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Volume 19 (1985)
- Issue 2 Pages 3-
- Issue 1 Pages 1-
Volume 19, Issue 2
Displaying 1-7 of 7 articles from this issue
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-3-D Display by Using Optical Cut Images-Sadahiko NAGAE, Masaru SHIBATA, Takuzi KURASHITA, Takao MIYAMOTO, Sets ...1985 Volume 19 Issue 2 Pages 3-8
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSAnalogue graphic data obtained from CT images, or similar sectional images are converted into digital ones by using a X-Y digitizer, and the original 3-D object is reconstructed by processing with a personal computer. After the oblique projection method is confirmed in synthesis of optical sectional cut images for concavo-convex glass model in an experiment, the color graphic display for human bone is attempted by processing the CT scanning images.View full abstractDownload PDF (4454K) -
Hirotaka Ebisui1985 Volume 19 Issue 2 Pages 9-14
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSThe Cartesian ovals are simply defined with bipolar coordinates. However it is difficult to draw them by handwriting. In this paper, therefore, we have constructed a computational drawing system by means of XY plotter that works with PC 8001mkII. And then, the ovals will show some particular properties. First, the ovals change gradually with left and right eccentricities. Second, the set of the intersections of three circles forms the oval. Third, when the eccentricities change continuously without changing the director circle and the foci, the ovals fill between the ellipse and the director circle. Forth, there can be shown two kinds of evolutes of the ovals. The one is drawn as an evelope of the straight lines, and the other with paramatric equations. In this way, these properties of the oval can be shown for the first time by using computational drawing system.View full abstractDownload PDF (1129K) -
Shinobu Nagashima1985 Volume 19 Issue 2 Pages 15-19
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSIn computer graphics and geometric modeling, polyhedron's inside test, a determination whether a given point lies inside or outside a polyhedron, plays an important role. However, this cannot be realized easily. Since former methods have some difficulties, a yew method of design is introduced in this papaer.
When all polygons of polyhedron's faces are projected ont.o a sphere whose center lies on the given point with radius of 1, the sum of area becomes 4π i f the point lies inside the polyhedron. Otherwise, this becomes 0. Though it is difficult to calculate an area of the polygon on the sphere, it can be calculated by dividing the polygon into triangles.
This new algorithm of inside test was programmed and applied to two kinds of object, one, a cube and the other an octagonal prism. As a result, the errors of area's calculation for 4π was under 0.03%. These figures confirms that the test can be applied to rather complex objects.View full abstractDownload PDF (415K) -
[in Japanese]1985 Volume 19 Issue 2 Pages 21-24
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSDownload PDF (276K) -
[in Japanese]1985 Volume 19 Issue 2 Pages 25-29
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSDownload PDF (383K) -
[in Japanese], [in Japanese]1985 Volume 19 Issue 2 Pages 31-38
Published: 1985
Released on J-STAGE: August 25, 2010
JOURNAL FREE ACCESSDownload PDF (621K) -
1985 Volume 19 Issue 2 Pages 39-49
Published: 1985
Released on J-STAGE: December 09, 2010
JOURNAL FREE ACCESSDownload PDF (1048K)
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