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FBE
AutoCAD Page |
| This tutorial has been prepared for students at the Faculty of
the Built Environment studying AutoCAD in Communications Seminar
3. It has been placed on the Web to facilitate access by those students
and because I believe others may find the material of use!
While the tutorial is aimed at people using the Windows version of R13, I have (where possible) given the commands to be typed in addition to the toolbar icon. Note that throughout this document I am using the character
" Stephen Peter, 31 July 95. |
 |
|
Introduction |
|
| This church has been selected because it is very symmetrical. Whenever you are drawing anything, look carefully for symmetry and repetition, because CAD systems excel at those things. | In this tutorial you will draw a plan of Brunelleschi's Church of San Maria Degli Angeli (Florence, Italy, 1434-1436), from Clark and Pause's "Precedents in Architecture", page 28; have a look at figure 21 at the end of the tutorial. You will note that the church has eight "bays" and that each bay is itself symmetrical. You will draw half of one bay and then mirror that half to create a whole bay and then copy that to complete the plan... |
|
This tutorial introduces a number of AutoCAD construction
commands:
and a number of AutoCAD editing commands: In case all that isn't enough for you, you will also learn about layers, hatching, and grip editing. |
| Setting
Limits and Units |
|
| You will draw the building in a 50x50m space, but this time, the limits will centre on 0,0! If these seem like particularly perverse drawing limits, it's because they ARE! I'm making sure that you are aware that the limits do not need to start at 0,0. | |
| The coordinates used make the centre of the drawing 0,0 which makes it easy to copy the church "bay" around. |
LIMITS |
Like in the previous tutorial, we need to get rid of the 4
decimal points: select Data - Units, AutoCAD will display
the "Units Control" dialog box. Make sure Decimal
is selected in the Units section and Decimal Degrees in
the Angles section, then in Units Precision, click on the
down arrow beside "0.0000" and select "0",
and finally select "OK". Alternatively, type
UNITS 
and then follow the prompts.
|
|
Zoom All icon  |
To reset the drawing view to the whole of the drawing, select
zoom-all from the standard toolbar (or type: Z [space]
A [space])
|
| Don't forget to do this . . . | Now that you've "zoomed out", draw a rectangle using the coordinates from the drawing limits! |
| Layers |
|
| Most CAD systems have some kind of overlay concept. AutoCAD uses layers. Layers are used to separate and structure drawings; layers can be turned on and off (for example to vary the amount of detail in a drawing), and can have linetypes associated with them.... | |
 Figure 1 The Layer status area of the Object Properties toolbar. |
|
| When you draw in AutoCAD, the graphics appears on the current layer, so once you start using layers, you need to be careful that the current layer is correct. Look near the top-left of the screen: the current layer and it's colour is displayed there. | |
Layers icon 
The same process can be acomplished without the dialog box
by typing: |
Select the Layers icon (or select Data - Layers...),
AutoCAD will display the "Layer Control" dialog box.
Type CONST (it will aprear in the text entry
area at the bottom of the dialog box), press "New",
click on layer "CONST" in the list of layers, click
on "Set Color", select a colour by clicking on it, click
on "OK" to dismiss the set-color dialog box, click on
"Current" to make this the drawing layer, and finally,
click on "OK" to dismiss the layer-control dialog box!
|
| Draw
"Construction" Lines |
|
Line icon  |
Draw a line from the centre of the building, select (or type
LINE
), and then type:
|
0,0 |
|
Zoom
Window icon  |
Before continuing, you should "zoom in" to the lines,
select zoom-window (or type Z
), enclose the lines in the selection rectangle, leave a fair
amount of space to the left and right of the lines. If, after
the zoom, the lines are near the left of the screen and being
obscured by the axis display, use the scroll bars to "pan"
the display.
|
Offset
icon  (look on the copy "flyout") |
Select offset on the Modify toolbar (or type OFFSET
), and then type:
|
| The offset command makes it easy to set up a series of grid line or (drawing) construction lines. | 250
(the offset distance).select the short horizontal line; pick a point anywhere above the line; select the new line pick a point anywhere above it.
