Geometry for Modeling and Design
- Objectives
- Overview
- Coordinates for 3D CAD Modeling
- Geometric Entities
- 4.1 Manually Bisecting a Line or Circular Arc
- 4.2 Drawing Tangents to Two Circles
- 4.3 Drawing an Arc Tangent to a Line or Arc and through a Point
- 4.4 Bisecting an Angle
- 4.5 Drawing a Line through a Point and Parallel to a Line
- 4.6 Drawing a Triangle with Sides Given
- 4.7 Drawing a Right Triangle with Hypotenuse and One Side Given
- 4.8 Laying Out an Angle
- 4.9 Drawing an Equilateral Triangle
- 4.10 Polygons
- 4.11 Drawing a Regular Pentagon
- 4.12 Drawing a Hexagon
- 4.13 Ellipses
- 4.14 Spline Curves
- 4.15 Geometric Relationships
- 4.16 Solid Primitives
- 4.17 Recognizing Symmetry
- 4.18 Extruded Forms
- 4.19 Revolved Forms
- 4.20 Irregular Surfaces
- 4.21 User Coordinate Systems
- 4.22 Transformations
- Key Words
- Chapter Summary
- Skills Summary
- Worksheets
- Review Questions
- Chapter Exercises
In this sample chapter from Modern Graphics Communication, it prepares the reader to master various AutoCAD skills. The section promises to teach essential techniques, such as identifying basic geometric elements, selecting 2D profiles, recognizing mirrored shapes and their symmetry, and understanding shapes created by extrusion or revolution. Additionally, it covers defining and applying Boolean operations, working with Cartesian and user coordinates, and identifying common CAD transformations. These foundational skills set the stage for more complex shape creation and CAD system navigation, with more detailed discussions to follow in subsequent sections of the book.
This chapter is from the book
This chapter is from the book
This chapter is from the book
Objectives
After studying the material in this chapter, you should be able to:
Identify and specify basic geometric elements and primitive shapes.
Select a 2D profile that best describes the shape of an object.
Identify mirrored shapes and sketch their lines of symmetry.
Identify shapes that can be formed by extrusion and sketch their cross sections.
Identify shapes that can be formed by revolution techniques and sketch their profiles.
Define Boolean operations.
Specify the Boolean operations to combine primitive shapes into a complex shape.
Work with Cartesian coordinates and user coordinate systems in a CAD system.
Identify the transformations common to CAD systems.
Additional geometric constructions are located in Appendix 52.
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Many different geometric shapes were used to model this jetboard. The wireframe view of the top cover reveals several regular geometric shapes used to model the interior components. The graceful lines of the outer hull are defined by the irregular curves used to model it. (Courtesy of Leo Greene, www.e-Cognition.net.)