Abstract
We have developed a computer assisted instruction system that generates the 3-dimentional (3-D) model from the projection views of the object in order to enable students to learn machine drawing without the help of teachers. In this study, the function of overlaying the projection views on the 3-D model was proposed for the purpose of assisting to understand the correspondence of the projection views to the 3-D model. Each vertex of the projection views are linked to the 3-D model with dotted lines so that one can verify the validity of existence of the vertexes in the 3-D model and can find the portions and the contents of the errors included in the projection views. The correspondence of the lines between the projection views and the 3-D model can be also found by moving the overlaid projection views along those normal directions. By conducting trial use, it was demonstrated that one can specify errors in projection views by means of the proposed function.