(end the command).
This should produce one vertical and three horizontal lines. |
| Revisiting
Polar Array |
|
Polar Array icon  (look on the copy "flyout") Be careful that you don't pick the 3D polar array command . . . |
Now you will use polar array to copy and rotate some lines,
select polar array, type W
(this specifies that you'll draw a selection "window"),
enclose all the lines just drawn in the selection rectangle, press
(to end the selection proces), type 0,0
(for the centre of the rotation), 2
(number of items), 22.5
(angle), Y
(rotate the objects).
|
| The Fillet command that you're using below is exceptionally useful. It basically extends two lines until they meet, and optionally, inserts a curve where the lines join. |  Figure 2 The lines after using Array. |
| Editing |
|
Fillet icon  (from the chamfer flyout). |
The lines at the bottom represent the outside of the building.
To connect these lines select the fillet icon (or type
FILLET
), select the right-hand end of the bottom horizontal line; and
then select the outer of the three sloping lines. AutoCAD will
extend the two lines until they connect to each other.
|
Trim
icon  (be careful - the trim and extend icons are very similar) |
Now you will trim the sloping line back to the line from the
centre, select trim icon from the Modify toolbar (or type
TRIM
), select the right-hand line coming from the centre (see figure
3); press
(to end the selection process), select the line to be trimmed;
and press
(to end the command).
Repeat the fillet and trim process for the two inner lines! |
| The trim command is another
command that you use very often. The first point you specify selects
the "boundary line", that is, the line to which you
are trimming back to. While succeeding points select lines to
be trimmed.
When picking lines to be trimmed, the part of the line that you select is important. In the example in figure 3, if you pick to the left of the first line selected (rather than to the right of it), then the line will be trimmed from the fillet point to the boundary line. In other words, you'll undo the fillet you just did! |
 Figure 3 Points to be selected for the Trim |
| Draw
the floor pattern |
|
| Layer icon |
Before you draw the floor pattern, you'll create a new layer, select the layer icon, create a new layer called FLOOR, and make it the current layer. |
| Line icon |
To draw the horizontal lines of the floor pattern, select line
(or type LINE
), and type 0,-6500
and press
again. This line will be trimmed later....
|
| Offset
icon (look on the copy "flyout") |
Select offset (or type OFFSET
), type 625
(the offset distance), select the line just drawn, click below
the line to indicate the direction of offset, and press
again. Press
(to start another offset), type 1375
(offset distance), select the last line created by the offset,
click below the line to offset down, and press
again to end the command.
|
| Remember that you can restart
the last command by pressing
Keep watching the command line area and follow the prompts. |
Offset this line 625 down! If that worked,
you should have two pairs of lines. These lines will form the
octagonal pattern in the centre of the building. Continue offsetting
the "last" line, using the following offsets:
|
| That's most of the horizontal lines in the plan! Next, you will now draw the rest of the floor pattern. Have a look at figure 17 which shows the completed bay. | |
|
Trim icon
I'm introducing the "fence" option because it makes it very easy to trim a whole series of lines by simply drawing a line that crosses them. The fence line works like the "crossing window" selection in that the objects that the line crosses are selected. |
Firstly, offset the vertical (centre) line 2000 to the right,
and then select : trim (or type TRIM
), pick the vertical line just created pres
(end the selection process), type F
(this tells AutoCAD that you will draw a fence line
- see figure 4), draw a fence line like that shown in the figure
(it must cross the four lines shown), after you pick the
second point of the fence line, pres
twice (firstly to end the fence line and secondly to end the command)!
|
 Figure 4 Trim "fence" line. |
|
Erase icon  Redraw icon  Save icon  |
Select erase from the Modify toolbar (or type E
), select the vertical line used as the "trim guide",
press
(end the command). If the drawing view looks messy (with blips)
select redraw (or type R
). Now is a good time to save the drawing, select save (or type
QSAVE
), enter a drawing name if prompted (and don't forget to change
the drive & directory if necessary).
