CMCE 1110 Construction DrawingsProfessor Anderson

Lesson 1:

Orthographic Projection

Orthos – Graphē (Greek)

“Straight - Drawing”

ORTHOGRAPHIC PROJECTIONis a means of representing a three-dimensional object in two dimensions. It is a form of parallel projection, where all the projection lines are orthogonal to the projection plane, resulting in every plane of the scene appearing in affine transformation on the viewing surface.

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PROJECTION METHOD: GLASS BOX

TYPICAL VIEWS:- Top/Bottom (Plan)- Front and Sides(Elevations)

Relationship Between Views

Orthographic views are based upon projection

Basic Procedures for Orthographic Projections:

1. Study the basic shape of the object.2. Draw the front view to scale3. Project the top view above: draft

vertical construction lines at all object features

4. Project the side view, aligned with the front viewa) Extend horizontal construction

lines from top viewb) Make the “turn” using a 45°

line to extend these lines down to project the side view

c) Extend horizontal construction lines from front view

d) Complete the side view.5. Complete views – proper line

weights and types 6. Fully dimension and label each

view

Hidden Lines:Imagine that you can look through a solid object to see “hidden” edges. The edges are indicated with “hidden” dashed lines.

TRY IT!

TRY IT!

½”

2”

1”

1

½”

1 ½”

1” Drill

½” Radius3/4” Drill 3/8”Radius

Hidden Line for

¾” radius

WHEEL BLOCK AXLE BRACKET

METAL BENDER

PIPE JIG