Updating 3D triangular mesh models based on locally added point clouds

Abstract

In a manufacturing area, design changes for an original surface model are frequently required: for example, when the physical parts are modified or when the parts are partially manufactured from analogous shapes. In this case, an efficient surface updating method by locally adding scan data for the modified area is highly desirable. For this purpose, this paper presents a new procedure to update an initial model that is composed of combinatorial triangular facets based on a set of locally added point data. Nowadays, many people are using surface models that are represented by triangular facets in reverse engineering, since it is fast and easy to create the triangular meshes directly from large amounts of point data. The initial surface model is first created from the initial point set by tight cocone, which is a water-tight surface reconstructor; and then the point cloud data for the updates is locally added onto the initial model maintaining the same coordinate system. In order to update the initial model, the special region on the initial surface that needs to be updated is recognized through the detection of the overlapping area between the initial model and the boundary of the newly added point cloud. After that, the initial surface model is eventually updated to the final output by replacing the recognized region with the newly added point cloud. The proposed method has been implemented and tested with several examples. This algorithm will be practically useful to modify the surface model with physical part changes and free-form surface design.