|
| Line icon Endpoint snap mode icon  |
Now you will draw the line and arc floor pattern, select line
(or type L
), choose the Endpoint snap mode (or type END
) select the right edge of the "bottom" trimmed line,
choose the Endpoint snap mode again and select the right edge
of the line above it, then press
(end the command).
|
 Figure 5 "Center-Start-End" Arc icon on the Arc flyout. |
|
Midpoint snap mode icon  |
Select the "Center-Start-End" Arc (shown in figure
5), using the Midpoint snap mode select the middle of the line
just drawn, then type @0,-1800 .
That should have drawn an arc to the right of the vertical line.
|
 Figure 6 "2 Points Select" Break icon on the Break flyout. |
|
| Break is an extremely useful command that is used often in editing operations. | Now you will use "break" to remove the part of the
line between the arc's endpoints. Break is an extremely useful
command that is used often in editing operations. Select "2
Points Select" Break (see figure 6), select the vertical
line that you drew a minute ago, then using the Endpoint snap
mode, select the bottom end of the arc, and finally using the
Endpoint snap mode again, select the top end of the arc.
Now draw a line (using the Endpoint snap mode) joining the two other trimmed lines (see figure 7). Then trim the four horizontal lines towards the centre of the bay, back to the right-hand edge of the "bay". |
 Figure 7 Zoom Window |
|
| Zoom Window icon |
The last floor pattern is at the top of the "bay".
You will need to enlarge the view of the centre to be able to
see it clearly. Select zoom-window (or type Z
), enter the selection window shown in figure 7 (above).
|
| Line icon Endpoint snap mode icon |
Select line (or type L
), and then type 0,-600
), then using the Endpoint snap mode, pick the right-hand end
of the top horizontal line below, finally press
to end the command.
|
 Figure 8 Lines drawn prior to grip editing |
|
Intersect snap mode icon  |
Now you will use a technique in AutoCAD called "grip-editing". Click on the two lines just drawn, they should turn purple, then click on the intersection point of the lines (the intersection should become red), select then Intersect snap mode, click on the position where the horizontal line crosses the right-hand edge line. AutoCAD should move the selected vertex to the intersection point! Press the Escape key (ESC) twice to de-select the lines. |
| Zoom
Dynamic |
|
 Figure 9 Zoom Dynamic |
|
One of the most powerful of the zoom options is zoom- dynamic,
it allows for zooming and panning at the same time. Type
Z
or select the command from the zoom flyout (flydown?) shown in
figure 9.
AutoCAD should draw the whole drawing, a purple rectangle showing the current view and the cursor will turn into a rectangle with a X cross at the centre. If you click with the left mouse button you can resize the zoom window's size (click again to fix the new size). Move the zoom window (the cursor!) over the lower half of
the "bay" and press |
|
| Draw
the Walls |
|
| Before drawing the walls, create a new layer called "WALLS", and set the layer's colour to be something other than white, and make it the current layer. | |
| Don't forget to offset the line at the "top" of the arc (see figure 10) | The wall is 700 outside the arc floor pattern, so we will offset that pattern. Offset the arc and the vertical lines on either end (to the right) by 700. Notice that the new lines are in the floor layer, you will need to change the lines into the walls layer. |
properties
 |
Select properties (from the right end of the Object Properties
toolbar), type C
(this tells AutoCAD that you will create a "crossing"
selection rectangle), enclose the arc and the lines below it in
the rectangle, then select the line that was offset from the line
at the top of the arc (see figure 10); press
(end the selection process), select "Layer...", select
WALLS (the new layer), and finally select "OK".
|
 Figure 10 Change properties selections |
|
| Fillet icon |
Now you will join up the sections of the wall line outside
the arc. Select fillet (or type FILLET
), select the bottom of the short vertical line and then select
the horizontal line to the left of the vertical line (see figure
11).
