Abstract: The CAI system is developed to check the wrong in the computer-made exercises based on the AutoCAD software and its ObjectARX reactor mechanism. The system is composed of four modules including exercise selection, initiation, monitoring and verifying. When students make exercises in the AutoCAD environment, the system will carry on the real-time surveillance for drawing process to give the feedback information and the corresponding prompts after automatic correcting. Because of the integration of exercise making, correcting, wrong revising three processes, this CAI system can help students to learn and practice for engineering drawing efficiently and independently.

Key words: engineering graphics, marking system, graphic data, exercises