Path Tracer
The highest quality offline renderer.
Path Tracer
Method #
This node is our highest quality Renderer, utilising pathtracing to render images with full global illumination, reflections, and refractions.
Suitable for rendering 3D content at the highest quality in stills or exporting to video.
Parameters
Parameter Details Max Refine Steps The max number of refine steps per frame. Early refinement steps will converge very quickly, but over time the scene will take longer to converge. The right number of refines varies greatly from scene to scene, so it’s wise to start with a lower number and bump it up incrementally until an acceptable balance of noise and render time is found.
Refining Mode Control how the image is refined.
- Full Refining : Every pixel is refined for the full number of refinement steps.
- Adaptive Refining : Every pixel is checked to see how much it has changed over a number of refinement steps. if the differences are smaller than the threshold, then that pixel stops refining. Useful for optimising the refinement process, as it focuses refinement onto areas of high noise, so more refinement steps can be done without in a shorter period of time. On scenes which are already very noisey, the difference may be miniscule though.
Adaptive Threshold The threshold used for adaptive refinement. Higher values mean refinement will stop sooner, but can also skip areas which need more refinement. Similarly, lower values will take longer to refine, but the resulting image will have much less noise. The right balance for your scene will vary, so try a few values to help hone in on the one you feel is most appropriate.
Diffuse Depth How many bounces of Diffuse lighting is used. More bounces can increase the brightness in dark areas of the scene, but will have deminishing retuns at greater values.
Glossy Depth How many bounces of Specular lighting are used. More bounces may be necessary in scenes with lots of clean glass or mirrors, but in scenes with lots of rough surfaces lower values can be used to improve performance.
Refraction Depth How many refractive are used. Similar to glossy depth, more bounces may be necessary in scenes with lots of glass, but in scenes with no glass or lots of rough glass lower values can be used to improve performance.
Antialiasing These options allow for different methods of reducing aliasing. For more about aliasing and anti-aliasing, see here… [LINK]
- FSAA : Each ray is slightly diverted at a subpixel level, producing extremely accurate antialiasing which improves with further refinement steps.
- None : No Anti-Aliasing is applied to the scene.
Depth Of Field Controls how depth of field is generated in the scene.
- Depth Of Field : Offsets the starting position of every ray based on the cameras blurrines and focus parameters. Useful for drawing focus onto a specific area of the scene.
- None : No depth of field is generated in the scene.
Motion Blur How motion blur is generated in the scene.
- Motion Blur : Motion vectors for all objects in the scene are used to predict where objects will be inebtween frames, and rays are cast which intersect with those object with a random offset in time. Gives fast and accurate results, but can generate strange smears if an object moves too erratically.
- None : No motion blur is generated in the scene.
Ambient Occlusion Simulates natural shadowing that occurs in corners and crevices of a scene, by darkening those areas. Useful for exaggerating detail in a scene.
- Raytraced : The scene is raytraced by a global emissive light sourcec, so darkened areas will naturally receive less light.
- Off : No Ambient Occlusion is generated.
AO Blend Mode Controls how the generated Ambient Occlusion is applied to the scene.
- Multiply : The Ambient Occlusions is multiplied against the scene after all the lighting passes have been generated.
- Replace : Replaces the current lighting with that of the Ambient Occlusion. Useful for getting a simple clay render of the scene.
- Add : Adds the Ambient Occlusion lighting on top of the lighting of the scene, brightening all areas except the areas the ambient occlusion is applied.
AO Blend Amount How much the chosen blend mode is applied into the scene. Doesnt apply to replace blend mode.
AO Distance Controls how wide the Ambient Occlusion radius is. Lower values tighten the ambient occlusion to smaller areas, larger value can end up darkening the whole object, and add visible noise which will need to be refined.
AO Falloff Curve Controls how the weighting of ambient occlusion falls off over distance. Higher values will darken areas of ambient occlusion further, while lower values will lessen the ambient occlusion except in narrow crevices.
Scattering Control how light scattering is applied in the scene.
- Scattering : Uses a full raytraced scattering model.
- None : No light scattering is generated in the scene.
Scattering Intensity Multiplier on top of the global scattering density. Useful for adjusting the density globally without going to all the individual lights.
Scattering Max Distance The maximum distance the volumetric lighting tests against in the scene. Higher values will improve quality at a distance, but can reduce performance.
Brightness Clamp Sets a maximum output brightness value when sampling light in the scene. Useful for reducing ‘firefly’ noise in the scene, as further light samples are likely to average out faster, but can reduce the overall lighting accuracy in the scene.
Diffuse Bounce Multiplier Boost the brightness of diffuse bounces in the scene. Useful for artificially brightening unlit areas of a scene without adding extra diffuse bounces, but not accurate and if pushed too far can introduce artefacting and blow up the lighting model as surfaces reflect more light than they absorb.
Kill Caustic Paths Kills rays which the pathtracer identifies as caustic, and contribute noise which is difficult to refine.
AI Denoiser Uses an AI denoiser to denoie the final refined result. Each denoiser uses data from the GBuffer to denoise the scene, so reflective and refractive surfaces can often get denoised more aggressively than expected and often arent suitable or denoising..
- None : No denoiser is used.
- Intel OIDN (cpu) : Enables the Intel OIDN denoiser. Slow, but gives a good result.
