AutoCAD Tutorial and Assignment

AutoCAD Tutorial and Assignment Instructions
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AUTOCAD TUTORIAL AND ASSIGNMENT INSTRUCTIONS
Department of Chemical Engineering, Loughborough University
1. PRELIMINARY INFORMATION
2. AutoCAD SOFTWARE TUTORIAL
2.1 AutoCAD basics
2.1.1 Starting
2.1.2 Mouse operations
2.1.3 Command selection
2.1.4 Starting your drawing
2.1.5 Escape routes
2.2 Example tabs, menus and commands – Self-learn for Assignment 1
2.2.1 Draw menu (Circle, Rectangle, Ellipse, Arc, Line, Polyline)
2.2.2 Annotation menu (Text)
2.2.3 Modify menu (Erase, Copy, Rotate, Mirror, Trim, Extend)
2.2.4 Properties menu (Linetype, Lineweight)
2.2.5 Navigate 2D/View menu (Zoom, Pan, Window)
2.2.6 Drawing aids (Snap, Grid, Ortho, Object Snap)
2.2.7 Saving and printing your drawing
2.2.8 Finishing-off and exiting AutoCAD
2.3 More commands (Hatch, Fillet, Dimension) – Self-learn for Assignment 2
3. INSTRUCTIONS FOR COURSEWORK ASSIGNMENTS
1. PRELIMINARY INFORMATION
The purpose of technical drawing is to communicate and store information. The drawings
of most significance to chemical engineering are those representing processes or the
items of equipment used in processing. The aim is to give guidance in flowsheeting and
practice using AutoCAD. Assessment is based on two practical exercises (together worth
25% of the module).
2. AutoCAD SOFTWARE TUTORIAL
2.1 AutoCAD basics
AutoCAD is a drawing package with almost unlimited 2-D, and significant 3-D, ability.
This document contains enough information to introduce you to AutoCAD’s conventions
and commands. No attempt is made to cover all of AutoCAD’s capabilities. You can find
out more by using the software for yourself, viewing the integral AutoCAD help facilities
and/or referring to the text books in Section 620.004 of the Pilkington Library.
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The following explains how to start AutoCAD, the steps required to take you to the starting
point for your new drawing and some basics about the screen display.
2.1.1 Starting
Switch on the computer, log on and wait for the desktop to appear. To start AutoCAD use
the mouse to select the sequence Start – All Programs – Autodesk – AutoCAD. A
screen display similar to Figure 1 should appear.
Figure 1: Example of the screen display in AutoCAD.
• At the bottom of the screen is the Status Line which displays the x,y,z co-ordinates of
the cursor and some drawing aid buttons such as Snap and Object Snap (OSNAP).
• Toward the bottom of the screen are lines of text. These Monitor lines provide a
running commentary on your session and allow drawing command values to be set.
• The main part of the screen is the Drawing Space that contains your drawing. The
items that you draw will appear as white on the black background but print vice versa.
• Near the top of the screen is the Ribbon which contains the Tabs, Toolbar buttons
(shortcuts) and drop-down menus with the AutoCAD commands. Hovering the mouse
over many of these buttons reveals ‘tip text’ that briefly describes their function.
• Additional menus that appear over the Drawing Space can be closed as desired.
Move your mouse until you have a cross-hair (or cross) cursor on the drawing. Notice that
the co-ordinates of this cursor are shown on the Status Line.
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Use the mouse to point toward the bottom of the screen (Status Line). Notice the drawing
aid buttons that you can switch on by clicking with the left mouse button (e.g. Grid). You
can alter their settings using the menus accessed with the right mouse button.
You may exit AutoCAD by following the instructions in Section 2.2.8.
2.1.2 Mouse operations
To make best use of the mouse you need to know what the two buttons do. The left
mouse button is the select button and a single click:
• Selects an item from a menu – same as typing a menu item name in the Monitor lines.
• Selects Objects on the screen.
• Selects a point on the drawing – same as typing the x,y co-ordinates.
The right mouse button reveals the <Return> or <Enter> options/button. A click:
• Accepts a default value, <often displayed in angle brackets> on a Monitor line.
• Repeats the last command.
• Exits a Select Objects Loop – see Section 2.2.3.
