Radeon ProRender

Ray Depth Settings

When an image is rendered, multiple light rays are emitted through each pixel of the image plane. As they encounter obstacles, the light rays bounce around the scene contributing to the surface color and brightness, and this process might be as long as infinite, whereas for a decent render output, a limited number of ray bounces is usually sufficient.

In AMD Radeon ProRender, the number of times that a ray bounces off various surfaces before being terminated is controlled with the Ray Depth parameters.

Increasing the ray depth results in more time taken to complete the rendering process. When looking for a compromise between the render time and the image quality, start with the defaults offered by the plug-in and experiment with greater values. A good rule of thumb is to increase the ray depth if there is missing light or you feel there should be complex light paths in the rendered scene.

In AMD Radeon ProRender, the ray depth can be limited separately for different types of surfaces, such as diffuse, glossy, refraction, glossy refraction or shadow. This allows you to describe how many bounces light should take off each surface type, and might be particularly useful for scenes with certain types of materials predominating, as this helps optimize the render time.

Ray Depth Max

The Ray Depth Max parameter limits the total number of ray bounces for all types of surfaces and components, whether they are diffuse, reflective or refractive. This threshold cannot be exceeded even if the sum of Ray Depth values for specific surfaces is greater than the specified total.

In general, the default value of 8 is suitable for most scenes, unless these scenes include translucent or complex materials.

Ray Depth Diffuse

The Ray Depth Diffuse parameter controls the maximum number of times that a light ray can be bounced off diffuse surfaces. In general, greater Ray Depth Diffuse values make the scene brighter by providing more bounce light in the scene. It is rare to need a Ray Depth Diffuse value greater than 3, as this will usually have negligible effect.

Ray Depth Glossy

The Ray Depth Glossy parameter controls the maximum number of ray bounces from specular surfaces. This value does not need to be large for scenes with rough surfaces, while for scenes with perfectly smooth and mirror surfaces the Ray Depth Glossy value needs to be increased to capture specular reflections.

Ray Depth Refraction

The Ray Depth Refraction parameter controls the maximum number of times that a light ray can be refracted, and is designated for clear transparent materials, such as glass.

The Ray Depth Refraction value should be set large for scenes with many nested transparent objects.

Ray Depth Glossy Refraction

The Ray Depth Glossy Refraction parameter is similar to the Ray Depth Refraction parameter. The difference is that it is aimed at working with matte refractive materials, such as semi-frosted glass.

Ray Depth Shadow

The Ray Depth Shadow parameter controls the accuracy of shadows cast by transparent objects. It defines the maximum number of surfaces that a light ray can encounter in its path causing these surfaces to cast shadows. Greater Ray Depth Shadow values produce softer and more accurate shadows but increase the rendering time.

Note

When passing through a three-dimensional object, a light ray encounters two boundaries: once upon entering the material, and once upon exiting it. Consider this when choosing the right Ray Depth Shadow value.