An approach towards offsetting of object in nonmanifold 3-D geometric modeling

In the areas of rapid prototyping and Reverse Engineering, non-manifold offsetting is the process by which an arbitrary shape of a 3D model can be formed. One can change the perimeter of regular and irregular triangular mesh (T-mesh) surface. In addition, it can change irregular (raw) surface into a regular (planner) surface. In general, segmentation is useful before offsetting takes place. This paper introduces an algorithm, which performs offsetting operations in non-manifold geometric modeling. This can be applied to not only wireframe, sheets and solids but also combinations of them in one integrated modeling environment. The mathematical definitions and properties of non-manifold offsetting operations have been discussed here. In addition, variations of the offset algorithm for wire frames and sheets also have been discussed. The offset algorithms have been implemented in many shapes, which is a non-manifold modeler based on the Partial Entity Data Structure.