CAD (Computer Aided Design) technology is now crucial for every division of modern industry, from a viewpoint of higher productivity and better products. As technologies advance, the amount of information and knowledge that engineers have to deal with is constantly increasing. This results in seeking more advanced computer technology to achieve higher functionalities, flexibility, and efficient performance of the CAD systems. Knowledge engineering, or more broadly artificial intelligence, is considered a primary candidate technology to build a new generation of CAD systems. Since design is a very intellectual human activity, this approach seems to make sense. The ideas of intelligent CAD systems (ICAD) are now increasingly discussed everywhere. We can observe many conferences and workshops reporting a number of research efforts on this particular subject. Researchers are coming from computer science, artificial intelligence, mechanical engineering, electronic engineering, civil engineering, architectural science, control engineering, etc. But, still we cannot see the direction of this concept, or at least, there is no widely accepted concept of ICAD. What can designers expect from these future generation CAD systems? In which direction must developers proceed? The situation is somewhat confusing.