|
| In selecting both these points, it's important where you click on the line! The first point should be in the bottom-half of the line, while the second point should be to the left of the (projected) first line. |  Figure 11 Fillet points |
| Now, use fillet on the lines shown below (see figure 12). Note that the extact position that you pick is not important, >but, it is important that you pick to the right (1st point) and below (2nd point) the intersection, the part you pick (at this stage of the fillet command) is the part that AutoCAD will not remove! | |
 Figure 12 Second Fillet points |
|
| Save
icon |
That completes the bottom end of the bay. Have you saved your
drawing recently? If not, then save it!
Now use the scroll bars to move the view so that you can see more of the lines at the "top" (you need to be able to see the area shown in figure 13). |
|
Offset icon (on the copy flyout of the Modeify toolbar) |
Select offset (or type OFFSET
), and then type 250 ,
pick the bottom of the four lines that extend to the right edge-line,
pick a position below the line to indicate the offset direction,
press
to end then command.
|
| Fillet
icon |
Now you will use fillet to clean up the rest of the wall lines.
Select fillet (or type FILLET
), pick the short vertical line (see figure 13), and then pick
the right-hand end of the line just created.
|
 Figure 13 Third Fillet points |
|
| Restart the fillet command, pick the outer arc to the right of the vertical, and pick the vertical above the arc. | |
| Properties icon |
Change the horizontal line ("2nd pick" in figure 14) into the WALLS layer (use change properties). |
 Figure 14 Extend. |
|
Lastly, you will extend the horizontal line to the right edge-
line. Select extend see figure 13 (or type EXTEND
), pick the right edge-line (this is the line you will extend
to), press
(end the selection process), pick to the right of the middle
on the horizontal line, and finally press .
You need pick to the right of the middle of the line because AutoCAD
extends the nearest endpoint to the "boundary edge".
|
|
| Draw
the Passage Between the Bays |
|
| Use the scroll bars to bring the bottom into view.
To draw the passage-way we will firstly draw its centre line, and then use offset to get the location of the walls. |
|
| Line icon Center snap mode icon  |
Select line (or type L
), select the Center snap mode, pick one of the arcs, type
@3000,0
(to show the direction of the line), press
(to end the command).
|
| Offset
icon |
Select offset (or type OFFSET
), and then type 500 ,
pick the centre-line, pick below the line, pick the centre-line
again, pick above the line, press
(to end the command).
Extend the bottom line to the right edge-line! |
| Intersection
snap mode icon Perpendicular snap mode icon  |
Select line (or type L
), select the Intersection snap mode, pick the intersection of
the outer arc and the top-most of the 3 lines; select the Perpendicular
snap mode, pick the right edge-line.
Erase the top two horizontal lines, and trim the bottom line back to the outer arc. Finally, use Break (2 Points Select), to remove the section of arc between the walls of the passage. |
| Finishing
the Walls! |
|
Layer visible icon 
|
Before hatching the wall areas(!) you will need to close off the walls. Firstly, you'll turn off the CONST layer. Click on the layer status area (see figure 15), AutoCAD will display a list of the layers and their status. The fourth icon controls whether the layer is visible. Click on this icon beside CONST, the eyes should close! Then click on WALLS to close the drop-list. |
 Figure 15 Layer display |
|
Running object snap icon  |
When you need to use a snap mode repeatedy, you can define
a "running snap" - this allows you to use the snap mode
whenever you pick a point. Select Running Object snap from the
Object Snap toolbar (AutoCAD will display a dialog box), select
"Endpoint" and then "OK". Alternatively you
can type OSNAP .
|
| Now draw the lines (see figure 16), you may need to use zoom or the scroll bars to get all the lines in the view. These lines are needed because you must close off areas before hatching them. | |
| Running object snap icon |
Once you've drawn the lines, turn the auto-snapping off by
selecting running snap again and then clicking on "Clear
All" (or type OSNAP
).
|
 Figure 16 Lines to close of hatch areas. |
|
| Hatching |
|
| Save icon |
Before hatching it's often a good idea to save your drawing
(select save or type QSAVE
). Hatching can crash AutoCAD.
|
Hatch
icon  |
Create a new layer, called hatch, and make it current, and
then select hatch from the Draw toolbar, make sure the pattern
type is "Predefined", and set the patern (in Pattern
Properties) to AR-SAND (click on the down-arrow), set the
scale to 50, select "Pick Points", pick inside the two
areas, press
to end the selection process, pick "Apply". AutoCAD
should draw lots of dots, almost filling-in the wall area.
