[in Japanese]

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The period in which a 3D model is generated using digital engineering needs to be shortened. Therefore, we developed a modeling system of fluid machinery that enables generating a 3D model by inputting design parameters. Using this system, we were able to generate 3D models similar to existing ones quickly.

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A solid model representing product requires fillet or blend process, which rounds a specified edge or vertex, in order to make a production model for manufacturing purpose such as mould die model. Current major solid model CAD systems are based on boundary-representation (B-rep) and they represent faces using trimmed free-form surfaces. However, their models have problems in blend process to become unstable at edges of narrow faces or at both ends of such faces. We propose that a new boundary-representation structures and new blend algorithms which enable blend process to become robust. In this report, we propose a procedural blend-representation that surfaces are not represented explicitly.

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We have developed a method to generate a NURBS curve based on line segments. A NURBS curve is generated by giving the positions and the directions on the concatenated line segments. According to the number of line segments and control points of the NURBS curve, the system to be solved may be underdetermined or overdetermined. The methods to solve these systems are shown. In addition to these, a NURBS curve generation example based on the line segments is shown.

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[in Japanese]

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After reviewing different approaches, a new algorithm is presented for fairing B-spline curves and surfaces. It is based on a novel fairness measure, which is derived from a notion called ″target curvature″. The target curvature is computed from the not-yet-faired curve or surface automatically, but with optional user-interaction to make it flexible. The method itself is parameter invariant and local. We introduce two implementations, a slower, iterative method emphasizing locality and a faster algorithm involving discrete integration and fitting. The results are illustrated by a few examples.

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Many methods have already been proposed to control the curvature distribution of curves, but most of them are for planar curves. This research proposes a new scheme for controlling curvature distribution of planar and space curves, based on discrete curves. Discrete curves, such as discrete Clothoid, have an ideal curvature distribution, because discrete geometry models have a high degree of freedom. For application to practical CAD/CAM, a parametric curve with a controlled curvature distribution can be generated based on a discrete curve with an almost ideal curvature distribution. A G² curve consisting of quintic Bezier curves has been generated by the energy minimization method. The curvature distribution of the result curve by using the method of this paper shows the smooth change throughout the curve. Smoothing a result curve can be done by adjusting its connection points simultaneously with the curve generation.

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When an object is scanned, its mesh model inevitably contains noise. Therefore, smoothing method is required to obtain a fair surface. We have proposed a mesh smoothing method that consists of feature extraction process and anisotropic diffusion flow. In our method, especially feature extraction plays a significant role to produce a well-smoothed mesh, therefore, we have engaged in an improvement of feature extraction. In this study, we present a result of a modification of local sharpness function and a method to determine standard deviations which were use-defined values. The example on the Fandisk model show that this improvement yields a better result of feature extraction.

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This paper presents a method for computing distance fields from large volume models. Conventional methods have strict limit on the size of memory space. This is because all of volume models must be allocated on the random access memory (RAM) to compute distance fields. We resolve this problem by out-of-core strategy. Our algorithm starts from decomposing volume models into small regions called cluster. Then, Distance fields are computed by Local Distance Transform (LDT) and Inter-cluster propagation (ICP). LDT computes distance transform for each cluster. Since LDT is independent, other clusters can be saved on the storage. ICP propagates distance on the boundary of the cluster to neighbor clusters to remove inconsistency of distance fields. In addition, we also propose an efficient ordering algorithm based on propagated distance to reduce LDT and ICP. This paper also demonstrates the results of distance transform from volume models with over billion cells.

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This paper presents methods for calculating geodesic distance and k-means clustering based on out-of-core strategy. These methods are application of distance transform based on out-of-core strategy. By using these methods, we can calculating geodesic distance and k-means clustering for large data, it couldn′t be treated for limit of RAM.

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Recently, mesh deformation techniques have been intensively studied. Such methods preserve differential properties of the original meshes as possible, fulfilling given constraints. We propose a method of the mesh deformation with kinematic constraints. In the proposed method, handles of the deformation are treated as rigid bodies, and the relation of the handles are defined by kinematic models. The kinematic models enable a motion of a handle to propagete to another one, and the motions of the handles realize the deformation.

