Engineering DrawingFront, Top, SideHoles & CurvesIsometric

Why do we need to learn to draw?• Technical Drawing:• the practice or skill of portraying objects in a precise way

using certain techniques.

• Technical Drawings tell us the following:• Shape• Size of Objects• Types of material that object is constructed of• Finish of Objects• Assembly

Types of Drawings We’ll CoverOrthographic/

Multiview Pictorial

OrthographicGenerating Multi-view Drawings6 Views of an Object

Eliminate the Unnecessary• When we draw objects, we should only include the

views that are needed to fully describe the object• Shape of the object• Shape of features

• When we draw, convention is to use the right side view over the left side view if they both show the object equally well

• Likewise, the top view is preferred to the bottom view if they both show the object equally well

• Showing only the necessary views saves time, makes the drawing less cluttered, and makes the drawing easier to interpret

Multi-view Setup• Primary Views: top, front, right side• Secondary Views: Left side, rear, bottom• There is always one dimension in common

between adjacent views• 4 angles of projection. Third angle projection is

the multi-view setup used by the U.S.A. First angle projection is used in Europe.

Creating a Three-view sketch:•Step 1: Block in the front, top, and right side views. Sketch the front view first using construction lines to project dimensions•Step 2: Lightly block the major features in views•Step 3: Use construction lines to project the location and size of features between views•Step 4: Finish adding the final

lines

Let Us PracticeStep-by-step

LINES!

Hidden Lines• Lines with short, evenly spaced, dashes

• Indicate edges that you cannot see in a view

Center Lines• Thin lines of alternating, long and short, dashes

• Show centers of holes and axes of symmetry

Dimension Lines

Extension Lines

Order of Precedence• Visible Lines Hidden Lines Center Lines

Practice!

Creating an Isometric Drawing