2.1.3 Command selection
You can choose an AutoCAD command by either:
• Typing the command name or its abbreviation in the Monitor lines, then <Return>.
• Selecting the command with the Toolbar buttons (if available).
• Selecting the command via the menus.
2.1.4 Starting your drawing
To enhance progress you should find it helpful to ensure that ‘Snap’, ‘Grid’ and ‘Object
Snap’ are set on. For more information see Section 2.2.6 about Drawing Aids.
It is often helpful to draw a rectangle the size of an A4 sheet (297×210, 300×210 is close
enough), i.e. a common size for printing. Refer to Section 2.2.1 for how to do this.
2.1.5 Escape routes
During your coursework assignments you may encounter one or more of the following:
• You are stuck in a command, press <Esc> or start a new command sequence.
• You are in the Drawing Space but your drawing is not: Try View – Pan or Zoom (or
scroll wheel on the mouse).
• Your computer is not responding: Simultaneously press <Ctrl> <Alt> and <Del> and
then take appropriate action. This is a last resort, you may lose recent drawing editing.
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2.2. Example menus and commands
A large range of AutoCAD commands are available to you. The following represents a
brief description of a few commands to get you started.
2.2.1 Draw menu (on Home tab)
Here you can select an item to draw and place it on your drawing.
Circle, Rectangle, Ellipse and Arc
➢ Use the mouse to select (left button) Circle. There are many ways to define a circle in
AutoCAD and these different ways are displayed in the Monitor lines. The default is
the ‘Centre, Radius’ option.
➢ Move the cursor onto the screen and select a centre point for your circle.
➢ Move away with your cursor to drag a ghost circle onto the drawing.
➢ Select a point at the desired radius to complete the Circle command. Alternatively,
specify a radius in the Monitor lines or box adjacent to the cursor.
A rectangle can be drawn by a similar technique using Rectangle, as can an Ellipse
which requires two radii to be chosen. An Arc can be drawn by specifying three points.
Line and Polyline
➢ Use the mouse to select Line. Select a series of points on the screen to define a
zigzag. Note that you can also type and <Return> the ‘x, y’ co-ordinates of a point on
the screen via the Monitor lines. This facility is particularly useful when an Object
needs to be drawn to a specific size or positioned precisely on the screen.
➢ <Return> (right mouse button) to end the line. This escapes from the loop that asks
for more points. The Monitor lines now show that AutoCAD is waiting for a command.
➢ <Return> to repeat the last command (i.e. Line). The use of <Return> in this manner
is commonly used to repeat the previous command.
➢ Select a series of points to (again) define a zigzag.
➢ <Return> to exit the loop.
➢ Try Polyline. Select some points to define a zigzag and <Return> to exit the loop.
➢ <Return> to repeat the last command (i.e. Polyline). Select a series of points to
define a zigzag etc.
Watch the bottom line as it monitors your commands. You will see how Polyline differs
from Line later.
2.2.2 Annotation menu (on Home tab)
Here you can place text on your drawing and add dimensions to specify the size of
Objects. For example,
➢ Select Text – Single Line.
➢ Select a point on your drawing to define the start point for your text. Look at the
Monitor lines.
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➢ <Return> (or right mouse button) to accept the default text height and any other
defaults.
➢ Type in some text at the prompt (use the backspace key to edit the typed entry) and
<Return> twice to end the sequence.
If the text is too small then repeat the sequence, but type in a different height for the text
in, for instance, the Monitor lines. Come back later and try some of the other options
(such as Multiline Text).
2.2.3 Modify menu (on Home tab)
Now there are some Objects in your Drawing Space you can perform a range of
operations to modify/edit them.
The size of an Object can often be changed by selecting and ‘dragging’ one or more of the
grips (‘blues squares’) that appear, but be careful in order to achieve the desired results.
Erase
Use to completely remove Objects.
➢ Select Erase (via the icon). The Monitor lines will prompt you to ‘Select Objects’.
➢ Move onto the screen. Note that you have a ‘Pick Box’ instead of a ‘Cross-hair’ cursor.
➢ Select two lines that you have drawn, these are highlighted.
➢ <Return> to erase all the Objects selected.
