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Volume 54 (2020)
- Issue 2 Pages 3-
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Volume 54, Issue 2
Displaying 1-7 of 7 articles from this issue
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Reserch Paper
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─ study using differential geometry ─Osamu ARIMA2020 Volume 54 Issue 2 Pages 3-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSThis report describes the method for generating a developable surface between two space curves and obtaining a development of it.
On ruled surfaces, the existence of a tangent plane is equivalent to its being a developable surface. Therefore, the generators are determined so as to be a developable surface between two space curves, and a development is created using a generalized unfolding formula for the developable surface generated in this way.
In this method, it is possible to obtain a development uniformly without considering the types of developable surfaces. It is theoretically impossible to draw a development of a surface other than a developable surface, because the surface generated between two space curves is guaranteed to be a developable surface.
If two space curves cannot generate a developable surface, a development cannot be obtained. However, the existence of a tangent plane can be easily determined because it can be imaged without complicated calculations.View full abstractDownload PDF (6200K) -
Kazushi MARUYA, Tomoko OHTANI2020 Volume 54 Issue 2 Pages 13-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSWhen the shadows of a group of linear columns projected on a stepped three-dimensional (3D) plane are diagonally viewed, the retinal image shows a geometric pattern that is similar to the Café wall illusion, which is a popular geometric illusion. In this study, we investigated the relationship between the geometric structure of the scene, such as the 3D shape, viewing angle, and direction of the light source, and the strength of the Café wall illusion that was perceived from the retinal image of those 3 D situations. Consequently, the difference in the depth at which the shadows fall should be approximately 1%–2% of the observation distance to result in a strong Café wall illusion. These results show that the information of the shadow that falls on the object is an effective clue for estimating the shape of the object surface with relatively small depth differences in the case of large viewing distances.View full abstractDownload PDF (2463K)
Notes
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Shoko KAWATA, Kazuki TAKENOUCHI2020 Volume 54 Issue 2 Pages 19-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESS -
Koichi FUKUDA, Ayaka OHTSUKI, Kazuki TAKENOUCHI2020 Volume 54 Issue 2 Pages 25-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSThe multiview projections drawn in Monge's Descriptive Geometry had been represented in Gutenberg's printing technique books before Monge as well. These fields include art, architecture, civil engineering, shipbuilding and fortification. Some of these figures are comparable to the problems and solutions in Descriptive Geometry.
Overseas, studies on Monge's works have been actively conducted until recently and have been reported in academic societies and books.
This paper provides an opportunity to re-recognize the role that Monge played by introducing examples of geometrical figure and technical drawing together with previous studies, and following the process that Monge invented Descriptive Geometry.View full abstractDownload PDF (3777K) -
Sande GAO2020 Volume 54 Issue 2 Pages 33-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSIndustrial products with free-form surfaces become more popular recently as people pursue not only the functions of a product, but also its design quality and elaboration which are essential for an enjoyable experience of using the product. An effective method to design this type of product is reverse engineering assisted with the tools used in computer aided design/manufacturing/testing (CAD/CAM/CAT). In our research, a 3 D scanner was used to measure a model car body in three subjects. The measured data in the stl (stereolithography) format represented as an aggregate of small triangles cannot be used for computer aided numerical control (CNC) fine machining. To solve this problem, they were converted into a CAD model by using 3 D-CAD software CATIA V5. This paper presents the issues such as the efficiency in modeling the surface and the smoothness and accuracy of CAD model created through reverse engineering.View full abstractDownload PDF (2017K) -
Shigeo HIRANO, Susumu KISE, Sozo SEKIGUCHI, Kazuya OKUSAKA, Tsutomu AR ...2020 Volume 54 Issue 2 Pages 39-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSJapanese Industrial Standards (JIS) B 0001 (Technical drawings for mechanical engineering) were revised on 20 May 2019. Although many revisions have been made on conventional standards, there still remain errors in terminology, misuse of drawing rules, and difficulty in understanding the standards without careful reading. Students and engineers who are novice at technical drawings start their study without any previous knowledge and assume that JIS contain no errors. This study is conducted to clarify the basic items required for studying technical drawings and a design and drawing education method is proposed as part of the revised standards.View full abstractDownload PDF (1999K)
Zugaku Note
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Kokichi SUGIHARA2020 Volume 54 Issue 2 Pages 47-
Published: 2020
Released on J-STAGE: September 01, 2021
JOURNAL FREE ACCESSThis paper presents a design principle for triply ambiguous objects. An orthographically projected picture of a rectangular object has exactly three groups of parallel edges. When this picture is placed on a horizontal plane and is seen in a slanted direction such that one group of parallel lines becomes vertical on the retina, we perceive a vertically compressed 3D object. This process gives three different interpretations of the picture, and thus creates triple ambiguity. We can strengthen the illusion by inserting real 3D objects that show the direction of gravity. An example of this object won the first prize at the Best Illusion of the Year Contest 2018.View full abstractDownload PDF (1346K)
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