurface scattering, sheen for fabric-like materials, clearcoat layering, and transmission for glass. Lighting is handled through environment maps (HDR images) and direct light sources (point, spot, and area lights) with full transform controls. You can override existing materials on input geometry or respect per-primitive material attributes.

Path Tracer renders images to the Render TOP specified in the parameter. Progressive rendering accumulates samples over time for noise reduction. The renderer supports adjustable ray counts per pixel, bounce depth limits, and camera effects including depth of field with focal length and aperture controls. Path Tracer also supports real-time path tracing using a custom SVGF denoiser. This makes Path Tracer ideal for high-quality offline rendering, lookdev workflows, physically accurate lighting studies, or real-time path tracing of complex scenes.

Parameters

Page: Path Tracer

Enable Path Tracing Enabletracing – Master toggle for path tracing rendering.
Enable Hybrid Tracing Enablehybridtracing – Enables hybrid tracing mode that renders both the voxel tracer and geometry path tracing together.
Reset Reset – Pulse to reset progressive accumulation and restart rendering.
Lock Input Lockinput – Freeze input geometry to prevent updates during progressive rendering.
Progressive Rendering Progressiverendering – Accumulate samples over time for noise-free convergence.
Project On Geometry Projectongeometry – Projects the path traced result onto the input geometry surface.
Render TOP Rendertop – Reference to Render TOP providing camera and viewport settings that the path tracer will render to.
Rays per Pixel Raysperpixel – Number of rays cast per pixel per frame.
Max Bounces Maxbounces – Maximum ray bounce depth for global illumination.
Ray Offset Rayoffset – Offset distance for ray origins to prevent self-intersection artifacts.
Focal Length Focallength – Distance from camera where objects are in sharp focus.
Aperture Aperture – Camera aperture size for depth of field.
Show Focal Plane Showfocalplane – Displays the focal plane in the viewport for visualization.
Focal Plane Size Focalplanesize – Size of the focal plane visualization.

Page: Material

Attribute Class Attrclass – – Selects which attribute class the material properties are applied to.
Point point
Primitive primitive
Override if Material Exists Overrideifexists – Apply material parameters even when geometry has existing material attributes.
Base Color Basecolor – – Diffuse albedo color.
Base Color Basecolorr
Base Color Basecolorg
Base Color Basecolorb
Metallic Metallic – Metallic appearance.
Roughness Roughness – Surface roughness.
Specular Specular – Specular reflection strength for dielectrics.
Specular Color Specularcolor – – Tint specular reflection with color.
Specular Color Specularcolorr
Specular Color Specularcolorg
Specular Color Specularcolorb
Anisotropic Anisotropic – Anisotropic highlight stretching.
Anisotropic Rotation Anisotropicrot – Rotation angle for anisotropic highlights.
Subsurface Subsurface – Subsurface scattering amount for translucent materials like skin or wax.
Sheen Sheen – Soft velvet-like reflection for fabrics and cloth.
Sheen Color Sheencolor – – Tint sheen reflection with color.
Sheen Color Sheencolorr
Sheen Color Sheencolorg
Sheen Color Sheencolorb
Clearcoat Clearcoat – Secondary specular layer for car paint or lacquered surfaces.
Clearcoat Gloss Clearcoatgloss – Glossiness of clearcoat layer.
IOR Ior – Index of refraction for dielectrics.
Transmission Transmission – Light transmission through surface for glass and transparent materials.
Dispersion Dispersion – Chromatic dispersion amount for refractive materials.
Emission Emission – – Emissive color for self-illuminating surfaces.
Emission Emissionr
Emission Emissiong
Emission Emissionb

