OSPRay renderer

This is a software-based raytracing renderer. It can produce renderings of the scene with global illumination, shadows and depth of field. The OSPRay renderer has a smaller memory footprint than the Tachyon renderer. It can thus be used for rendering very large datasets, with a higher visual quality than the OpenGL renderer is able to provide.

The OSPRay renderer itself offers two different backends and you can switch between them using the Switch OSPRay backend button. The default selection is the SciVis backend.

For more information on the capabilities of the OSPRay engine and technical background information beyond what is found here, please visit the www.ospray.org website.


Refinement passes

The OSPRay renderer supports a feature called adaptive accumulation, which is a progressive rendering method. During each rendering pass, the rendered image is progressively refined. This parameter controls the number of iterations until the refinement stops (default: 8).

Samples per pixel

The number of raytracing samples computed per pixel (default: 4). Larger values can help to reduce aliasing artifacts.

Max ray recursion depth

The maximum number of recursion steps during raytracing. Normally, 1 or 2 is enough, but when rendering semi-transparent objects, a larger recursion depth is needed.

Direct light

Controls the directional light source that is positioned behind the camera and is pointing roughly along the viewing direction. The angular diameter parameter specifies the apparent size (angle in degree) of the light source. Setting the angular diameter to a value greater than zero will result in soft shadows when the rendering backend uses stochastic sampling (only the case for the Path Tracer backend). For instance, the apparent size of the sun is about 0.53°.

Ambient light

The ambient light surrounds the scene and illuminates it from infinity with constant radiance.


The specular brightness controls the specular reflectivity of the material (default: 5%). The shininess parameter (specular Phong exponent) is usually in the range between 2.0 and 10,000 (default: 10.0).

Depth of field

Only objects exactly at the distance from the camera specified by the focal length will appear sharp when depth-of-field rendering is active. Objects closer to or further from the camera will appear blurred. If you want a specific object to be in the focus, use the Pick in viewport button and click on that object in the viewport to be rendered. The focal length parameter will be automatically adjusted so that the picked location is in focus. The aperture radius controls how blurred objects will appear that are out of focus (default: 0.5).

SciVis backend

The SciVis backend is a fast ray tracer for scientific visualization, which supports ambient occlusion (AO).


Controls whether to compute (hard) shadows.

Ambient occlusion

Ambient occlusion mimics some of the effects that occur under conditions of omnidirectional diffuse illumination, e.g. outdoors on an overcast day. The sample count parameter determines the number of rays per sample to compute for ambient occlusion (default: 12).

Path Tracer backend

The path tracer backend supports soft shadows, indirect illumination and realistic materials.

Roulette depth

Ray recursion depth at which to start Russian roulette termination (default: 5).

See also

OSPRayRenderer (Python API)