SESSION 1: BEGINNING, GEOMETRIC CONSTRUCTION
UNDERSTANDING THE AUTOCAD WINDOW [from ACAD help file]
When you start AutoCAD, the AutoCAD window opens. The window is your design
work space. It contains elements that you use to create your designs and to receive
information about them. The following illustration shows the main parts of the
AutoCAD window.
There are Model Space (Model tab) and Paper Space (Layout tab). Drawing should
be created on the Model Space.
One advantage of AutoCAD over other CAD software is its ability to store drawing
into multiple layers. This is very useful for complex engineering drawing such as
building drawing which consists of architectural plan and system drawings (electrical
wiring, piping, etc).
SOME NECESSARY TOOLS AND COMMANDS
Environment
Toolbar: to view specific toolbars select: View-Toolbars…
Limits: set drawing limits for the “zoom-all” command
Units: to set drawing units (in mm, inches, feet, etc.) and precision.
Drawing Aids
- object snap <F3>. Object snap toolbar is very helpful.
- ortho <F8>
- grid show <F7>
- grid snap <F9>
- to set grid, select Tools-Drafting Settings…
Miscellaneous
Regen: refresh the screen
Layer: each layer can be turn on and off
Zoom
Viewport
Layout
Drawing
Point, pdmode, pdsize
Line
Polyline
Pedit
Circle
Ellipse
Arc
Region
Hatch
Dimension:
Text/mtext
Modifying and Editing
Oops: same as undo but only one step back
Undo: undo the previous actions
Trim
Extend
Copy
Move
Mirror
Erase
Array
Fillet
Chamfer
File operation
Open/Save: the usual format is .dwg
Export
TO DRAW A LINE
-You can always use a mouse to draw a line with the help of grid- and object-snap.
-You can also be specific,
More than one way to draw a line from point A (10,10) to point B (130,60).
Method 1: Specify the two end points
LINE [enter]
10,10 [enter]
130,60 [enter]
Method 2: Use relative method
LINE [enter]
10,10 [enter]
@120,50 [enter]
Method 3: Use relative method and polar coordinates
LINE [enter]
10,10 [enter]
@130<22.6 [enter]
y
B (130,60)
130
50
22.6°
A (10,10)
120
x
TO DRAW A CIRCLE
There are four methods
Method 1 [default]: Specify the center point and the radius
CIRCLE [enter]
100,120 [enter]
20 [enter]
Method 2: Specify any 3 points on the circle
CIRCLE [enter]
3P [enter]
80,120 [enter]
100,140 [enter]
118.5,127.7[enter]
R20
(100,120)
(100,140)
(118.5,127.7)
(80,120)
Method 3: Specify two points at both ends of the diameter.
CIRCLE [enter]
2P [enter]
118.5,127.7 [enter]
81.5,112.3 [enter]
(81.5,112.3)
Method 4: Specify two tangents and the radius (ttr). Very useful, try it yourself.
(118.5,127.7)
ME111 Engineering Graphics (TEP/TEPE)
Geometric Construction
ME111 Engineering Graphics (TEP/TEPE)
Plate no. CAD1
1. Pre-lab Homework (due at the beginning of the lab session)
Read chapter 2 and 9. Complete exercise 9-1.
2. In class assignment (due before noon).
Complete Figure 2A and 2B on the same file and provide complete dimension on a
separate layer. Save the file using your ID and the plate number, for example:
501234567_CAD1.dwg
Figure 2A
Figure 2B