ObjectARX is a development technology of AutoCAD based on MFC. The developed ARX program can do the job like finishing the drawing automatically and creating a swept-solid modeling. The general modeling software, such as Pro/Engineer, can not create a swept-solid with 3D solid or surface. The profiles of the parts may be expressed by some equations like spur gear, while others may be not like bevel gear and space cam. In this paper, a solution for the development of part without accurate profile equation by using the ARX technology is investigated. With the help of the ARX in AutoCAD, the related entities in the database to do some Boolean operations are manipulated and the swept modeling is created. As the examples, the 3D solid model of a gear and a cam is built to demonstrate the use of the method. The limitation of the method is also discussed.