Rendering in computer graphics

Rendering phase is where geometric models, light effects and mathematically defined animation paths are turned into realities. Trust me it is extremely difficult to create computer graphics images that look realistic.

I am going to list the major milestones in computer graphics rendering below.
1. Wireframe rendering: The simple vector graphics represention of polylines or any surface geometry.
2. Hidden line rendering: Shows only portions of the surface that face you directly.
3. Surface Shading: Flat shading of one color per polygon. No interpolation at all.
4. Gouraud Rendering: Interpolates each pixel value from each vertex illumination value.
5. Phong shading: Uses the surface normal information when interpolating the vertext values.
6. Ray tracing: Advanced lighting techniques and reflection, refraction and specular, diffuse, emission, ambient kinda values are taken into consideration.
7. Radiosity: A good compliment to ray tracing technique. It calculates lighting based on global illumination techniques as well.

Bump mapping, displacement mapping and texture mapping add rendering details to existing geomety. It is the technique of creating surface detail through surface normal perturbation. The shader function is defined by 8-bit data. It only perturbs surface normals and does not directly affect underlying geometry. Displacement mapping does afffect the underlying geometry.

Autodesk's product Maya has excellent rendering tools. They have thousands of different shaders that can be defined using various parameters.