Representation for three dimensional drawings based on digital product definition data practices

On the basis of the analysis of representation for two-dimensional drawings, the authors studied the basic forms of representation for three-dimensional drawings and the national standards regarding its newest criterions as well as requirement, and then presented a new Description of engineering drawing under the software circumstance of features modeling, which applied all kinds of representation methods for two-dimensional drawings under the manual drawing circumstance and introduced the new national standards to implement representation for three dimensional drawings. This method took well advantage of digital product definition data and enriched the means of representation for three dimensional drawings.