QCad/C2/Drawing-Methods-in-QCAD/English

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Title of script: Drawing Methods in QCAD

Author: Leena Mulye

Keywords: CAD, Drawing methods, command, coordinates, QCAD


Resources for recording

QCAD Drawing Methods


Visual Cue
Narration
Show slide number 1

(00-00:08)


Hello and welcome back to another QCAD tutorial.


Drawing methods in QCAD and knowing coordinate system.

Switch to slide number 2

(Cartesian coordinate system) (00:09-00:33)


Qcad uses Cartesian co-ordinate system, which consists of two numbered scales, called as x-axis, y-axis.


These are perpendicular to each other. These axis do divide coordinate system into 4 quadrants.


Your work in QCAD will mostly be in quadrant I


The point where these axis meet is called as absolute origin or the origin point.

Switch to slide number 3

(Lesson Plan)(00:34-00:45)

For this tutorial, I am using the GNU Linux operating system Ubuntu Version 10.04 LTS


and QCAD Community Edition Version 2.0.5.0

Slide number 3

(Lesson Plan)(00:46-00:55)

In this tutorial we will see


Cartesian coordinate system

How to use command line to draw objects

and different drawing methods available in QCAD

Switch to slide number 4

(Drawing methods)

(00:56-4:08)


Switch to QCAD tool->

Let's first see how to use command line to put in co-ordinates to draw points and draw objects of required measurements.


Using the Cartesian coordinate system.


Please have the QCAD application open in your system.


If you want to know how to install QCAD please refer to the earlier tutorial called as 'Introduction to QCAD'.


Which is available on spoken-tutorial website.


Once the application is open from the tool bar on left choose line tool- line with two points.


Now focus on the command prompt, because we are going to use command line to put in exact coordinates.


It is asking to 'specify first point' Let's enter 10 comma 10


We always add x axis value first and then y axis value.


What it is going to do is, it will add a point 10 units away from x and from y axis.


Hit enter. See the point is entered in relation to this origin or absolute 0, 0


Which is 10 units away from x and 10 units away from y axis.


Now suppose I want to draw a horizontal line in this direction, going away from this pint. Say 10 units.


For the next point, I will add 20,10


X-axis value is 20 because, this point the new point will always be in relation to this absolute zero.


So to meet this distance of 10 I will have to add 10 units to the earlier point's X-value.


And Y value will not change so it will be 10 here.


Now if I want to go vertical line downwards again of 10 units


for the next point at the command prompt I will put (showing on application so pause for 4 sec. 2:49-2:53) then say 20,0


X-axis value won't change, Y-axis will be 20 units -ve from the earlier value. So it will be 0.


Now again to go horizontal in 9 O'clock direction for the next point I will put (showing on application so pause for 4 sec. 3:11-3:15) 10,0


Here Y-axis won't change and X-axis will be -10.


In relation to the previously drawn point.


Now to close my drawing I can always put 'c' and hit enter or


I can go back to my original point which was 10,10.


and it will close the drawing. This is how you draw using the command line input.


You can draw any drawing by using this coordinate system by adding, subtracting absolute co-ordinates for any point or vertex between two segments.


Like I did to draw this 10 units.


But this is going to be little complicated.


Rather QCAD offers three easy methods to draw objects with.

Switch to slide number 4

(Drawing methods)

(4:09-6:15)


Switch to QCAD tool->

First is Relative co-ordinates System,


It uses coordinates that are relative to the last point designated, rather than a 0,0 point of the drawing area.


@ symbol is used to enter data using this system.


Lets try drawing this previously drawn square using relative coordinate method.


Let me clear the drawing area


Go to back line tool- Line with two points.


To specify first point at the command prompt enter 10,10- again x and y axis.


It is going to put point at 10,10 distance. For the next point now that we are using relative system we have to put '@' symbol.


Whenever we want to use relative system @ symbol is a must.


After that, I want to draw horizontal line in 3 O'clock direction of 10 units.


So X value is 10 so I put @10,0 because Y value is zero here.


