Abstract: A method for reducing the complexity of a polygonal mesh representative of the surface of an object to be displayed such as for medical imaging purposes systematically removes features from the mesh and reconnects the modified mesh in such a way as to preserve the original shape and topology of the mesh. The procedure removes both vertices and polygons from a polygonal mesh either alone or in combination. In order to reduce the number of polygons in an object for which a mesh has been generated, the method of the present invention repeats the decimation process until a desired number of polygons is achieved.

Abstract: A graphic workstation converts a polygonal model generated with computer aided design (CAD) software or volumetric data into a more compact polygon strip list having multiple strip sublists. The strip list, in addition to being more compactly stored, is displayed much more rapidly than conventional polygonal models since much of the redundant redrawing is eliminated. Shared point of adjacent polygons are eliminated. The strip list consists of a number of strip lists, each list having vertices of a first, or initial, polygon and subsequent vertices defining remaining portions of polygons to be `built onto` the polygon strip in the strip direction. Since this method of model storage and display is much more efficient, less powerful graphic workstation could be implemented in place of more powerful graphics workstations; or alternatively, existing graphics workstation would become faster and have more free memory available for other functions.

Abstract: A method of determining surfaces of swept volumes, which defines a region reserved for the removal of an object, or the motion of an object, is determined employing implicit modeling. A definition of an object and the trajectory in which it is to be moved are provided to the swept surface display device. An implicit model is created by determining shortest distance from each voxel of a object volume to a surface point of the object. A workspace volume has voxels each initialized with distances which are much larger than any distance envisioned. The implicit model space voxels are transformed relative to the workspace voxels according to the trajectory at a time t. Workspace voxels are updated with corresponding implicit model space voxels when the value of the implicit model space voxel is lower than the workspace voxel value. The implicit model space voxels are transformed relative to the workspace voxels for another time t and the number of workspace voxels are again updated.

Abstract: A graphic technique, implemented on a graphics computer, for visualizing 3-D vector data uses a stream tube which is a tube-like structure having a cross section of an n-sided polygon. The stream tube follows the path of a streamline in the 3-D vector data. Data can be visualized by varying the shape and size of the polygon along the streamline to represent changes in normal and shear strain, rotation and velocity. Additional scalar functions are represented by coloring the sides of the stream tube.