Hiroaki Chiyokura

UNDO and REDO Operations for Solid Modeling

This article describes a method of representing a solid design procss using a tree structure. This representation supposrts UNDO and REDO operations for regenerating any solid in a previous stage of the design. The implementations of invertible set operations is also given in detail.

Localized surface interpolation method for irregular meshes

A surface interpolation method for irregular meshes of curves is proposed. When a face in the mesh is interpolated, a surface patch on the face is individually generated from localized boundary information. The tangent planes of generated patches are continuous. This method employs an extended Bezier patch as a surface equation. The patch can be defined, specifying independently normal derivatives along the boundary curves. The total procedure of generating patches is simple and quick.

An Extended Rounding Operation for Modeling Solids with Free-Form Surfaces

An extended rounding operation can be an excellent tool for modeling solids with free-form surfaces. Using the rounding operation, the edges and vertices of a solid can be locally rounded, and those parts of the solid are changed to free-form surfaces. As a user, you put in information about edges that should be rounded and the radii of curves generated by the operation. This facility has been implemented in our solid modeling system, Desiqnbase.

A Method of Representing the Solid Design Process

Wish modeling systems were more user friendly? This one quickly regenerates a solid design from previous developmental stages to ease the usual trial-and-error procedurtes

A Representation of Solid Design Process Using Basic Operations

The importance of using solid modeling systems in the computer aided design of three-dimensional objects has been widely recognized. However, current solid modeling systems are not very easy-to-use for interactive geometric design. Therefore, we are proposing a method of representing solid design process in terms of a set of basic operations, which can be used to create userfriendly modeling systems.

A method to convert a Gregory patch and a rational boundary Gregory patch to a rational Be´zier patch and its applications

A Gregory patch and a rational boundary Gregory patch have characteristics such that any n-sided loop is interpolated smoothly and that many patches can be generated to connect smoothly with each other. However, since the mathematical form of these patches is different from conventional surface patches such as the Bezier patch, no algorithm was known to subdivide them. The subdivision algorithm that could be applied to other surface patches could not be applied to them.

An enhanced rounding operation between curved surfaces in solid modeling

This paper introduces a method using the rolling ball technique to generate geometrical and topological information to blend two surfaces in B-reps-based solid modeling systems. At first, a ball is positioned so that it touches both surfaces to be blended, and the trajectories of the tangent points of the ball and the surfaces are computed. Edges are generated on the surfaces along the trajectories, and are then joined by arcs to create the blending surfaces. The created surface depends on the shape of the surrounding edges, and is interpolated using rational boundary Gregory(RBG) patches. By using this method, blending surfaces can be connected smoothly, even at the corner of a solid. This method can also be applied to surface blends other than those using the rolling ball technique. Variable-radius blends which are essential in free-form surface design can also be generated using this method.

Invertible Set Operations for Solid Modeling

The paper describes a method of representing the solid design process using a tree data structure. Previous stages in the development of a design can be quickly regenerated by specifying nodes of this tree. A detailed description of the implementation of invertible set operations is also presented.

Boolean Operations of Solids with Free-From Surfarces Through Polyhedral Approximation

The paper describes a new implementation method for Boolean operations between solids with free-form surfaces. Boolean operations consist of two processes, topological modification and geometric modification which are performed separately in our method. This separation makes the Boolean operation process simple and robust. Surfaces contained in the final solid are interpolated by the repatching facility using Gregory patches.