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This paper proposes a framework for interactively deforming assembly models with multiple disconnected meshes. The method combines surface-based and volume-based deformation. Each model is encoded using differential properties for the surface-based deformation and mean value coordinates for the volume-based deformation. Since the deformation methods are interrelated through linear systems, the deformation of one model can be interactively propagated to the other models. The implemented system can achieve a real-time response for the deformation of assembly models.

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This paper proposes generation method of surface texture using stitching. Using measured data, it resolves the issue in which texture can′t depict refined shapes finely. Multiple narrow domain surface textures that measured with microscope-type surface profiling instruments change a large field of surface textures using stitching. Based on this texture, texture synthesis by patch-based sampling makes an arbitrary area. As a result, textures created with the system are more refined than conventional textures.

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[in Japanese]

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This paper describes a method for determining the similarity of part features of 3D objects. The method consists of three procedures: (1) extract features from a solid model and creates dependency graph, (2) compare the dependency graph of two solids, (3) determine the similarity of part features. The form subdivided partially can also be compared by this technique.

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To realize efficient and robust mesh generation for finite element analysis is still remained as a challenge in CAE. In this paper, we propose a tetrahedral mesh modeling method for CAE. First, Boolean operations of the mesh models are achieved by using a mesh combining method based on connector insertion and mesh simplification. Then, mesh-based geometric modeling method is proposed using Boolean operations and multiresolution technique for finite element analysis.

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When we use volumetric models in digital engineering like CAD/CAM/CAE, we ordinary polygonize them by contouring the entire objects ″or″ extracting medial surfaces, but it's desirable to apply different modeling approach according to the shape of each parts. In this paper, we propose a new modeling method which is based on decomposition by dimensionality, which is composed of solid, plane and wire. And we also propose a new skeletonization method affecting the final results of this method, which can extract simpler skeletons with fewer branches from even noisy data than before.

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[in Japanese]

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As-built 3D models are useful for simulating maintenance processes of manufacturing facilities. So far, several 3D scanners have been developed to measure large plants, but they produce hundreds of millions of 3D points with relatively large position errors and outliers, which are difficult to process by existing reverse engineering techniques. In this paper, we propose methods for segmenting and calculating surfaces using outliers.

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CAM software develop making processing thing of complex shape in wide area.CL data is computed each same shape paying attention to rule of surface texture.This corresponds to surface texture while moving and turning mapping.CL data request that it does not calculate whole surface.As a result,I obtain a prospect good accuracy processing a texture with regular pattern.

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[in Japanese]

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The 3-D Computer-Aided Design systems have the fabulous form definition function which realized great contribution in the conceptual phase of the design process by promoting of streamlining. However, when the user tries to develop his ideas by using the 3-D Computer-Aided Design systems in the early stage of the design process, his ideas may be disturbed or limited because the 3-D Computer-Aided Design systems are built on the accurate form definition. Indeed, the designers usually convert their ideas into tangible forms by drawing rough sketches. This paper deals with an interface system which is effective in the conceptual phase of the design process. The interface system recognizes primitives: cylinders, cones, spheres, and cuboids from sketches of functional components drawn by a designer and constructs 3-D models. The algorithm of the system is so built as not to obstruct thinking design of the designer. The results show that the recognition of the primitives has been done correctly, and the implementation of the system in a 3-D Computer-Aided Design system can help the designers to shorten the time of designing.

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[in Japanese]

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[in Japanese]

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In order to respond to consumer needs, it is necessary to develop the product of a high function for a short period of time, and increase in efficiency of development is desired. However, in the product development environment which uses a present three dimensional CAD system, since the holding-ness and the operativity of a handy information device cannot be evaluated correctly, a majority of trial productions, evaluations, and corrections need to be repeated, and it prevents from efficient product development. So, the goal of this research is to realize an augmented reality system for efficient product development of a handy information device. Using this system, the user grips the tangible device which tactually displays the diagrammic shape of the handy information device under designing. At the same time, the user watches the visual seen which is generated from the real image of the hand of griping the interface is superimposed on the minute shading image from the 3D-CAD model synchronized with the device. Then the user is able to feel to directly operate the device in designing. The configuration of the sytem is decsribed in this reoprt.

