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