In this paper, we present an algorithm of modeling a solid object by defining enlarged-surfaces sequentially in Boundary representation (B-rep) solid models. We describe how our approach can solve current problems of blending in solid models such as terminating-edge-blends, overlap-blends and global-blends. Our approach is based on a simple and robust surface modeling method and its application to B-rep solid models. We also present a novel rule for B-rep solid models in order to include surface modeling methods. We illustrate how our approach overcomes problems of blending cases.

We present a general method for automatically reconstructing a network of B-spline patches based on the Doo-Sabin subdivision surface. This method consists of two parts, surface fitting and surface construction. In surface fitting, mesh simplification based on QEM (Quadric Error Metrics) is used and a control mesh that approximates a Doo-Sabin subdivision surface is constructed. In surface construction, we define a B-spline surface using a surface spline method; and a constructed network of B-spline patches is guaranteed G/sup 1/ continuous. In addition, this method has the advantage of enabling the user to select detail levels of the control mesh by utilizing a mesh simplification process.

The objective of this research is to apply the subdivision surface for surface fitting problems when generating surfaces from data points or polyhedral models. The basic idea is to use the subdivision limit position (SLP) to adapt the control mesh of the subdivision surface to the data points. This method is not a time consuming process involving global optimization. It does, however, fail to capture local characteristics of data points. Consequently, the proposed method is not suitable for generating a surface that precisely interpolates the data points, but it will be useful for quickly generating a surface that captures the overall shape constituted by the data points. A prototype system hers been developed to demonstrate several examples for purposes of evaluating the proposed method.

An algorithm for simulating a simultaneous collision impulse with friction working at multiple collision points between three dimensional rigid bodies is described. The authors also state that lasting collisions at small intervals will occur under some dynamic conditions and cause a decline in the simulation speed, and the method for avoiding this phenomenon is described.

The paper presents a method to render objects which consist of numerous small elements such as fur and leaves. The method visualizes both an effect under the pixel size such as the dark shade of fur toward viewers and an effect over the pixel size such as the shape of fur at contours. As for the effect under the pixel size, the intensity is computed based on the microstructure such as shadows by adjacent fur. After the intensity is computed, the shape of each element is generated by sweeping a two dimensional color element and applying transparency filters. Since shape generation is a post process, parameters such as length, width, curvature and color of small elements can be modified without repeating the intensity computation. It is useful for interactive design. The method is especially suitable to create still images because it is intrinsically two dimensional and screen resolution dependent. However techniques to keep three dimensional consistency and avoid problems of discreteness are taken into account for animation.

We propose a 3D mesh dragging method useful for intuitive, efficient geometric modeling of free form polygonal models. With our method, the user can drag a part of a triangular mesh and change its position and orientation. This method is based on an adaptive remeshing procedure which evaluates the deformation of faces by dragging and properly modifies them by deleting or splitting with local topological operations. Therefore the mesh is automatically adjusted for dragging, and irregularity caused by dragging onto the mesh is no longer a concern. In addition, this method is local to the dragged portion, so its computation is efficient. We describe our adaptive remeshing method and demonstrate some dragging examples.

Recently, animations with deforming objects are frequently used in various computer graphics applications. Metamorphosis (or morphing) of three dimensional objects can realize a shape transformation between two or more existing objects. We present a new algorithm for 3D geometric metamorphosis between two objects based on the harmonic map. Our algorithm is applicable for arbitrary polyhedra that are homeomorphic to the three dimensional sphere or the two dimensional disk. In our algorithm, each of the two 3D objects is first embedded to the circular disk on the plane. This embedded model has the same graph structure as its 3D objects. By overlapping those two embedded models, we can establish a correspondence between the two objects. Using this correspondence, intermediate objects between two objects are easily generated. The user only specifies a boundary loop on an object and a vertex on that boundary which control the interpolation.

A new method for analyzing position uncertainties of two parts in an assembly is proposed if certain shape variations of individual parts are allowed by tolerances. Assembled parts are considered to satisfy three conditions relating to their positions, which are nonpenetration condition, contact condition of mating faces, and optimization condition concerning their assembling method. Proposed method achieves the analysis by computing a variation bound of the configuration of the toleranced parts if nonnominal parts allowed by tolerances satisfy the positioning conditions. An experimental program for computing a variation bound is implemented and demonstrated. This program is applicable to 2D polygon models of machine parts, for example sections of polyhedron parts in an assembly.