Copy
Use to duplicate Objects.
➢ Select Copy. The Monitor lines will prompt you to ‘Select Objects’.
➢ Selecting Objects that you have drawn alters the messages on the Monitor lines and
highlights Objects on the screen.
Select a Circle, note it is selected through a point on its circumference.
Select a Line, note that only one segment of a zigzag is selected.
Select a Polyline, note that the entire zigzag is selected.
If you point at an empty place on the screen then AutoCAD assumes you want to
define a window using a ‘Select Objects Loop’. In this case, if you drag a window
from left to right then all Objects completely enclosed within the boundaries are
selected. By dragging from right to left, all Objects which are at least partially enclosed
within the window are selected.
➢ <Return> to indicate that all the required objects have been selected.
➢ Select a base point (essentially a reference point, e.g. the point on an Object that you
want to specifically position on the drawing).
➢ Move the mouse to drag a copy of your selected Object across the drawing.
➢ Select a displacement (i.e. the point where you want to insert the copy).
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Rotate
Use to move an Object(s) through a given angle.
➢ Select Rotate. The Monitor lines will prompt you to ‘Select Objects’.
➢ Select some of the Objects that you have drawn and then <Return>.
➢ Select a base point and then move the cursor around the screen. The selected
Object(s) rotate according to the cursor placement. <Return> when satisfied with the
new position. Alternatively, a precise angle of rotation can be specified.
Mirror
Use to reflect an Object.
Select Mirror.
➢ Select Objects in the manner already described and <Return>.
➢ Select a start point for the ‘mirror’ operation.
➢ By moving away a ghost of your set of Objects will appear as if reflected about a line.
Select a second point to complete the reflection.
➢ Do you want to keep the original? (Look at the Monitor lines or box adjacent to cursor).
Trim and Extend
Use to remove parts of Objects (including complex shapes) or extend a line.
➢ By way of example, draw a circle with a line across it such that the line touches the
circle in two places.
➢ Select Trim.
➢ Select the line and then <Return>. A ‘cutting edge’ has been defined and this acts as
the ‘blades’ with which the Object (circle) is guillotined. Multiple ‘cutting edges’ can be
selected in more complex situations.
➢ Select one segment of the circle, it is erased.
There is a complimentary command Extend which lengthens an Object to a ‘cutting edge’.
Try experimenting with this command. The ‘cutting edge’ is defined in the same way as for
Trim. The final ‘Select’ extends the chosen Object (most often a line) to the ‘cutting edge’.
2.2.4 Properties menu (on Home tab)
The Properties menu is used, among other things, to introduce new line types (e.g. dashed
and dash-dot) and to alter line thickness.
By default AutoCAD only includes a few line types and others need to be ‘loaded’.
➢ With no items selected in the Drawing Space, select the pull down arrow on the right
hand side of the Linetype option box and select ‘Other…’ to reveal the Linetype
Manager pop-up menu.
➢ Select Load to show all the available line types, choose the required line type and
select OK.
➢ Select OK on the Linetype Manager pop-up menu to return to the Drawing Space.
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➢ To draw an Object that utilises the newly loaded line type, select it in the Linetype
option box and then proceed as normal (i.e. as practised in Section 2.2.1). If the line
doesn’t appear as expected you may need to alter other properties (see later in this
section).
To alter line thickness:
➢ Select an Object in the Drawing Space.
➢ Select the pull down arrow on the right hand side of the Lineweight option box and
choose the required line weight.
➢ If the line thickness of the Object doesn’t appear to change on the screen then check
that the Lineweight button on the Status Line is ON (see Section 2.2.6) and/or zoom
in (see Section 2.2.5).
Many properties of an existing Object can be modified, although the precise options
available depend upon the type of Object selected.
➢ By way of example, select a line.
➢ Click the right hand mouse button and select Properties. A pop-up menu appears
upon which values can be dynamically changed by typing in new entries. Items which
can be changed for a line Object include its type, weight and (linetype) scale; the latter
alters the spacing between, for instance, dots and dashes where a larger value
increases the spacing. Note how the appearance of the selected Object(s) changes
when a value is altered.
