1. Orthographic Projection Basics
Chapter 10 of Text

2. Objectives Discuss the principles of orthogonal projection
Show how and why orthogonal projection is used to create multiple views of an object for formal engineering drawings
Create a multiview drawing from a 3-D object
Note: The terms orthogonal and orthographic are used to refer to the same drawing type.

3. Why Orthographic Drawings?
The best way to communicate what an object looks like is to show someone an image.
Isometric sketches distort the features of an object and may lead to misinterpretation.
Objects must be represented in a way that prevents misinterpretation.
Multiview drawings show how an object looks from multiple angles.
Multiviews help to prevent any mis-communications that may happen when looking at only isometric pictorials.

4. Orthographic Projections
Orthographic projections are another way of representing a 3D object in 2D space.
In an orthographic projection, the object is projected perpendicularly onto a viewing plane.
By using a multiview drawing, we can eliminate misinterpretations that isometric views alone allow.

5. Orthographic Projections
When drawing an orthographic multiview, it sometimes helps to visualize the object inside of a glass box.
Imagine that the object is projected on to each surface of the glass box.
The box is then unfolded to form the multiview drawing.

6. How Many Views Do We Need?
Just projecting one view of a surface isn’t enough to completely describe the object
This single view can be interpreted in at least 6 different ways!
To completely describe the object multiple views are shown.
Generally, the front, top, and right side are sufficient to fully represent an object.

7. Orthographic Projection
Use your snap cubes to build the following object.
Look at if from the front, right, and top sides.
Note: These are the 3 views associated with the object you just built.
Top
Front
Right
Top 2 1
CLICK
Front
Right

8. Orthographic Projections
Typically, the front, top, and right side views are sufficient to fully describe an object.
Right
Top
Front
Top
Need a slide after this one that talks about view alignments
Front
Right

9. View Alignments
Width
In orthographic projections, the views are aligned such that each point on the object is lined up with itself all three views.
Each view shows two dimensions
Top: width and depth
Front: height and width
Right side: height and depth
Height
Width B A B
Depth
Depth A B B
Height
Height A A
Width
Depth
CLICK

10. Orthographic Projections
Use this time and your snap cubes to practice building objects and sketching orthographic projections.
In class assignment