6. Raytracing   

Raytracing produces photorealistic images BUT is very computationally expensive. It is explained here: 



       Introduction.  
       The Ray Tracing Technique  
       Reflection.  
       Transmission.  
       Intersection Tree Generation.  
       Shading Algorithm.  
       Object Representation.  
       Terminology.  
       Command Line Arguments  
       User Interface  
       3DDDA Techniques  
       General speeding up raytracing  
       Algorithm for 3DDDA
Images produced by raytracing are very realistic but not as accurate in terms of lighting as those produced by Radiosity techniques.