Threshold for limiting updates of Enlighten Realtime Global Illumination. The unit of measurement is "percentage intensity change".
Describes how much input lighting can change before the real-time lightmap is updated. When input lighting is updated, Enlighten Realtime Global Illumination keeps a running total of the difference in input lighting intensity since the last time lighting was solved. The current difference is added each update, so over time it is the sum of the differences since the last solve. Each update, Enlighten Realtime Global Illumination checks whether the running total of light intensity exceeds the previous result by a difference specified by the updateThreshold value as a percentage.
Lower values mean the real-time lightmap will be updated more frequently but will incur more CPU load. Higher values will result in it being updated less frequency, but will incur a lighter CPU load.
A value of 0 means that the real-time lightmap will update even on the smallest change in the input lighting. If the input lighting doesn't change, a value of 0 will not cause any updates to the lightmap. A positive value causes the Global Illumination to only update when the threshold is exceeded. This is useful for saving CPU cycles and updating those parts of the Scene where the lighting is being changed more frequently rather than other areas where the lighting is mostly static. The default value is 1%. Any positive value is fine but we recommend smaller values, as otherwise you might see popping artefacts (and incorrect radiosity).
如果您想节约更多 CPU 周期，那么您没有理由不能超过 100%。该百分比实际上是解算发生前的最大容错。
任何负值都会关闭时间相干性，因此即使照明没有改变，在每一帧也都会对系统进行解算。
请注意，更高强度值的解算频率低于更低强度值，这是有意义的，因为我们认为低强度光源中的差异比高强度光源中的差异更大。