||"1. The exception proves the rule; Knowledge Based Automatic Concrete DesignFrom the early 80 till the second half of 1990 the software Matrix developed for structural engineers was based on the MsDOS platform. In those years the codechecking distinguished itself by an extremely enforced integrated approach. A complete structural design including the generation of drawings could be realized at once, with one press on the button. In this concept there was no room for the intervening interaction of civil engineers. They had little or no influence on unforeseen situations or shortcomings in the automatic analysis of boundary conditions or the automatic design.The fact that we were secured of the cooperation of civil engineers (experts) concerning improvements makes it possible for us to make our knowledge based system even more complete.2. The exception becomes the rule; Interactive Concrete EngineeringA disadvantage of a full automatic structural design is the existence of exceptional cases. Every case needs to be programmed which leads to a huge programming effort. In order to complete the last 20% you need a programming effort of 80% of the total period. Another disadvantage is the different approach by the government for using software for code checking. The new Windows software is based on a structure very close related to the level of code checking. All the relevant parameters can be manipulated. The link to the code is absolutely clear by the visualization of the applied code article as well as the provided value and the required value.3. The 80-20 rule; The concept of hierarchical levels80% of his time a civil engineer is using only 20% of the functionality of his software for structural analysis. A program doesn’t need to be too complex for daily use. When you think in different levels you can manage the 80% for daily use, as well as the 20% for the advanced topics in 1 program.The computer, using generative processes, without intervening interactions can work out 80% of all calculations. When you think in levels it is possible to work out the other 20% by the same program.4. Ruling by exception; Computer Aided Learning system10 years ago the TU-Delft developed a CAD exercise. During this period more than 1500 students used these exercises for their training. This CAD exercise was developed in order to support students in dimensioning, analyzing and detailing concrete structures, after the introductory lecture in designing and constructing concrete in their third academic year. EUROCADCRETE is a continuation of the CAD exercise mentioned above and is based on the educational version of MatrixFrame 2D-Frame and on the experience of the TU-Delft during the lessons of the CAD Concrete exercise. Students at home can define the structural analysis part of the exercise. Then the prepared job can be worked out according to the EuroCode in the EUROCADCRETE environment. The last part of the exercise gives the student the opportunity to perform parametric studies. By means of exercises and by providing interactive tools students gain a clear insight in the nature of reinforced concrete, which is the aim of this job. A learning system like EUROCADCRETE is a combination of, on the one side, a Graphical User Interface based on the lowest level, and a check mechanism and parametric study on the other side, which is based on the advanced level within the concept of hierarchical levels."