From the course: V-Ray Next for 3ds Max Essential Training

Image sampling explained - 3ds Max Tutorial

From the course: V-Ray Next for 3ds Max Essential Training

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Image sampling explained

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such as V-Ray, I think a basic understanding of the technology In order to collect all of the information that we need, so as to create a final render from a 3D environment, such as the shape of geometric objects, the surface and volume properties of any materials that may have been applied, lighting and shadow information etcetera, our render engine needs to somehow probe the 3D scene in order to determine just what are to be drawn in each of the pixels or squares that will ultimately make up the final image. The million-dollar question of course is, how will this gathering of information, or scene probing, be accomplished? Well, this is where understanding at least a little bit, regarding the basic workings of the raytrace process, In general terms then, ray tracing works like this: From the rendering camera in the scene, the render engine will shoot a number of rays through an internal frame buffer or grid that represents each of the pixels making up the final image. sometimes referred to as eye or camera rays, are sent out into the 3D environment in order to trace or bounce their way through the scene, usually with a predetermined limit as to the number of times that they are allowed to bounce. As they go, these rays sample or gather information from any objects found in their path. As they hit or come into contact with surfaces, such as diffuse color values, specular reflectivity levels, and so on. They also, with every hit, send out shadows rays whose very specific job it is to trace a line from the point of contact on a surface, toward any direct light sources that can be found in the environment. This determines whether or not a particular surface point should be rendered as sitting in direct light or perhaps in deepest shadow. These primary rays will also, on contact with a surface, make an evaluation as to whether or not any secondary rays are required. These come into play when a surface material has properties such as refraction, blurred reflections, subsurface scattering, and so on, added to it. Once a user-specified amount of sampling or information gathering has been accomplished, back along each of the rays' traveled paths, fed into the render engine for evaluation and averaging, and then gets drawn in the frame buffer as a final pixel color value. Of course, this is an extremely simplified overview of what is in reality an incredibly complex process that can potentially involve millions of different kinds of rays being cast and then traced throughout our scenes. This is enough for us to work with in this course though and will definitely help when we have sampling or image quality decisions or image quality decisions that need to be made further on down the line. that need to be made further on down the line. Let's move on to a second critical concept Let's move on to a second critical concept when it comes to image quality in V-Ray now, when it comes to image quality in V-Ray now, and take a look at the subject of subdivs and take a look at the subject of subdivs or subdivisions in the engine. or subdivisions in the engine.

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