Radeon ProRender

Advanced Quality Settings

Advanced settings are aimed at improving the render result by removing artifacts that might appear in certain cases, and at optimizing the render performance.

Raycast Epsilon

The Raycast Epsilon parameter determines an offset used to move light rays away from the geometry for ray-surface intersection calculations. The reflected ray starts at a certain distance from the surface rather than at the bounce-off point. This helps to avoid self-shadowing and lighting artifacts that are common for ray tracers and caused by roundoff errors.

The ray epsilon distance is measured in millimeters. The default value is 0.1 mm, which is quite accurate for mid-scale scenes. However, for larger scenes involving distant objects or small-scale scenes, this value might need to be adjusted.

Tuning the ray cast epsilon parameter can also be useful for scenes where two or more materials are in contact, or where there is little to no space between meshes.

Radiance Clamp

The Radiance Clamp parameter limits the intensity, or the maximum brightness, of samples in the scene. Greater radiance clamp values produce more brightness.

Clamping is an effective method to prevent fireflies (hotpixels) without increasing the render time. Note that enabling clamping makes the lighting and reflections in the scene dimmer, and also affects the intensity of caustics. To find the desired balance between noise reduction and the overall scene appearance, it is recommended to start with a high clamp radiance value and decrease it step by step to a level where fireflies are no longer present.