Axonometric Projection Chapter 14

2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Objectives Describe the differences between multiview projection, axonometric projection, oblique projection, and perspective Sketch examples of an isometric cube, a dimetric cube, and a trimetric cube

3 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Objectives (cont.) List the advantages of multiview projection, axonometric projection, oblique projection, and perspective Create an isometric drawing given a multiview drawing Use the isometric axes to locate drawing points

4 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Objectives (cont.) Draw inclined and oblique surfaces in isometric Draw angles, ellipses, and irregular curves in isometric

5 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Projection Methods

6 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Types of Axonometric Projection Isometric – has equal foreshortening along each of the three axis directions Dimetric – has equal foreshortening along two axis directions and a different amount on the third axis Trimetric – has different foreshortening along all three axis directions

7 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Types of Axonometric Projection

8 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Projection The projections of the edges of a cube in isometric projection make angles of 120 degrees with each other

9 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Projection Lines of an isometric drawing that are not parallel to the isometric axes are called nonisometric lines These lines are not equally foreshortened

10 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Projection Isometric scales can be used to draw correct isometric projections All distances are approximately 80% of true size

11 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Drawings Isometric drawings, unlike isometric projections, are drawn using the full length measurements of the actual drawing and lacks foreshortening The isometric drawing is about 25% larger than the isometric projection

12 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Making an Isometric Drawing

13 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Drawings of Inclined Surfaces

14 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Hidden Lines and Centerlines Hidden lines are omitted unless they are needed to make the drawing clear Center lines are shown if they are needed to indicate symmetry or if they are needed for dimensioning

15 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Angles in Isometric Angles project true size only when the plane containing the angle is parallel to the plane of projection An angle may project to appear larger or smaller than the true angle depending on its position

16 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Irregular Objects

17 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Irregular Objects

18 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Curves in Isometric

19 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Ellipses in Isometric If a circle lies in a plane that is not parallel to the plane of projection, the circle projects as an ellipse Ellipses can be constructed using offset measurements

20 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Ellipses in Isometric Approximate ellipses can be constructed from arcs

21 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Drawing Isometric Cylinders

22 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Screw Threads in Isometric Parallel partial ellipses equally spaced at the symbolic thread pitch can be used to represent screw threads

23 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Arcs in Isometric

24 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Intersections

25 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Spheres in Isometric

26 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Sectioning Isometric sectioning is useful in drawing open or irregularly shaped objects

27 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Isometric Dimensioning Isometric dimensions are similar to dimensions on multiview drawings but should match the pictorial style

28 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Exploded Assemblies

29 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Piping Diagrams

30 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Dimetric Projection A dimetric projection is an axonometric projection of an object where two of its axes make equal angles with the plane of projection and the third axis makes either a smaller or a greater angle

31 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Dimetric Projection

32 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Trimetric Projection Trimetric projection is an axonometric projection where no two axes make equal angles with the plane of projection Each of the axes have different ratios of foreshortening

33 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Ellipses in Trimetric

34 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Axonometric Projections Using Intersections Before computer automated drafting, a method was devised to create axonometric projections using projections from orthographic views

35 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Axonometric Projections Using Intersections