This paper proposes the concept of Tool-Based Direct Deformation Method (TB-DDM) which supports networked CAD (Computer Aided Design) systems with virtual reality technologies. TB-DDM allows designers to sculpt free forms directly with tools; each tool has its deforming characteristics, such as, the area and the shape of deformation. TB-DDM's direct deformation interface is independent of form representations because the system automatically calculates appropriate deformation according to its form representation when a tool pushes" a form. The deformation with TB-DDM is concisely described by the initial shape, types of tools, and thier loci; the description enables cooperative CAD systems with narrow bandwidth network to share design process rapidly and to distribute computational load.