chapter 5 technical sketching & shape description instructor: m.yaqub

Chapter 5Technical Sketching & Shape

description

Instructor: M.Yaqub

Technical Sketching• Sketching Material: only paper, pencil and

eraser is required for free hand sketching.

• Types of sketches: Can be Isometric, oblique, multi-view or perspective.

• Scale: Generally drawn not to scale but in correct proportions.

The most important rule in free hand sketching is

keep the sketch in proportion

Perspective view: one vanishing point

Views of Objects

• A pictorial view can not describe the object fully.

• In industry, a complete information is required about shape and size.

• To provide all information, a number of views are used called multi-view projection.

• The three principal dimensions are depth, height and width. Any two can be shown in one view.

Front view: From where the object is mostly used.

Necessary Views

Meanings of Lines: Visible line could be 1) Intersection of two surfaces2) Edge view of a surface3) Contour view of a curved surface

Precedence of Lines

• A visible line always takes precedence over a hidden or center line (A and B in Fig. 5-49).

• A hidden line takes precedence over a center line (C in Fig. 5-49).

• Ends of the center line are shown in A and C