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In the first report of this research, we proposed a virtual clay modeling, and discussed the effectiveness about the design support using existing resources (3D-models). In this method, we use the topological deformation of TGM for cutting and joining arbitrary triangular meshes, and TGM is directly used as a deformation structure of the target mesh. In this report, we propose an extended deformation method. In this method, we applied t-FFD to the deformation interfaces, and TGM is used for the deformation structure of the control mesh. A target mesh is deformed more efficiently and stably than the previous method.

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Shape deformation by using Finite Element Method outputs accurate results, but this method needs much calculation, and requires various ideas, for real-time processing. Our method using tensegric model and t-FFD is effective to simulate a shape deformation of complicated models with an interactive speed. This paper proposes a method to constrain the deformation of the tensegric model, as if it is tightened by a wire-like object. When tensegric model is deformed, the wire-like constraint tries to keep its length, and affects the model with pseudo forces. This method is expected to simulate the shape deformation of a human body constrained by a wearing corset.

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In our research, to achieve effective product design, we have proposed a parametric deformation method for mesh models. In this paper, we propose a parametric deformation method which user can automatically generate the handle suitable for the intended deformation and shape using a set of polytopes. With our method, the variety of deformation increases and user can control shape of the deformed mesh model such as a change of distance between two parallel planes with constraints for preserving planes.

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In order to create an aesthetic surface, it is essentially important to consider the curvature variation. We have developed a method to generate a surface using a curve-ruler that moves along two guide curves. Curve-rulers have a monotonous curvature variation, therefore, the ruler-suraface is guaranteed to have good quality. In this study, we re-formulate the expression of the ruler-suface to be parametric form and introduce another type of constraint condition, that is, the tangent of the ruler-surafece on the guide curve can be specified by designer. Examples show that the presented method works well. In addition to this, we also present a methodology for generating guide curves to create high quality surface. With this method designer only have to input some control points of the guide curve to generate an aesthetic surface.

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This paper deals with a system to design product surface texture which has important roles to give luxury to a product and to keep product surfaces. On using the system, impression of the designed texture can be quantitatively controlled. ″Fractal″ and ″1/f Fluctuation″ which are the laws existing in nature are utilized for the quantitative control of impression. A basic form of texture is constructed as ″Fractal″, and ″1/f Fluctuation″ is added for the basic texture to give a natural impression. A variety of textures are generated from different patterns of parameters which represent ″Fractal″ and ″1/f Fluctuation″.

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[in Japanese]

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Today, many people buy their shoes at internet (virtual) shops instead of going to real shops. However, it is a problem that the shoes do not always fit their feet, because shoe makers design them based on standard foot models. This report presents a technique to easily generate a 3D Foot Shape Model for an individual person by transforming a generic model to it with use of the information of feature points obtained from the pictures of four views. As a basic transforming technique, we use the GFFD (Generalized Free-Form Deformation) method that we had originally developed.

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In this study, we propose a technique to draw grass models as many as possible in real time. We reduce the number of polygons to draw using LOD (Level of Detail). LOD is a technique to switch the models with simplified ones like billboards. We can switch them with less detailed but more efficient models because the grass models are drawn in small size on monitor and it is not clear to recognize their structures on the long distance from the viewpoint. In addition, we apply the wind blow animation to the grass models. Therefore, we can draw the realistic grass field that has enough detail for background, even though we use simplified models to decrease the rendering costs.

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[in Japanese]

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In our previous researches, the coated-cemented-carbide tool is found so effective for the ultra-precision cutting of stainless steels and titanium metals. The surface roughness formed in ultra-precision cutting of titanium alloys is below 200 nm(Rz) until the cutting length of 2,000 m. However it is not adequate for producing the ultra-precision components. It is considered that the tool wear is caused by the cutting temperature rise due to the contact of tool to workpiece at high speed cutting. In order to improve the tool life, in the research, the effect of low cutting speed on ultra-precision cutting of titanium alloy with coated-cemented-carbide tool is examined. Using the extremely low cutting speed below 1 m/min and depth of cut of 5 micro-meters, the surface roughness improves remarkably and attains below 84 nm(Rz) at cutting length of L = 212 m and keeps below 100 nm(Rz) until cutting length of 4,000 m and below 200 nm(Rz) until cutting length of 10,000 m.

