I often see people talk about fireflies in their renders and it kills me.

The “grain” that we see on screen, while the image is still unfinished, is called render noise.

Render noise is gradually removed as the scene renders. The time needed to achieve this is depending on many factors, including:

  • Number of CPU cores and their speed
  • Size of the image
  • Number of light or light sources in the scene • Amount of glossiness in reflective surfaces

Sometimes we see the term “fireflies” used to indicate render noise. That is not correct. Fireflies are mostly a thing of the past and they don’t happen today with LuxRender, except in the most extreme cases. Fireflies are not render noise. Instead they are large “specks” of white pixels, much larger than render noise, and they don’t get resolved over time. In fact they tend to become more pronounced as the render continues.

When we use the wrong term publicly we do a disservice to others. It spreads the use of the wrong term and it covers what is really happening. It also makes the work of supporting Reality much harder.

I beg you, please use the expression “render noise” when you refer to the grain and only use fireflies when is appropriate, which is usually never.

Thank you very much for your help.


Pin on PinterestShare on FacebookTweet about this on TwitterShare on Google+