- NVIDIA Optix (gpu) : Enables the NVIDIA Optix denoiser. Fast, but can be a bit smeary even with lots of refinement steps.
Denoising Mode Control when a denoiser is applied to the scene, if denoising is enabled.
- Per Refine Step : The denoiser is applied every step of the refinement.
- After Refining : The denoiser is applied only after the entire frame has been fully refined.
Irradiance Cache Use light probes to help guide the paths for raytracing. Can optimise scenes with lots of lights or lots of geometry, but generally not necessary for pathtraced scenes.
- None : Probes are not generated, and the irradiance cache is not used.
- Path Guiding : Probes are used to guide the paths for raytracing to wards brighter areas of the scene.
- Bounce : Probes are used for the secondary bounces of the scene, rather than raytracing all the diffuse bounces.
Irradiance Cache Bounce TBC
Probe Separation Distance The minimum distance betweeen light probes in the scene. Higher probe densities can improve quality of bounce lighting to a point, but can impact performance. Only used when Irradiance Cache is enabled.
Inputs
| Parameter | Details |
|---|---|
| Max Refine Steps | The max number of refine steps per frame. Early refinement steps will converge very quickly, but over time the scene will take longer to converge. The right number of refines varies greatly from scene to scene, so it’s wise to start with a lower number and bump it up incrementally until an acceptable balance of noise and render time is found. |
| Refining Mode | Control how the image is refined.
|
| Adaptive Threshold | The threshold used for adaptive refinement. Higher values mean refinement will stop sooner, but can also skip areas which need more refinement. Similarly, lower values will take longer to refine, but the resulting image will have much less noise. The right balance for your scene will vary, so try a few values to help hone in on the one you feel is most appropriate. |
| Diffuse Depth | How many bounces of Diffuse lighting is used. More bounces can increase the brightness in dark areas of the scene, but will have deminishing retuns at greater values. |
| Glossy Depth | How many bounces of Specular lighting are used. More bounces may be necessary in scenes with lots of clean glass or mirrors, but in scenes with lots of rough surfaces lower values can be used to improve performance. |
| Refraction Depth | How many refractive are used. Similar to glossy depth, more bounces may be necessary in scenes with lots of glass, but in scenes with no glass or lots of rough glass lower values can be used to improve performance. |
| Antialiasing | These options allow for different methods of reducing aliasing. For more about aliasing and anti-aliasing, see here… [LINK]
|
| Depth Of Field | Controls how depth of field is generated in the scene.
|
| Motion Blur | How motion blur is generated in the scene.
|
| Ambient Occlusion | Simulates natural shadowing that occurs in corners and crevices of a scene, by darkening those areas. Useful for exaggerating detail in a scene.
|
| AO Blend Mode | Controls how the generated Ambient Occlusion is applied to the scene.
|
| AO Blend Amount | How much the chosen blend mode is applied into the scene. Doesnt apply to replace blend mode. |
| AO Distance | Controls how wide the Ambient Occlusion radius is. Lower values tighten the ambient occlusion to smaller areas, larger value can end up darkening the whole object, and add visible noise which will need to be refined. |
| AO Falloff Curve | Controls how the weighting of ambient occlusion falls off over distance. Higher values will darken areas of ambient occlusion further, while lower values will lessen the ambient occlusion except in narrow crevices. |
| Scattering | Control how light scattering is applied in the scene.
|
| Scattering Intensity | Multiplier on top of the global scattering density. Useful for adjusting the density globally without going to all the individual lights. |
| Scattering Max Distance | The maximum distance the volumetric lighting tests against in the scene. Higher values will improve quality at a distance, but can reduce performance. |
| Brightness Clamp | Sets a maximum output brightness value when sampling light in the scene. Useful for reducing ‘firefly’ noise in the scene, as further light samples are likely to average out faster, but can reduce the overall lighting accuracy in the scene. |
| Diffuse Bounce Multiplier | Boost the brightness of diffuse bounces in the scene. Useful for artificially brightening unlit areas of a scene without adding extra diffuse bounces, but not accurate and if pushed too far can introduce artefacting and blow up the lighting model as surfaces reflect more light than they absorb. |
| Kill Caustic Paths | Kills rays which the pathtracer identifies as caustic, and contribute noise which is difficult to refine. |
| AI Denoiser | Uses an AI denoiser to denoie the final refined result. Each denoiser uses data from the GBuffer to denoise the scene, so reflective and refractive surfaces can often get denoised more aggressively than expected and often arent suitable or denoising..
|
| Denoising Mode | Control when a denoiser is applied to the scene, if denoising is enabled.
|
| Irradiance Cache | Use light probes to help guide the paths for raytracing. Can optimise scenes with lots of lights or lots of geometry, but generally not necessary for pathtraced scenes.
|
| Irradiance Cache Bounce | TBC |
| Probe Separation Distance | The minimum distance betweeen light probes in the scene. Higher probe densities can improve quality of bounce lighting to a point, but can impact performance. Only used when Irradiance Cache is enabled. |
| Name | Description | Typical Input |
|---|---|---|
| Probe Separation Distance | TBC | TBC |
| Ray Bias | TBC | TBC |
| Scattering Intensity | TBC | TBC |
| Scattering Max Distance | TBC | TBC |
| AO Distance | TBC | TBC |
| AO Blend Amount | TBC | TBC |
| AO Falloff Curve | TBC | TBC |