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In our previous researches, the smooth wear surface of coated-cemented-carbide tool is found roughly to influence effectively on the ultra-precision face-turning of stainless steel. In the research, the changes of the wear surface roughness of cutting edge and the face-turned surface roughness of stainless steel with face-turning process are examined. In the basis of the results, the relationship between the wear surface roughness and the face-turned surface roughness is investigated and found to be closely correlative. The surface roughness of ultra-precision turned stainless steel SUS316 becomes below 50nm(Rz) until the cutting length of 1,000m and below 100nm(Rz) until the cutting length of 1500m, respectively.

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It is known to finish difficult the aluminum alloy to high smoothness surface by grinding because the alloy adheres easy to cutting edge. The possibility of ultra-smoothness grinding of aluminum alloy with newly developed vertical ultra-smoothness grinding method, in the research, is investigated using grinding fluid including extreme pressure additives having the repressive effect of adhesion. By selecting the suitable grinding conditions, the surface roughness is found to attain below 50nm(Rz).

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High smoothness grinding of carbon steel has been increasingly becoming important. Finished carbon steel surface are created using cubic boron nitride tool. We used the resinoid bonded wheel and examined the effect of the grinding fluid on the grinding wheel face and the finished surface. Two type of grinding fluids were examined : the semi-emulsion type including the extreme pressure additives and the synthetic emulsion type that has conventionally been supplied for smoothness grinding finishing. From the results it is found that the surface roughness of carbon steel becomes 0.5 μm(Rz) by using the semi-emulsion type including the extreme pressure additives. The critical total wheel-workpiece contact number using the synthetic emulsion type becomes more than using the semi-emulsion type including the extreme pressure additives.

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[in Japanese]

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Polishing characteristics of glass type of magnetic disk substrate, in the previous researches, is investigated. To clear the polishing mechanism, in the present research, the polishing forces for the various kinds of conditions are examined. On the basis of the results, the influence of polishing pressure, polishing speed and content of abrasives on polishing force is investigated. Polishing force increases with the increase of polishing pressure and content of abrasives, while it decreases with the increase of polishing speed.

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Precise surface preparation techniques to make atomically flat and defect-free SiC surfaces are strongly demanded in the next-generation semiconductor technology. However, effective technique does not exist particularly for surface smoothing. This research investigates the possibility of flattening silicon carbide (SiC) surface by a novel abrasive-free planarization method utilizing iron (Fe) catalytic reaction. To demonstrate the probability of flattening SiC surface, we conducted the experiment which rubs SiC surface softly with an iron wire selected as a catalyst under the hydrogen peroxide solution. After that, the surface on SiC substrate, where an iron wire contacted, was observed and evaluated in detail. The obtained results show that a hard SiC surface in contact with an iron wire can be removed markedly and the obtained surface has atomic-level flatness along the rubbing direction.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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We aim to realize a deskwork support system that hands over a necessary object to a worker without any explicit instructions. In this study, we propose a method to predict the target object which the worker wants to get. Using gaze information as well as hand movements, the system can predict the target object appropriately at a very early stage A description of the experimental results demonstrates the usefulness of the method proposed here.

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[in Japanese]

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[in Japanese]

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When we record the contents of conversations in a working space, there seems to be a problem that the other people are not able to identify the object which is represented by a deictic representation. In this paper, we propose a method to identify such objects. The proposed method estimates the object that is referenced by a pronoun in conversations, by using the distance information which pronouns have, and the position and orientation data of the speaker. We also developed an user interface using three-dimensional measurement of six markers, for the measurement of the speaker's head position and orientaion. Then we developed system for the proposed method.

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We aim to find new markets by Nano EDM,Nano machine and Hybrid-Wire EDM by developing the element technology of linear motor,motion controler,etc.

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