2.2.5 Navigate 2D menu (on View tab)
You can imagine a drawing to be set out on a large ‘sheet’, with your view of it being
through a smaller window that is framed entirely by the screen. The ‘sheet’ is not bound
by the size of the screen, nor is the resolution limited to the ‘pixels’ of the screen. Pan
allows you to move the sheet relative to your window so that you see a different part of the
‘sheet’. Zoom, which has multiple options such as All and Window, allows you to change
the size of your window so that you can look at your drawing in greater (or lesser) detail.
Try the following sequences:
➢ Select Pan. Click and hold down the left hand mouse button, and move the drawing to
the required position within the window.
➢ Release the left hand mouse button.
➢ <Esc> to exit the Pan command sequence.
➢ Select Zoom – All. Shows all of your drawing.
➢ View – Zoom – Window. Select two points on your drawing to define a rectangular
window.
2.2.6 Drawing aids – CONNECT YOUR DRAWING CORRECTLY
Snap is the part of the Drawing Space that forces the cursor on to a matrix of possible
positions. With Snap on, move around the screen and notice that you can only point at
certain places on or between the Grid (i.e. the background lines). You can switch Snap
ON or OFF and also change the Spacing – see the Status Line at the bottom of the
screen and Figure 2. The Status Line confirms that Snap (and other Drawing aids) are
ON. You can switch the Grid ON or OFF and you can set the Spacing equal to the Snap
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if you prefer. The Grid is only a visual aid, but Snap affects your cursor. The Grid,
whether on or off, will not be included in a print of your drawing.
Figure 2: Pop-up menu showing example Snap and Grid options.
➢ To alter a setting right click one of the drawing aid buttons on the Status Line (e.g.
Snap) and select Settings; a menu similar to Figure 2 is shown.
➢ <Enter> a different number in the ‘Snap X-spacing’ setting; the ‘Snap Y-spacing’
setting changes automatically to the same value. Select ‘OK’ to exit the pop-up menu.
What can you do with the cursor now?
➢ Experiment in a similar manner with the Grid settings.
➢ The Ortho button on the Status Line restricts the drawing of objects, e.g. lines, to the
horizontal and vertical.
➢ The Lineweight button on the Status Line displays actual line thicknesses in the
Display Space (rather than just the default).
➢ Try switching Snap OFF. What can you do with the cursor now? Switching Snap OFF
can sometimes be helpful for selecting Objects, but is not advisable when drawing.
Apparently well placed lines (as seen on the screen) can give surprises when printed.
It is very strongly recommended that you draw with Snap ON whenever possible.
Frequently it is necessary to connect in some manner an Object to be drawn with an
existing Object. AutoCAD assists this action via Object Snap (OSNAP); see Figure 3.
For example, join the end of a line to the centre of a circle:
➢ Draw a circle (if you don’t already have one on the screen).
➢ Using the mouse, right click the Object Snap button on the Status Line, select
Settings and ensure that the check box Centre is ticked on the pop-up menu that
appears (Figure 3). Ensure that Object Snap is set ON. Select ‘OK’ to close the
menu.
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➢ Select Line and hover the mouse somewhere close to the centre of the circle. The
centre is highlighted and selecting with a left mouse button click starts the line from the
centre of the circle. Select a second point to complete drawing the line.
Figure 3: Pop-up menu showing example Object Snap options.
There are several other options to ‘Centre’ and most are self explanatory. Examples
include ‘Midpoint’, ‘Tangent’ and ‘Endpoint’. Using Object Snap helps to correctly
connect Objects on a drawing.
2.2.7 Saving and printing your drawing
At any time use the Save icon or File menu (‘A’ in top left hand corner) to save the current
version of your drawing. It is recommended to save your drawing every 15 minutes
and at the end of your drawing session that you have at least one independent back-up
copy of your drawing. You have been warned!
To get a printout of the current state of your drawing select Print on the File menu. On the
pop-up menu that appears you will need to select a printer (can also be Adobe PDF).
There are many options on the Print menu, but you can largely accept the defaults. To
make good use of the paper it is recommend to select Extents in ‘What to plot’, tick the ‘Fit
to paper’ and ‘Centre the plot’ check boxes and select the Landscape option in ‘Drawing
orientation’. You are very strongly advised to Preview before printing.
