This section is available only if you have chosen Brute force GI as either the primary or the secondary GI engine.

The brute force method for computing global illumination recomputes the GI values for every single shaded point separately and independently from other points.

While very slow, this method is very accurate, especially if you have many small details in the scene.

To speed up brute force GI, you can use a faster method (the Photon map or the Light cache) for approximating secondary GI bounces, while using the brute force method for the primary bounces or you can use the Brute force engine as the secondary bounce engine to combine and refine a Irradiance map GI solution.

The following diagram shows the way rays are traced when using the Brute Force GI. Since the method is view dependant the first rays (Black) are traced from the camera into the scene in order to determine the points for which GI is going to be calculated. Then the Primary bounces(Red) are traced into the scene – the number of rays traced depends on the Subdivs parameter. The Secondary bounce rays (Blue) are traced only when Brute Force GI is used for secondary GI engine. In that case a single ray is traced for each bounce and the number of bounces depends on the Secondary Bounces parameter.

Subdivision – this determines the number of samples used to approximate GI. Note that this is not the exact number of rays that VRAYforC4D will trace. The number of rays is proportional to the square of this number, but also depends on the settings in the DMC sampler rollout.

Ray depth – this parameter is available only if Brute Force GI is selected as a secondary GI engine. It controls the number of light bounces that will be computed.