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 an example of an isometric 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, isometric 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 Drawing The lines of the edges of a cube in isometric 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 DEGREE ANGLES Laying out the angles…

10 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Non-Isometric Lines Lines of an isometric drawing that are not parallel to the isometric axes are called non-isometric lines These lines are those that do not follow the pattern

11 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

12 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

13 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 A 2 X 2 X 2 CUBE Start with construction lines of your critical angles FRONT TOP RIGHT SIDE

14 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 A 2 X 2 X 2 CUBE Mark out along those lines the lengths needed. Use actual lengths! Project from the right side information to the top and the front.

15 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 A 2 X 2 X 2 CUBE Connect all needed points, and then darken to finalize.

16 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 Creating an overall outline of the object gives the draftsman points of reference and can be a time saver vs. trying to just draw just the minimum information.

17 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

18 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Using “Point Reference” Getting the right information… We need to use point reference vs. angular reference because we cannot transfer angles directly into drawing.

19 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Using Reference Points…. Draw an overall outline of the drawing. Mark any reference points for the non-isometric surface Draw in the surface by connecting the reference points Finalize by darkening object lines. FR TOP RS

20 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

21 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

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

23 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Irregular Objects Start with “what you know” (the square ends), then draw the sections in using them as “Points of Reference” to construct the rest of the drawing. You must draw each section in Orthographic and then transfer it to the Isometric Drawing.

24 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

25 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

26 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 *Notice how each circle appears different in each of the views.

27 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 Start with creating critical points (where to put the needle and where to start the arcs)

28 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 Place needle and let the end lines dictate the radius.

29 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 * Notice how each circle appears different in each of the views.

30 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Drawing a Specific Size Circle in Isometric If you need a circle that is 1” in diameter then you need to construct a 1” square in isometric. (e.g. Right side) Then follow the pattern used in the box to construct a proper ellipse. Remember to use the pattern that will complete an ellipse that sits at the proper angle according to the view.

31 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 FROM THE ORIGINAL ELLIPSE, PROJECT IN THE DIRECTION OF THE CYLINDER THE POINTS WHERE THE NEEDLE IS TO BE PLACED. THE PROJECTION LINES SHOULD BE THE LENGTH OF THE CYLINDER.

32 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

33 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

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

35 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

36 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

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

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