The current status of 3D variant design for mechanical component was analyzed

and the exiting disadvantages were pointed out.Four-level 3D variant design including feature

component

assembly

and product was researched.According to the characteristics of hoisting machinery metal structural

the 3D variant design of certain mechanical product by building master model and configurable sketch was presented.The automatic adjustment of engineering drawing based on topology constraint

dimension constraint and engineering constraint has been achieved

which can automatically adjust all the engineering information in associated 2D drawing.Under the support of these technologies

a rapid design system based on 3D CAD platform was developed

which has been carried out successfully in four heavy machinery group companies.The research is significant for promoting the rapid design of the other mechanical product series.