Abstract:
In Descriptive Geometry, it is noticed that when it comes about to the Methods of the Descriptive Geometry, the first theme that raises problems to the students is understandinghow to determine the true lengthof a line segmentusing the methods of replacingthe projection planes. Starting from the problems raised by the students, the authors have created a three-dimensional graphic model to help them understand how to determine the true lengthof a straight segment using the vertical projection plan change method