Radiosity Stopping Criterion - Concepts

The Radiosity Stopping Criterion dialog provides calculation parameters that control the Radiosity calculations. The settings chosen in this dialog will affect your calculation point accuracies as well as your renderings.

Stopping Criterion (% Light Absorbed)

The progressive refinement radiosity techniques AGi32 employs lead to a converging solution. In other words, with each subsequent radiosity step, and less light is reflected (and absorbed) and the amount of unabsorbed light diminishes with each pass. It is impossible to account for every photon of light with this calculation technique; instead calculations are processed until an acceptable amount of light is absorbed. This is called the Radiosity Stopping Criterion. The default Radiosity Stopping Criterion is 99% - meaning that 99% of the light has been absorbed and 1% is unaccounted for.

Radiosity Stopping Criterion - Accuracy vs. Calculation times

AGi32 processes the Radiosity calculations until the Stopping Criterion is met. Stopping Criterion indicates the amount of unabsorbed light that can remain in the environment before the Radiosity calculations are stopped. The default Stopping Criterion is 99%

For most Electric lighting applications, the environment will show little numerical change (the FC results will be stable) at a Stopping Criterion of 95%

For Daylighting applications, the calculations should not be stopped until the default Stopping Criterion is reached (99%) as the values can still fluctuate above acceptable tolerances.