2.2.8 Finishing off and exiting AutoCAD
➢ Select the File menu (‘A’ in top left hand corner) and then Close to exit AutoCAD.
➢ If changes have been made since the drawing was last saved then you will get a
suitable warning. By exiting AutoCAD you will return to the Desktop.
➢ If you have saved to memory stick then remove it. Don’t forget, it is very strongly
recommended that you take a backup (i.e. second) copy of all modified AutoCAD
files before logging off the computer.
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2.3. Expanding your range of commands
There are many AutoCAD commands that have not been described. These are most
useful once you have some confidence. Some are self explanatory and can be accessed
from the appropriate menu. A few examples are:
• Hatch (Draw menu on Home tab). Fills an enclosed area with the pattern that you
select.
• Fillet (Modify menu on Home tab). Allows right angle corners to be ‘rounded’ to a
specified radius.
• Dimension (Annotation menu on Home tab). Allows Objects to be dimensioned in a
consistent style. Most useful with drawings of components.
• Layers (Layers menu on Home tab). By drawing specific groups of Objects in
separate layers (e.g. dimensions, text, construction lines) you can selectively display or
plot any or all of the drawing layers.
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3. INSTRUCTIONS FOR ASSIGNMENT 1 – Hybrid P&ID
Objective
Using AutoCAD, reproduce the drawing shown on Learn.
Guidance
The drawing must be done to a standard which shows that you have mastered the basic
commands of AutoCAD. Primary lines should be wider (ca. 0.7 mm when printed).
Secondary and all other lines should be the default width. Lettering should be of
consistent height and aspect ratio (width to height ratio).
Hints
If you have not used AutoCAD before then you must do the Tutorial (see Section 2).
You may ask relevant questions in computer labs to help you to work effectively. The use
of Snap and Object Snap can ensure that Objects in your drawing are correctly joined.
Remember that you can use commands on the Modify menu such as Trim, Move,
Rotate, Copy etc. to aid drawing production. It will be helpful to initially draw a rectangle
(border) the size of an A4 sheet (297×210 drawing units, 300×210 is close enough).
Requirement
Your drawing needs to satisfactorily convey the information contained in the original. It is
not necessary that details of positioning or scale are exactly identical, however, your
drawing should be well proportioned and make good use of the paper when printed. Note
that it is extremely unlikely that all of you will make the same decisions on where to
position the parts of the drawing – so unlikely that it will be taken as prima facie evidence
of collusion.
Output
Submit your drawing for marking as noted in the Introduction lecture. Include your
name on the drawing, sufficient to distinguish you from others in the class.
Assessment
The indicative criteria for marking the assignment are Proportion (25%), Accuracy (50%),
Completeness (25%).
Notices
• You are expected to attend the supervised computer labs as timetabled and to take the
opportunity to ask for any advice that you need to complete the assignment.
• Remember to save your work at around 15 minute intervals and make a backup copy
of your work at the end of each session.
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3. INSTRUCTIONS FOR ASSIGNMENT 2 – Component drawing
Objective
Using AutoCAD, reproduce the drawing shown on Learn.
Hints
There are features of this drawing that require you to learn how to use other
AutoCAD commands, e.g. Fillet, Dimension and Hatch (see Section 2.3). You may ask
relevant questions in computer labs. It is recommended to fit an appropriately sized
rectangle (border) around the finished drawing. It will repay you to utilise temporary
construction lines and check some dimensions as you proceed with the drawing.
Requirement
Your drawing needs to satisfactorily convey the information contained in the original and
make good use of the paper when printed. It is important that objects are drawn to the
required dimensions. The positioning of the dimension lines and text need not be
identical to those on the original, but they must be unambiguous, uncluttered and all must
be included.
Output
Submit your drawing for marking as noted in the Introduction lecture. Include your
name on the drawing, sufficient to distinguish you from others in the class.
Assessment
The indicative criteria for marking the assignment are Accuracy (75%) and Completeness
(25%).
Notices
• You are expected to attend the supervised computer labs as timetabled and to take the
opportunity to ask for any advice that you need to complete this assignment.
• Remember to save your work at around 15 minute intervals and make a backup copy
of your work at the end of each editing session.

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