Technical Drawing
Visual Communication of
Technical Information
Technical Drawing
Visual Communication of Technical Information
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Unit Overview – several classes
Precise Drawings Give More Information
Types of Technical Drawing
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Isometric Projections
Parallel, Perspective, and Oblique
Orthographic Projections
Multi-view Sketches
Practice
Tech Drawing -- Overview
Good drawings convey detailed
information about solutions to technical
problems. In this unit you may learn:
 Technical Drawing (focus of two types)
 Puzzle cube design and fabrication
 Orthographic and Isometric Layouts
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Manufacturing diagrams
How can we present an object
and learn the most about it?
This view shows a square object with a number and some other detail
Isometric Projection
This view shows two sides and more information.
Note: All vertical lines are parallel
Isometric Projection
This view shows three sides and even more
information. All vertical lines are parallel; all other
lines are 30 to 60 degrees above the horizon.
Isometric Projection
A see-through version lets us infer information
about the hidden sides
Oblique Projection
The front is drawn on the X and Y axes. The side and top
are drawn at an oblique (not square) angle in the Z
direction.
A lot of information is shown regarding the front; less about
the top and side.
Parallel Projection
Parallel lines remain parallel regardless of
how they really appear. Are these beams
parallel?
Perspective Projection
Parallel lines meet in the distance as they
really appear
Perspective and Parallel
The cube is scaled to be 12 ft.
How can we make a standard
drawing of this object?
To begin:
All vertical lines are perpendicular
to the horizon
Horizon
Next:
All other lines rise at 30 degrees
from the horizon
Horizon
Continue:
All lines that complete the diagram
are parallel to one of the three
main lines
Horizon
Complete:
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The final isometric drawing presents
three sides and infers information about
the other sides
Horizon
Practice
Height
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Take a few
minutes to
copy EACH of
these
isometric
figures in your
notebook or
on plain paper
Width
Depth
Start with each of
the three
isometric axes
1.
2.
Add vertical lines
from the corners.
They should be
parallel to the center
line
Practice
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Take a few
minutes to
copy EACH of
these
isometric
figures on a
practice sheet
Add lines for width
parallel to the
width axis
3.
Finish the cube
with lines for
depth parallel
to the depth
axis
4.
Erase where you need to
Practice
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Draw an
isometric
sketch of the
boxes in the
diagram
This is Isometric Paper
To make drawing easier
Use isometric paper
Graph paper with lines
That follow isometric
60-degree axes
Use this to practice
Drawing isometric
figures
Horizon
More Practice
There are seven
3-D figures
made of cubes
on your work
sheet.
Construct each
using plastic
cubes.
`
More Practice
Then draw
each on
isometric
paper.
Isometric Projection
A standard method of 3dimentional (3D) drawing that
shows the most detail about
three adjacent sides of an
object.