Subdivision methods are widely used for surface interpolation of a non-four-sided area. Using thi... more Subdivision methods are widely used for surface interpolation of a non-four-sided area. Using this method, smooth surface shape control of multiple surfaces is difficult. Therefore, we used the trim surface for interpolation of a concave area, but shape control of the trim surface was also difficult. In this research, the surface interpolation method of non-four-sided (over 4 sided) area uses a single NBG (NURBS Boundary Gregory) patch. Moreover we apply this method for concave areas and study the ability of interpolation. Interpolation of one-sided and two-sided concave shapes is also considered. As a result, one-sided concave area can be interpolated smoothly for complex cases. Two-sided cases need further study.
... Due to this, we consider additional arrangement for the point data. Gopi's algorithm [10... more ... Due to this, we consider additional arrangement for the point data. Gopi's algorithm [10, 11] uses influence sphere for the sampling criteria. Possible Delaunay neighbors of point p will lie inside this sphere. ... l l k ji, (5) ...
Ninth International Conference on Computer Aided Design and Computer Graphics (CAD-CG'05), 2005
In 3D terrain reconstruction, the differences of shape and topology among contours in adjacent se... more In 3D terrain reconstruction, the differences of shape and topology among contours in adjacent sections cause a difficulty as the tiling problem of branching terrain. In this paper, we present a brief and pure geometrical algorithm to reconstruct 3D terrain based on contours. The merit of our method is that the tiling rules guarantee arbitrary branching terrain can be divided into correct topology.
The Journal of the Society for Art and Science, 2010
ABSTRACT In CG animation, the method for modeling of CG characters such as humans or animals is i... more ABSTRACT In CG animation, the method for modeling of CG characters such as humans or animals is important. If these shapes are represented by parametric surfaces, such as Bezier, B-spline, or NURBS surfaces, complex procedures are required to make adjacent surfaces connect smoothly. To solve this problem, instead of parametric surfaces, subdivision surfaces are often used to represent shapes. However, how best to fulfill efficient modeling intended by designers is still problematic. Another method is proposed to model complex freeform surface shape, with which the boundary curves of a surface are specified to create a curved mesh and mesh area within the boundary is interpolated with Gregory patches. This kind of modeling method enables to modify a curved mesh directly with intuition so as to achieve a desired shape. In this paper, to take an advantage of the features of both Catmull-Clark subdivision surface and Gregory patch, we propose a local modification method that generates a curved mesh from a polygon mesh with the same topology using a Catmull-Clark subdivision surface, modifies the generated curved mesh directly and applies the modified curved mesh shape to the polygon mesh. One of the characteristics of our method is that modification of some vertices or edges affects only their adjacent surfaces. Also, the surfaces within a specified range can be modified freely with maintaining the continuity between the surfaces and their adjacent surfaces outside the specified area. Applying modification of a curved mesh to a polygon mesh enables local modification or intuitive modification that are rather difficult to perform for a polygon mesh.
ABSTRACT Digital mock-up (DMU) and/or compound document with 3D data are one of the most importan... more ABSTRACT Digital mock-up (DMU) and/or compound document with 3D data are one of the most important methods to represent a product model. Since the data size of 3D models becomes greater year by year, 3D data compression and retrieval algorithm is required to easily exchange such information through the Internet. Because broadband is still not popular in some regions in the world, it is necessary to send huge data in a small size as much as possible. Therefore, in this paper we developed an application system that transfers 3D surface models and then the performance of the 3D surface compression and retrieval algorithm is evaluated.
Subdivision methods are widely used for surface interpolation of a non-four-sided area. Using thi... more Subdivision methods are widely used for surface interpolation of a non-four-sided area. Using this method, smooth surface shape control of multiple surfaces is difficult. Therefore, we used the trim surface for interpolation of a concave area, but shape control of the trim surface was also difficult. In this research, the surface interpolation method of non-four-sided (over 4 sided) area uses a single NBG (NURBS Boundary Gregory) patch. Moreover we apply this method for concave areas and study the ability of interpolation. Interpolation of one-sided and two-sided concave shapes is also considered. As a result, one-sided concave area can be interpolated smoothly for complex cases. Two-sided cases need further study.
... Due to this, we consider additional arrangement for the point data. Gopi's algorithm [10... more ... Due to this, we consider additional arrangement for the point data. Gopi's algorithm [10, 11] uses influence sphere for the sampling criteria. Possible Delaunay neighbors of point p will lie inside this sphere. ... l l k ji, (5) ...
Ninth International Conference on Computer Aided Design and Computer Graphics (CAD-CG'05), 2005
In 3D terrain reconstruction, the differences of shape and topology among contours in adjacent se... more In 3D terrain reconstruction, the differences of shape and topology among contours in adjacent sections cause a difficulty as the tiling problem of branching terrain. In this paper, we present a brief and pure geometrical algorithm to reconstruct 3D terrain based on contours. The merit of our method is that the tiling rules guarantee arbitrary branching terrain can be divided into correct topology.
The Journal of the Society for Art and Science, 2010
ABSTRACT In CG animation, the method for modeling of CG characters such as humans or animals is i... more ABSTRACT In CG animation, the method for modeling of CG characters such as humans or animals is important. If these shapes are represented by parametric surfaces, such as Bezier, B-spline, or NURBS surfaces, complex procedures are required to make adjacent surfaces connect smoothly. To solve this problem, instead of parametric surfaces, subdivision surfaces are often used to represent shapes. However, how best to fulfill efficient modeling intended by designers is still problematic. Another method is proposed to model complex freeform surface shape, with which the boundary curves of a surface are specified to create a curved mesh and mesh area within the boundary is interpolated with Gregory patches. This kind of modeling method enables to modify a curved mesh directly with intuition so as to achieve a desired shape. In this paper, to take an advantage of the features of both Catmull-Clark subdivision surface and Gregory patch, we propose a local modification method that generates a curved mesh from a polygon mesh with the same topology using a Catmull-Clark subdivision surface, modifies the generated curved mesh directly and applies the modified curved mesh shape to the polygon mesh. One of the characteristics of our method is that modification of some vertices or edges affects only their adjacent surfaces. Also, the surfaces within a specified range can be modified freely with maintaining the continuity between the surfaces and their adjacent surfaces outside the specified area. Applying modification of a curved mesh to a polygon mesh enables local modification or intuitive modification that are rather difficult to perform for a polygon mesh.
ABSTRACT Digital mock-up (DMU) and/or compound document with 3D data are one of the most importan... more ABSTRACT Digital mock-up (DMU) and/or compound document with 3D data are one of the most important methods to represent a product model. Since the data size of 3D models becomes greater year by year, 3D data compression and retrieval algorithm is required to easily exchange such information through the Internet. Because broadband is still not popular in some regions in the world, it is necessary to send huge data in a small size as much as possible. Therefore, in this paper we developed an application system that transfers 3D surface models and then the performance of the 3D surface compression and retrieval algorithm is evaluated.
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Papers by Kouichi Konno