desn 106 -36n descriptive geometry - faculty...
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![Page 1: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/1.jpg)
Descriptive Geometry CH17 : DEVELOPMENTS
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A development is a flat representation or pattern that when folded together creates a 3D object.
Developments
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A developable surface may be unfolded or unrolled to lie flat. Surfaces composed of single-curved surfaces, of planes, or of combinations of
these types are developable.
Developable Surfaces
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The development of a surface is that surface laid out on a plane. Practical applications of
developments occur in sheet metal work, stone cutting, pattern making, packaging, and package
design. (Courtesy of Kessler Brewing Co.)
Developments
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Parallel Line Developments - Prism To develop the surface of a prism, three conditions must be known: 1. The true lengths of the lateral edges. 2. The relative positions of the parallel edges with respect to a right
section (a plane figure formed by the intersection of a cutting plane perpendicular to the axis of a form).
3. The perimeter of the right section of the prism or perpendicular distances between the lateral edges.
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Parallel Line Developments - Prism 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 7: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/7.jpg)
Parallel Line Developments - Prism 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 8: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/8.jpg)
Parallel Line Developments - Prism 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 9: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/9.jpg)
Stretch-Out Line In the given example, the lower base plane is perpendicular to the lateral edges, and hence its perimeter unrolls into a straight line perpendicular to the parallel lateral edges in the development. This line is called the stretch-out line.
Note that the stretch-out line is started on a line of symmetry and that for economy the seam is started at the shortest lateral edge. If the right section has a line of symmetry, only a half development needs to be drawn.
![Page 10: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/10.jpg)
Parallel Line Developments - Prism 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 11: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/11.jpg)
Problem 2 • Draw the given views and complete the development.
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Parallel Line Developments - Cylinder To develop the surface of a cylinder, three conditions must be known: 1. The true lengths of the lateral edges. 2. The relative positions of the parallel edges with respect to a right
section (a plane figure formed by the intersection of a cutting plane perpendicular to the axis of a form).
3. The perimeter of the right section of the prism or perpendicular distances between the lateral edges.
![Page 13: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/13.jpg)
Parallel Line Developments - Cylinder 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 14: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/14.jpg)
Parallel Line Developments - Cylinder 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 15: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/15.jpg)
Parallel Line Developments - Cylinder 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 16: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/16.jpg)
Parallel Line Developments - Cylinder 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals
![Page 17: DESN 106 -36N Descriptive Geometry - Faculty Webfaculty.ivytech.edu/~bl-desn/dsn106/images/WK11-CH... · Descriptive Geometry CH17 : DEVELOPMENTS . A development is a flat representation](https://reader035.vdocuments.net/reader035/viewer/2022062907/5a8e53d67f8b9af27f8cd48a/html5/thumbnails/17.jpg)
Parallel Line Developments - Cylinder 1. Find the TL of the
laterals (edges) 2. Construct a right
section (in this eg: find the TS of the base)
3. Construct a stretch-out line starting with the shortest lateral, using the perimeter distances from the right section.
4. Draw the laterals using their TL.
5. Connect the endpoints of the laterals – For inclined surface use a spline (fit option)
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Problem 1 • Draw the given views and complete the development.