How to get rid of excessive noise? Corona for Cinema 4D

Subtle high-frequency noise is normal for Corona and other path-tracing renderers, especially at the beginning of the rendering process. But strong noise that won't go away after many passes, or after long rendering time, may suggest that the rendering engine encountered some problems in your scene setup. Starting from Corona 1.4 you can use the denoising feature to get rid of the noise by smartly blurring it. It is however recommended to make sure that there are no mistakes in the render setup, or the scene itself.

To efficiently get rid of problematic noise, you need to find out where it comes from. Most common causes of persistent noise include:

Wrong material setup:

This is usually manifested by noise visible only in specific parts of the scene (some objects or some materials).

Scene lighting:

Noise is visible in strongly lit areas, on edges of light spots or shadows, or when light bounces off objects.

Wrong render settings:

Noise is visible in the whole image or in specific areas like direct light or light bouncing off objects.

Note: you can easily reset all Corona render settings to their default values - see: How to reset settings to their default values?

Fireflies in corners:

Single bright pixels visible in corners of the room or on geometry without thickness.

Noise in camera effects:

Noise is visible in areas affected by depth of field or motion blur effects.

Flickering/splotches in animation:

Apart from user errors, there are some physically-correct phenomena that can also cause "noise" effect in real life (for example in photography). This includes:

To determine the cause of noise, it may be sometimes useful to enable material override (see: How to create clay renders? ). If the noise is still visible after applying the diffuse grey material to all objects, it indicates that most probably it is not caused by scene materials.