Engineering H191 - Drafting / CAD
Review of Descriptive Geometry
Lecture 10
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 1
Engineering H191 - Drafting / CAD
Topics For Today
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Quiz – CAEG – AutoCAD
Drawing Number 18 is due
Lab report due on Wednesday at the beginning
of the lab period
Lab Report – Follow the example, calc. % at each
speed, graph in %, use two mph groupings (24
and 25 – avg 24.5) or three mph groupings (24
thru 26 -- avg 25)
Descriptive Geometry
– Read BTG Chapter 11
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 2
Engineering H191 - Drafting / CAD
Review from Monday
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Lines and planes extend to infinity while we work with a
small portion which we define.
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Lines and planes can be extended.
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Dihedral angle – The angle between two planes – smaller
of the two. It can be found by finding the line of
intersection and looking at the line of intersection as a
point.
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Angle between a line and plane – This requires a view in
which the plane is an edge and the line is true length.
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 3
Engineering H191 - Drafting / CAD
Review from Monday
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Downloaded a blank3d template – 4 viewports,
3D construction, world coordinates, cursor
tracking – world
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Layout mode – Transferring the model to paper
– tab at the bottom of screen
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The layout and the model or construction mode
are all part of one file.
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 4
Engineering H191 - Drafting / CAD
Review from Monday
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VIEW – Using UCS menu
– 3 UCS + plan (enter) (enter) – gives true size
of plane
– Z UCS + plan (enter) (enter) – gives end view
of line which could provide edge view of a
plane or a dihedral angle
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 5
Engineering H191 - Drafting / CAD
Construction Hint
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When you have created a line and then look
down the line so the line appears as a point, it
disappears in AutoCAD. When you know this is
going to happen, place a point (+) at each end of
the line.
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Save often but don’t overwrite the blank3D file.
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 6
Engineering H191 - Drafting / CAD
Key to Descriptive Geometry
Top
Know the location of the origin
(0,0,0)
Front
Right Side
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 7
Engineering H191 - Drafting / CAD
Angle between a line and plane
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Required – a view where the line is true length
and the plane is an edge
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In pencil construction, three auxiliary views are
required 1) edge view of plane 2) true size of
plane 3) edge view of plane and true length of line
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Using the UCS menu and the PLAN command
shortens the process
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 8
Engineering H191 - Drafting / CAD
Today’s Assignment
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Dwg 19 – SGAC-4-1
– Angle between a line and a plane in space
– Due at end of class today
– Read Handout – steps for solving problems
in AutoCAD are provided
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Dwg 20 – SGAC-4-2
– Dihedral Angles
– Due at beginning of next lecture
– Read Handout – steps for solving problems
in AutoCAD are provide
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 9