Difference between revisions of "QCad/C2/Drawing-Methods-in-QCAD/English-timed"

| Hello and welcome back to another QCAD tutorial.

| Drawing methods in QCAD and knowing coordinate system.

| 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.

| 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

| In this tutorial we will see  

| Cartesian coordinate system

|How to use command line to draw objects  

|and different drawing methods available in QCAD  

| 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 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.

| First is Relative co-ordinates System,

|@ 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.

|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.

| Next is Relative Polar co-ordinate system

|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.

|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

|<nowiki>I use this symbol (<)less than symbol “<”for angle</nowiki>

 

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

|so my horizontal line of 10 units is drawn.

|<nowiki>For the vertical line in downward direction I again put @10<270</nowiki>

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

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

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

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

|This completes our drawing in Polar coordinate method.

|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.

|<nowiki>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</nowiki>

 

|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.

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

|11.06  

|11.10

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

|Lets come to the to the ASSIGNMENT.  

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

| 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.  

|Thank you.

 

|Hope you are enjoying exploring QCAD

|This is Leena signing off.