Notch Notch Manual 0.9.23
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RT Diffuse Bounces

RT Diffuse Bounces

Renders Global Illumination with Ray Tracing.


Method #

The Diffuse Bounce node simulates diffuse lighting of solid objects accurately with support for multiple bounces. Only diffuse bounces and interactions are handled. This makes it particularly applicable for baking light maps, as the light interactions modelled are almost completely view-independent. This is achieved by casting lots and lots of rays, randomly distributed, and accumulating the results. The sum of all the random rays ends up with a smooth, converged image over time. As such this node can be very slow and is not intended for real-time use.

Typically, only a very small number of rays per pixel can be cast per frame at real-time rates - but to produce a converged image, hundreds or thousands of rays must be accumulated per pixel. It is possible to use the “Samples” parameter to control how many rays are cast per pixel per frame at the cost of longer frame times. However, the more common solution is to use continuous refinement. This casts few or even only one ray per pixel per frame, varying that ray randomly each time and averaging the result, so the image converges from noisy to smooth. When anything in the scene changes or animation occurs, refinement resets. This allows you to work on your scene using a fast but noisy render as you edit it; then leave it to refine for a few seconds to see how it looks when converged.

Raytracing will need to be enabled on the root node for this node to work.


These properties control the core behaviours of the node.

SamplesThe number of rays per pixel per frame.
Max. Diffuse DepthMaximum number of diffuse bounces calculated per ray.
Ray BiasBiases the ray start position away from the spawning surface - to reduce fighting artefacts in exchange for less accuracy.
Sample ClampSets a maximum brightness for each pixel to help reduce noise and bright hot-spots.
Diffuse Bounce MultiplierChange how effective the bounce lighting is in the scene.


NameDescriptionTypical Input
Object NodesOnly nodes input will be used for diffuse bounces.3D Object
Transform ModifierApply the transforms of another node to this node.Null
Target NodeModifiy the rotations of the node to always direct the z axis towards the input.Null
Local Transform OverrideApply the transforms of another node to this node, relative to its parent.Null