In raytracing, one or more rays of light are tracked from the camera to the next 3D object for each pixel of the scene. The light beam is then guided through a fixed number of bounces, which can include reflection or refraction depending on the material of the 3D scene. The color of each pixel is algorithmically calculated based on the interaction of the light beam with the objects in its traced path. Raytracing is able to produce more photorealism than Scanline, but is exponentially slower.
In contrast to raytracing, radiosity is calculated independently of the camera and is not pixel-oriented, but surface-oriented. The primary function of radiosity is to simulate the surface color more accurately by considering indirect illumination (pressed diffuse light). Radiosity is typically characterized by soft, graded shadows and color bleeding, where light form colored objects “bleeds” onto nearby surfaces.
In practice, radiosity and raytracing are often used in combination. On this basis, impressive and photorealistic renderings can be created.
The most widely used rendering engines.
Althrough rendering is based on incredibly sophisticated calculations, today`s software offers easy-to-understand parameters. On this basis a user does not have to deal with the underlying mathematics to achieve photorealistic results. A render engine is included in every 3D software package, and most of them contain material and lighting packages that allow impressive photorealistic values to be achieved.
Mental Ray (Autodesk Maya) is incredibly versatile, relatively fast and probably the best renderer for character images that require underground scattering. Mental Ray uses a combination of raytracing and global illumination (radiosity).
V-Ray, on the other hand, is typically used with 3ds Max. This combination is absolutely unrivaled for architectural visualizations and environmental renderings. The main advantages of V-Ray over the alternatives are the lighting tools and the extensive material library for arch-viz.
This was just a brief overview of the basics of rendering. It`s technical topic, but it can be very interesting to take a colser look at some of the common techniques.
Thank you very much for reading.