Norio Okino

Extended Depth-Buffer Algorithms for Hidden-Surface Visualization

Users of interactive CAD systems who are trying to cope with the hidden-surface visualization problem will want to investigate this new algorithm.

RESEARCH ON 3-D GEOMETRIC MODELING BY SWEEP PRIMITIVES

This paper proposes a new modeling method for not only ordinary mechanical part geometry but also special ones, such as a coil or a bend etc. The new method is called “Sweep Primitives”, because of constructing a volumetric primitives by sweep operation and combining these primitives by set operation. How to develop a sweep primitive is as follows, namely, named “secondary pattern” as spine of sweeping/trajectory curve and “primary pattern” as being the sweeped pattern along the secondary pattern. And these primary and secondary patterns are represented by “language” then we can use these with other volumetric primitives. As a result of developing and adapting this sweep primitive method, most of the mechanical part geometries are easily modeled with less effort.

O/O (Object and Operation) Dualism for CAD/CAM Software Architecture

Summary Not a computer oriented but an application oriented software architecture is strongly required by engineers who are involved in information processing in the design and manufacturing field. This paper describes a conceptual approach for developing CAD/CAM oriented software architecture based on dualism of Object and Operation on the hypothesis that information processing in design and manufacturing consists of interaction between Object and Operation. After abstracting Object and Operation, the 0/0 dualistic software structure, including conceptions of 0/0 frame, Object cell and Operation cell is introduced with graphic description rules. This is applied to the following problems as examples. (1) Modelling problems; Solid model and models for drawing, design, NC and assembly are defined by the 0/0 dualistic structure. (2) Programming problems; After describing a methodology of programming by the 0/0 dualistic structure with graphic programming, examples of design process, process planning, NC command generation and robot operation planning are mentioned. (3) CAD/CAM system design; This section presents a system design for CAD/CAM at which the discussion by the 0/0 dualism arrives. And also, it is shown that the proposed system has the possibility to grow into an intelligent system.

Theories for graphics processors in TIPS-1

Abstract This paper describes the theoretical aspects of graphics processors in CAD/CAM system TIPS-1. As one of the man-machine interfaces in the CAD/CAM field, computer graphics plays an important role. And this field, computer graphics involves not only image processing with shaded pictures produced by raster scan displays but also sectional and/or perspective view drawing picture by line drawing display. By using TIPS-1 graphics processors, we can get both raster scan and line drawing pictures for the same of modeled 3-D geometry. The following items are considered as the necessary conditions for developing graphics processors. • • To develop geometric modeling theory. • • To develop generative geometry pattern processing theory. • • To implement problem-oriented graphics routines based on above conditions. How to complete these conditions is described with several figures and graphic outputs.

Advanced 3-D shape description methods in TIPS-1

Abstract The special features of shape or geometry description and numerical geometry processing theory adopted in the TIPS-1 system are described with some graphical outputs as the results. For the description of any kind of 3-D shape, TIPS-1 has the following methods: Set operation by 3-D primitive blocks, three dimensional sweep operation of 2-D primitives, Coons interpolation for set of points, calling operation of SUB-ROUTINE type of formulas. For the numerical geometry processing theory, a Penalty Function as a space evaluator is shown.

Development of the 3-dimensional CAD system for injection mold design. (4th Report). Automatic generation of cavity and core.

Several useful functions for injection mold design are prepared for the system. In this paper, one of the most important functions, i. e., the function of automatic generation of cavity and core is discussed and the newly developed algorithm for the function is presented. And also, some examples which are gotten by the actually developed software are shown. The automatic generation of cavity and core is done using the user-defined geometric data such as product shape, blank shape, parting surfaces and shut-off surfaces.

A study on 3-D solid modeling of fillet volume by CSG representation. On the fillet of corner rounding.

This paper presents how to make a solid model of the fillet volume for rounding corners such as vertices or edges. In order to be able to handle the fillet volume in CSG representation for geometric modeling, Sweep Operation is applied to generate the fillet volume. The outline is described below : 2-D Fillet Pattern, Spine, Sweep Axis and the object which is constructed by cubic primitive solids, are given. Then the fillet pattern, defined on a sectional plane which is normal to the spine, is swept along the sweep axis. Swept Volume consists of a set of space points which are inside or on the fillet patterns from start to end of sweep. Fillet Volume is generated as a result of swept volume, and can be added to the object for modeling of final shape with corner rounding. The algorithm of this work has been implemented in the CAD/CAM system TIPS-1. According to experimental results, it is clear that the work is effective for geometric modeling of an object being constructed by cubic primitive solids and fillet volume.

NEW GEOMETRIC MODELLER TIPS/GS FOR GEOMETRIC SIMULATION

In spite of big expectation and long history, CAD/CAM systems based on solid modelling make slow progress. It would seem that something is wrong with the solid modelling technology. This paper describes how to open the way for advanced solid modeller. First, it is discussed what problems there are in present solid modellers. Second, some strategies to solve the problems are proposed and finally, development of TIPS/Geometric Simulator is described in which the proposed strategies are demonstrated. TIPS/GS is a new solid modeller which consists of assembly simulator with interactive input interface using shaded picture, engineering simulator, NC simulator and robot simulator.

CAMPS — Computer-aided manufacturing for punching-press and shearing

The realization of shearing process as computer-aided manufacturing has been difficult since an NC shearing machine appeared. This is due to the difficulty of making an automated plan for nesting, an allocation of materials required as users product to given blanks. If this problem is broken up, it becomes possible to develop an integrated software system for punching-press and shearing. In this paper, the software system is presented for computer-aided punching-press and shearing in a metal sheet production by applying a new nesting method to shear process planning and by developing an automated determination of punching-tool path. The developed system is named CAMPS (abbreviated Computer-Aided Manufacturing for Punching-press and Shearing).