Now for the vertical line going in downward direction, again for relative I use @


Then X value is zero but Y becomes -10 because it is going in opposite direction that is why value is -ve here.


For the next horizontal line in 9 O'clock direction, I say @


Now X axis is -ve, it is going in opposite direction in relation to the previously drawn point. -10,0


Now to close the drawing I can put 'C' and enter.


Or to go back to that original point. This case I say @ 0- X-axis is zero and Y is going in +ve direction so +10.


This is how you draw using relative coordinate method.

Switch to slide number 4

(Drawing methods)

(6:16-8:18)


Switch to QCAD tool->

Next is Relative Polar co-ordinate system


It relies on distance and angle relative to the last specified point.


Always it is +ve and represents distance away from the first point.

Let's try and draw the Previously drawn square using this relative polar coordinate system.


In polar coordinate, right towards towards 3 O'clock is always default zero angle.


All other angles are calculated in anti-clockwise direction related to default zero.


So let's go to line tool – again line with two points


at the command prompt specify first point as 10,10 -Enter. Point is drawn.


Now to draw horizontal line of 10 units using relative polar coordinates. I first put @ symbol because it is relative method.


Then I say distance, I know which is 10


I use this symbol (<)less than symbol “<”for angle


I know angle is in 3 O'clock direction, which is zero. (@10<0)


so my horizontal line of 10 units is drawn.


For the vertical line in downward direction I again put @10<270


and 270 as angle this time because anti-clockwise downward is 270


for the next point horizontal line in 9 O'clock direction


I say @10<180, angle will be 180, as it is exactly opposite to the default zero position.


Lastly I can always put 'c' to close or else enter the point as @10<90, because it is going in upward direction.


This completes our drawing in Polar coordinate method.

Switch to slide number 4

(Drawing methods)

(8:19-11:09)


Switch to QCAD tool->

Third is the Direct distance method


Which can be used to draw lines by specifying first point in relation to already drawn object using snapping tools.


By placing a cursor at that point and entering a distance value.


Let's say in this drawing, if I want to put a horizontal line going in 3 O'clock direction exactly from this point.


I can do so by using this direct method.


I choose line- line with two points

Now I know exactly at what point I want line ahead


so from snapping options on the left tool bar I choose 'snap to endpoint' and then go on that point and left click to select the first point.


Now in relation to this I want to draw horizontal line of 20 units.


So I use command line to specify my next point.


I can use relative polar coordinate system here.


Since it is relative I say @ now distance is 20 and in 3O'clock direction, which is default zero angle so I say @20<0


and Enter. The line is drawn.


Now say I want vertical line of say 7 units going in 90 degrees direction.


I can use now relative coordinate method here.


and say @ (I know 7 is Y direction and X is zero)so 0,7


and I can use relative coordinate method to draw this vertical line.


Again if I want horizontal line going in 9 O'clock direction say 5 units away.


I can again use relative coordinate method.


At the command prompt I say @ -5 now because X value will be -ve comma 0, Y is zero.


Now I can close down this line, because I know the distance is 7


I can draw vertical line going towards 6 O'clock directions


Once I know all the different methods I can draw objects with. I can use combination of any to draw objects.


Now to draw that vertical line, I can use relative polar coordinate.


So I say @I know distance is 7, I use '<' symbol, since it is 6 O'clock direction it is going to be 270


This completes our drawing.


This is how you use different methods in QCAD.

Switch to Slide 5

(Assignment)

(11:10-11:27)

Now that you are familiar with drawing methods and the coordinates system in QCAD.

Lets come to the to the ASSIGNMENT.

[[Image:]]

I would like you to draw diagram as shown in the figure.

You can either use relative coordinate, relative polar, direct method or combination of any method to draw this.

Switch to Slide 6

(Acknowledgement)

11:28-11:45)


I would like to acknowledge the spoken tutorial project which is part of the talk to a teacher project.


It is supported by the National Mission on Education through ICT, MHRD government of India.


For more information on this please visit following website.

Switch to Slide 7

(11:46-11:52)

Thank you.


Hope you are enjoying exploring QCAD


This is Leena signing off.

Contributors and Content Editors

Chandrika

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