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.

Attributes

Name Description
Samples The number of rays per pixel per frame.
Max. Diffuse Depth Maximum number of diffuse bounces calculated per ray.
Ray Bias Biases the ray start position away from the spawning surface – to reduce fighting artefacts in exchange for less accuracy.
Sample Clamp Sets a maximum brightness for each pixel to help reduce noise and bright hot-spots.
Diffuse Bounce Multiplier Change how effective the bounce lighting is in the scene.

Inputs

Name Description Typical Node Input
Object Nodes Only nodes input will be used for diffuse bounces. 3D Object
Transform Modifier Links all transform properties to the input node. Null
Target Node Always faces the x-axis towards the inputs anchor point. Null
Local Transform Override Override the transformation values of the node, relative to its parent. Null

Outputs

All nodes connected to this node are treated as if flowing to the parent node, and inherits any transformation changes along the chain.