Ch.5 Multiview Drawings Objective: Learn the rules for reducing a 3D object onto a 2D multiview drawing and learn some hints for visualizing a 3D object from a 2D multiview drawing. Projection theory and multiview projection planes (5.1 through 5.3) 6 principal views (5.4) View selection rules (5.5) Fundamental views of edges and planes (5.6) Multiview representations (5.7) Multivew drawings visualization and summary (5.8 & 5.10) ANSI standards for multiview drawings (5.9)

Multiview Projection (5.1 through 5.3) See Fig. 5.1 to locate the multiview projections in the taxonomy of projects: Projection  Parallel projections  Orthographic projections  Multiview projections. Object Projection plane Line of sight

Multiview Projection Multiview projection is an orthographic projection for which the object is behind the plane of projection, and the object is oriented such that only two of its dimensions are shown.

6 principal views (5.4) Open up the glass box, producing the 6 principal views.

US (ANSI 3rd-angle projection) vs. ISO (1st-angle projection)

Steps to create a 3-view multiview drawing

View selection (5.5) Determine the best position of the object. Try to make the surfaces of major features either perpendicular or parallel to the projection planes. Define the front view. The front view should show the object in its natural or assembled state. Determine the minimum number of views is needed to completely describe the object so it can be produced. Once the front view is selected, determine which other views will have the fewest number of hidden lines.

View selection (cont.) Bad orientation Good orientation

Fundamental views of planes (5.6) Normal plane Oblique plane Inclinedplane

Fundamental views of edges Oblique line Normal line (true-length line) Inclined line

Normal, inclined, or oblique?

Multiview representations (5.7) Many examples of multiview representations are given in this chapter. The best method to learn the art of multiview representation of 3D objects is to draw by yourself, with tools or freehand, the objects shown in Figures 5.47 through 5.68. We do not have time to cover all that are presented in the chapter. I present here only those that require a bit of explanations.

Multiview representations (5.7)

Multiview drawings visualization (5.8 & 5.10) Practice makes perfect. Without it, you will never learn this art of visualizing 3D objects from 2D multiview drawings. Projection studies Physical model construction Adjacent labeling Missing lines Vertex labeling Analysis of solids Analysis of surfaces

Multiview drawings visualization (5.8 & 5.10), cont.

ANSI Standards for multiview drawings (5.9) Partial view

ANSI Standards for multiview drawings (5.9) Revolution Too “busy”

ANSI Standards for multiview drawings (5.9) Revolution Removed view Make the drawings easy to understand!