Basic parameters Min rate - this value determines the resolution for the first GI pass. Larger images usually can do with lower Min/Max rates than those specified in the presets. Note that the presets are targeted for a typical 640x480 image. Very high - a very high quality preset can be used for scenes with extremely small and intricate details. High animation - a high-quality preset that can be used if the High preset produces flickering in animations the Distance threshold is higher. High - a high-quality preset that works in most situations, even for scenes with small details as well as for most animations. Medium animation - a medium quality preset targeted at reducing flickering in animations - the Distance threshold is higher. Medium - a medium quality preset works fine in many situations in scenes which have don't small details. Low - a low-quality preset for preview purposes Very low - this preset is only useful for preview purposes to show the general lighting in the scene.

You can use these to quickly set the color, normal and distance thresholds, as well as the min/max rates. Parameters Built-in presets Current preset - this dropdown list allows you to choose from several presets for some of the irradiance map parameters. During the actual rendering, V-Ray uses a sophisticated interpolation method to derive an approximation of the irradiance for all surfaces in the scene

If not, the indirect illumination for the current point is computed, and that point is stored in the irradiance map. Based on that information, V-Ray decides if the indirect illumination for the current point can be adequately interpolated from the points already in the irradiance map, or not. if there are any objects close by, how fast the indirect illumination is varying etc). From those already computed points, V-Ray can extract various information (i.e. When an object is hit during a GI pass, V-Ray looks into the irradiance map to see if there are any points similar in position and orientation to the current one. The irradiance map is in fact a collection of points in 3d space (a point cloud) along with the computed indirect illumination at those points. The idea is to start with a low resolution (say a quarter of the resolution of the final image) and work up to the final image resolution. This is done by rendering the image several times (each rendering is called a pass) with the rendering resolution being doubled withД®ach pass. The irradiance map is therefore built adaptively. where objects are close to each other, or in places with sharp GI shadows), and less accurately in uninteresting parts (e.g. Since not all parts of the scene have the same detail in indirect illumination, it makes sense to compute GI more accurately in the important parts (e.g. In V-Ray, the term irradiance map refers to a method of efficiently computing the diffuse surface irradiance for objects in the scene. In more simple terms, one can think of the diffuse surface irradiance as being the visible color of a surface, if we assume that its material is purely white and diffuse. The second restriction is that of diffuse surface irradiance - which is the total amount of light arriving at a given surface point, disregarding the direction from which it comes. This is a natural restriction since we are usually interested in the illumination of objects in the scene, and objects are usually defined through their surface.

The first is the surface irradiance - which is the irradiance arriving at points which lie on the surface of objects in the scene.

However, there are two useful restrictions that can be made. In general, irradiance is different in every point and in every direction. Irradiance is a function defined for any point in the 3D space and represents the light arriving at this point from all possible directions. Some background for understanding how the irradiance map works is necessary in order to grasp the meaning of these parameters. This section is enabled only when the irradiance map is chosen as the GI method for primary diffuse bounces. Irradiance Map General This section allows the user to control and fine-tune various aspects of the irradiance map.

Irradiance map vray settings