A new algorithm for positioning two nonnominal parts in an assembly is proposed. Part positions are determined by optimizing a certain objective function within the feasible configuration space in which the parts do not collide. This algorithm is applicable to 2D polygon models of machine parts, for example sections of polyhedron parts in an assembly. Since manufacturing variations in part geometries are relatively small in comparison with the nominal geometry, the requisite translations and rotations for positioning the parts are small. Based on this characteristic of the part positioning problem, "bounding polygon" and "bounded polygon" based algorithm is developed for hierarchically approximating the configuration space. The efficient search of the optimum solution of the objective function is realized by using the hierarchical structure of the space. The algorithm is implemented and examples are shown.

Abstract This paper presents a systematic scheme for controlling the local behaviour of C2 interpolating curves, based on the cubic B2‐splines and the quartic S‐splines. Both splines have an additional control point obtained by knot‐ insertion or degree‐elevation in each span of the conventional uniform cubic interpolating B‐splines. The shape designer can choose the desired range of locality for each span and get the corresponding additional control point as a barycentric combination of interpolation points within the range, without solving any variational problem and simultaneous equations. The scheme is consistent over the entire curve subject to some typical end conditions. The class of the curves derived includes the conventional cubic interpolating B‐splines. Examples demonstrate the behaviour of the new interpolating curves and the capability of the scheme.

Abstract This paper presents an animation technique of collision response for deformable models defined as a spring‐mass‐damper system. Our approach is to calculate impulsive forces to prevent penetration of colliding objects by means of Hertz's contact theory. With this theory, contact duration and deformation in collision are obtained according to physical properties such as mass and elasticity. Animators, therefore, can represent the differences between materials such as rubber and steel in the sequence of collision animations with a few intuitive physical parameters. We also describe a deformation mapping technique which reduces the computational time of dynamic analysis and realizes the effect of global deformation.

and the presence of calmodulin (CaM) leads to the activation of calcineurin (CaN), a protein with serine-threonine phosphatase activity. The signaling pathway linked with CaN and transcription factors like the nuclear factor of activated T cells (NFAT) is essential for skeletal muscle development and reprogramming of fast-twitch to slow-twitch fibers. CaN activation may promote metabolic adaptations in muscle cells, resulting in better insulin-stimulated glucose transport. The molecular mechanisms underlying the altered insulin response remain unclear. The role of the CaN/NFAT pathway in regulating skeletal muscle hypertrophy is better described than its involvement in the pathogenesis of insulin resistance. Thus, there are opportunities for future research in that field. This review presents the role of CaN/NFAT signaling and suggests the relationship with insulin-resistant muscles.

This paper describes an interactive rendering technique for giving an impression of 3-D shapes. The following points are discussed : 1) The classification of continuous tone patterns 2) Methods of drawing pictures to enhance 3-D shapes 3) Rules of rendering for the representation of 3-D shapes. The following results are obtained: The use of the rendering rules and CARP facilitates the clear representation of these characteristics and is proved to be effective in creating a picture in which the shapes of bodies are clearly defined,

In the paper the design process is analysed and a new model of the design process which is usefull in CAD is explained. At working a construction with the computer we have to consider the function and form. The function defines the capacity of the construction and the usefulness dependet on the connection machine-nature. With the form we define the possibility of manufacturing and usefulness dependet on the connection man-machine, For a successful working of the function and the form we use geometrical modelling and word processing, The interaction between man-computer can the most easily be done with sketching (form) and speech (words). In the paper the data input with sketching is explained using keyboard instead of speech. In the appendix an example of working the construction by our method is presented.

We propose a unified method of generating a wide range of three dimensional objects from polyhedra to solids with free-form surfaces. Modeling systems for polyhedra and systems for free-form surfaces have been developed independently in the past because of the difference in their underlying theory and practices. However, this is not desirable for a designer. So in this paper, we have shown a method in which a wide range of shapes are generated in one system by using local modifications. Local modifications are procedures used to change the shape of solids locally. The construction and the modification of three dimensional shapes by these procedures are natural and easy for a designer in many cases. The implementation of these procedures in a computer is easy and their execution does not require much time.