V-Ray Mtl Options

The Options tab is part of the V-Ray Mtl parameters.

Options

Cutoff – A threshold below which reflections/refractions cannot be traced. V-Ray tries to estimate the contribution of reflections/refractions to the image, and if it is below this threshold, these effects are not computed. Do not set this to 0.0, as it may cause excessively long render times in some cases.

Preserve Energy – Determines how the diffuse, reflection, and refraction color affect each other. V-Ray tries to keep the total amount of light reflected off a surface to be less than or equal to the light falling on the surface (as this happens in real life). For this purpose, the following rule is applied: the reflection level dims the diffuse and refraction levels (a pure white reflection removes any diffuse and refraction effects), and the refraction level dims the diffuse level (a pure white refraction color removes any diffuse effects). This parameter determines whether the dimming happens separately for the RGB components (RGB) or is based on the intensity (Monochrome).

LPE Label – Allows a label to be assigned, which can be used to reference the material in a Light Path Expression. This is especially useful when working with the Light Select render channel to evaluate custom light contribution in the scene.

Quick Sun Caustics

This rollout provides “quick” caustics settings. Useful when creating simple water scenes. The “quick” caustics are not as physically accurate as the normal V-Ray caustics, but they render quicker and are high-quality enough for simple scenes. Quick caustics are supported only with the Light Cache sampler. Light Cache is enabled for production rendering by default. To enable it for IPR, go to the Render Settings > GI Tab > Use Light Cache for Interactive Rendering. For more details, see the GI Tab page.

Quick Caustics are not supported on V-Ray GPU.

Reflection – When enabled, “quick” reflection caustics are cast by the material.

Refraction – When enabled, “quick” refraction caustics are cast by the material.

Depth (affects the corresponding property above) – Determines the maximum distance from the surface at which the effect is visible. Measured in scene units. Use the minimum required depth for optimal render times.