Page: Voxel Tracer

Enable Voxel Tracing Enablevoxeltracing – Master toggle for voxel tracing rendering.
Render Mode Rendermode – – Selects the voxel rendering technique.
Volume volume
Isosurface surface
Hybrid hybrid
Render Mode Map Rendermodemap – 3D texture map that blends between isosurface and volume rendering.
Step Size Scale Stepsizescale – Multiplier for ray marching step size through the volume.
Use Custom Bounds Usecustombounds – Enables custom bounding box for the voxel volume.
Lower Bounds Lowerbounds – – Minimum XYZ coordinates of the voxelization volume.
Lower Bounds Lowerboundsx
Lower Bounds Lowerboundsy
Lower Bounds Lowerboundsz
Upper Bounds Upperbounds – – Maximum XYZ coordinates of the voxelization volume.
Upper Bounds Upperboundsx
Upper Bounds Upperboundsy
Upper Bounds Upperboundsz
Transform Order Xord – – Sets the order of scale, rotate, and translate operations for the voxel volume transform.
Scale Rotate Translate srt
Scale Translate Rotate str
Rotate Scale Translate rst
Rotate Translate Scale rts
Translate Scale Rotate tsr
Translate Rotate Scale trs
Rotate Order Rord – – Sets the order of rotation operations for the voxel volume transform.
Rx Ry Rz xyz
Rx Rz Ry xzy
Ry Rx Rz yxz
Ry Rz Rx yzx
Rz Rx Ry zxy
Rz Ry Rx zyx
Translate T – – Translation of the voxel volume in world space.
Translate Tx
Translate Ty
Translate Tz
Rotate R – – Rotation of the voxel volume in degrees.
Rotate Rx
Rotate Ry
Rotate Rz
Scale S – – Scale of the voxel volume per axis.
Scale Sx
Scale Sy
Scale Sz
Pivot P – – Pivot point for the voxel volume transform.
Pivot Px
Pivot Py
Pivot Pz
Uniform Scale Scale – Uniform scale factor applied to the voxel volume.
Density Scale Densityscale – Multiplier for volumetric density values.
Absorption Color Absorption – – Color filter applied to light absorbed within the volume.
Absorption Color Absorptionr
Absorption Color Absorptiong
Absorption Color Absorptionb
Scattering Coefficient Scatteringcoeff – Controls the amount of light scattered within the volume.
Threshold Channel Thresholdchan – – Selects which texture channel to use for isosurface threshold evaluation.
Luminance luminance
Red red
Green green
Blue blue
Alpha alpha
RGB Average rgbaverage
RGBA Average average
RGB Maximum rgbmax
RGBA Maximum max
Surface Threshold Surfacethreshold – Density value at which the isosurface is extracted from the volume.
Normal Smoothing Normalsmoothing – Smoothing factor for computed surface normals on the isosurface.
Metallic Map Metallicmap – 3D texture map for metallic material property on the isosurface.
Roughness Map Roughnessmap – 3D texture map for roughness material property on the isosurface.
Specular Map Specularmap – 3D texture map for specular reflection strength on the isosurface.
Specular Color Map Specularcolormap – 3D texture map for specular color tint on the isosurface.
Anisotropic Map Anisotropicmap – 3D texture map for anisotropic highlight stretching on the isosurface.
Anisotropic Rotation Map Anisotropicrotmap – 3D texture map for anisotropic highlight rotation on the isosurface.
Subsurface Map Subsurfacemap – 3D texture map for subsurface scattering on the isosurface.
Sheen Map Sheenmap – 3D texture map for sheen reflection on the isosurface.
Sheen Color Map Sheencolormap – 3D texture map for sheen color tint on the isosurface.
Clearcoat Map Clearcoatmap – 3D texture map for clearcoat layer on the isosurface.
Clearcoat Gloss Map Clearcoatglossmap – 3D texture map for clearcoat glossiness on the isosurface.
IOR Map Iormap – 3D texture map for index of refraction on the isosurface.
Transmission Map Transmissionmap – 3D texture map for light transmission on the isosurface.
Dispersion Map Dispersionmap – 3D texture map for chromatic dispersion on the isosurface.
Emission Map Emissionmap – 3D texture map for emissive color on the isosurface.

Page: Lights

Enable Environment Light Enableenv – Enable image-based lighting from environment map.
Environment Map Environmentmap – HDR environment texture.
Environment Map Intensity Envmapintensity – Multiplier for environment light contribution.
Render Environment Renderenv – Show environment map in background when rays miss geometry.
Enable Direct Lighting Enabledirectlight – Enable direct lighting.
Texture Map Resolution Texturemapres – – Resolution of the texture maps used for direct light evaluation.
Texture Map Resolution Texturemapresx
Texture Map Resolution Texturemapresy
Lights Lights – Sequence of light sources.
Light Comp Lights0lightcomp – Reference to a POPX Light tool defining light properties.

Page: Post

Enable Tone Map Enabletonemap – Apply tone mapping to convert HDR output to display range.
Exposure Exposure – Exposure multiplier for tone mapping.
Gamma Gamma – Gamma correction value for tone mapping output.
Enable SVGF Enablesvgf – Enable SVGF denoiser for real-time noise reduction.
Color Box Scale Colorboxscale – Scale factor for the color bounding box used in temporal reprojection.
Max History Maxhistory – Maximum number of frames to accumulate in temporal history.
Normal Threshold Normalthreshold – Threshold for surface normal similarity in temporal reprojection.
Depth Threshold Depththreshold – Threshold for depth similarity in temporal reprojection.
Kernel Radius Kernelradius – Radius of the variance estimation kernel.
Normal Sensitivity Varnormalsensitivity – Sensitivity to surface normal differences in variance estimation.
Depth Sensitivity Vardepthsensitivity – Sensitivity to depth differences in variance estimation.
Passes Passes – Number of a-trous wavelet filter passes for spatial denoising.
Color Sensitivity Colorsensitivity – Sensitivity to color differences in a-trous filtering.
Normal Sensitivity Trousnormalsensitivity – Sensitivity to surface normal differences in a-trous filtering.
Depth Sensitivity Trousdepthsensitivity – Sensitivity to depth differences in a-trous filtering.
Roughness Sensitivity Roughnesssensitivity – Sensitivity to roughness differences in a-trous filtering.

Page: Common

Free Extra GPU Memory Freeextragpumem – Free memory that has accumulated when output memory has grown and shrunk.

Inputs

Input 0 POP – Geometry
Input 1 TOP – Voxels