Finally, you need to erase the three lines you added to close
the wall areas so you could hatch them (see figure 16). Use
the Layer Controls to turn the "HATCH" layer OFF first.
If you accidentally pick the wrong thing, type: That completes the basic half bay! Use zoom dynamic to view the whole of the bay and then save your drawing! |
 Figure 17 Completed Bay |
|
| Mirror
the Half Bay |
|
To mirror the section completed, select mirror from the copy
flyout (see figure 18), type W ,
enclose all the graphics inside the selection rectangle, press
(to end the selection process), type 0,0
(the centre of the building will be the start of the mirror line),
type @0,-1
(this creates a vertical line as the mirror line, this causes
the graphics to be mirrored to the left), type N
(don't delete the old objects).
|
|
 Figure 18 Mirror - Copy Flyout. |
|
| Duplicate
the Bay |
|
| Zoom
All icon Polar Array icon |
Before continuing, do a zoom-all (select Zoom All or type
Z
), so you can see the whole drawing. Then select polar-array from
the copy flyout, type W
(selection "window"), select the whole bay, press
(end selection process), type 0,0
(rotation centre), 8
(we want 8 bays!),
(go all the way), Y
(rotate as you go). AutoCAD will copy the single bay through 360
degrees, giving 8 bays!
Save the drawing!! The drawing is now about 3 megabytes so it might take a little while to save. |
| Last
Gasps.... |
|
| That's basically it, except for the doors! There are a few
other details (such as a spiral stair) that we won't draw, but
we will draw the entry - this will give you some experience erasing
hatching...
Zoom in on the "eastern" bay (see figure 19). If
AutoCAD didn't draw the hatching type |
|
 Figure 19 Zoom in to locate Entry |
|
| Line
icon |
You will now draw the centreline of the doorway, select (or
type L
), select the Endpoint snap mode and pick the middle of the inner
vertical wall line, then select the Perpendicular snap mode and
pick the outer vertical line of the wall (the line to the right
of the one just picked).
Next, offset the line 1250 "up" and "down" to make a 2500 wide doorway; and erase the centre-line. |
| Trim
icon |
You will now use trim to take the vertical two lines back to
the doorway line. This is done because we want to hatch the wall
area again, so can't have any lines "sticking out".
Select trim (or type TRIM
), pick the doorway lines, press
(end selections), pick the vertical lines (see figure 20); and
press
(end the command).
|
 Figure 20 Vertical Lines to be trimmed. |
|
| Draw the lines back(!), but as two lines, instead of the four.
We could draw the door, but let's not bother!
Now you need to draw two lines to close off the two hatch
regions. If the hatching is not visible type |
|
 Figure 21 Lines to Join. |
|
| Now hatch the four areas! | |
 Figure 22 The completed drawing |
|
| The entry has number of stairs and there is another entry on the "western" side but we'll leave that off! | |
| Zoom All icon Save icon |
Select Zoom-all (select or type Z
), so you can see the whole drawing (see figure 22). Save your
drawing (select save or type QSAVE
). Exit AutoCAD and logoff! |
 FBE
AutoCAD Page |
2D-R13
Tutorial 4 |
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| Last
Update : 8 April 2000 Major Revision : 29 October 1997 SEARCH . FBE SITEMAP |
 
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Disclaimer
. Webmasters Page Contact : Stephen Peter Email : s.peter@unsw.edu.au |