QCad/C2/Modification-Tools-to-Scale-and-Rotate/English

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Title of script: Qcad-Modification Tools - Scale and Rotate two

Author: Leena Mulye

Keywords: video tutorial, QCAD, Scale, Stretch, Mirror, array, rotate


Click here for slides

Click here for tex files


Visual Clue
Narration
slide 1

(00-00:03)

Hello and welcome to this spoken tutorial on Using

Modification tools to scale and rotate in Qcad.

Switch to Slide 2

(00:04-00:25)

In this tutorial we will see modification tools as

Scale

and Rotate two

For this tutorial, I am using GNU Linux operating system Ubuntu Version 11.10 LTS

and QCAD Community Edition Version 2.0.5.0


Switch to QCAD application window

(00:26-2:10)

I assume that you know how to use Qcad, If not then please refer to our earlier tutorials available on spoken-tutorial site.

Let us start with Scale tool.

Open QCAD application.

In my QCAD application, I have set the units to meters, and grid size to 0.01x0.01.

Let us draw a rectangle first, go to line tool and click on rectangle icon.

Choose snap to grid option. Zoom in drawing area using middle mouse button if grid is too small.

Left click on the grid for first corner and second click to complete rectangle. I am choosing 4 grids for width and 6 for length.


Let us start with Scale tool.


Open QCAD application.


In my QCAD application, I have set the units to meters, and grid size to 0.25x0.25.


Let us draw a rectangle first, go to line tool and click on rectangle icon.


Choose snap to grid option.


Zoom in drawing area using middle mouse button if grid is too small.


Left click on the grid for first corner and second click to complete rectangle.


I am choosing 4 grids for width and 6 for length.


So my rectangle is of size 10x15.

Use Scale tool Scale tool enlarges or reduces object but keeps proportions same after scaling.

We will dimension this rectangle to see that.


Go to top menu dimension->I will choose horizontal.


And then dimension this rectangle by choosing end points.


Now we will use scale tool on this rectangle.

Go to top menu->modify>scale


or you can choose it from tool bar.

click on edit -> scale icon here.

QCAD_Scale_Rotate.pdf

We need to select the object.

For this we can left click on each line then click on an arrow to continue.


From snapping options we can choose intersection of these lines.


In the pop-up window let us 'keep original'.


Factor for scaling - 2 so that it will create rectangle double of this size.

Now click "OK".


Let us dimension the scaled rectangle and see.


So it has created a rectangle double of original size.


Using scale tool, depending on factor of scaling, you can either enlarge or reduce objects proportionately.

Check Rotate-two tool

(7:14-10:16)

et us see rotate two or counter-rotate tool.

Using rotate two we can create array of objects in circular direction.

For demonstration purpose I will draw a circle with an object inside.

To draw circle go to tools and choose -circle icon. I am selecting circle with centre and radius. Radius is 30.

Now select horizontal line tool from tool bar, draw line of length say 50, select start point as middle and snap to centre of the circle.

Now select vertical line and draw line perpendicular to previous Drawn line of same length.

I will draw another circle of radius-4 somewhere on this line. Select snap to closest point on entity.

And will draw two lines tangent to this circle. Using line tool->tangents from point to circle option.

Select point using free positioning and orthogonal option

and click on circle for tangent point. Similarly draw the other line.

Now say I want to create 4 copies of this object going in circular direction, inside this circle.

Let us select rotate-two tool.

Go to modify-rotate Here this rotate tool can create single or multiple rotated copies of an object.

Move and rotate will let you rotate objects with specified distance and create multiple copies.

This Rotate, is the one I want to use, If I want objects to copy in circular direction around a point.

To select object, use 'select window' option from left bar here.

Now left click outside the object to start window then hold left mouse button and drag and release after selection is done.

Click on arrow to continue.

I have to specify 'absolute reference point' - this is to set centre of rotation for the main object around which these objects will rotate.

So that will be centre point of this big circle. From snapping options choose snap to centre points. Left click to select this point.

Next is to specify relative reference point- This is to set centre of rotation for individual objects.

For this I will give, centre point of this circle, which is an object I want to create copies for.

From the pop-up option window, I can either delete original or keep original, make multiple copies.

As I want to make 4 copies, I will select keep original and write 3 for copies. So this will be the 4th one at an angle 90.

There is another angle 'b' we will see that next. Let's not put any value here.

Now click Ok, It has created array of similar objects going around in this direction at given angle.

Notice the object is also rotated at that angle.


Rotate-two tool with angle 'b' option. We will now see how the angle 'b' option works.


This is used when we want to rotate multiple copies of this object around a center without rotating the objects themselves.

or rotate the object around itself with another angle than the angle for main rotation.


Let's copy this and move to space here.

Select copy, point is centre of this circle and move to grid somewhere here,

left click to confirm.


I will keep one object and delete the other three, by selecting them using drag option

then go to modify-delete selected.


Now to see option 'b', We will use rotate-two.

This tool can also be accessed from left tool bar, using this icon.


Let us select this object by select window option.


For absolute reference point I will give as centre of this circle.


Next the relative reference point will again be centre of this circle.


Let's say we want 6 copies, so I will put 5 here and select keep original.

Angle will be 60 for 6 copies around 360 degree.


Now since I do not want objects to rotate around themselves,


I can give option b' as -60.


The angle 'b' works in anti-clockwise direction, -60 will make it 0.


Click 'ok' here, now see the difference since I had given angle 'b' as -60 it has become zero.


And objects are arrayed in circular direction but without the rotation for the individual objects.

Switch to Slide 4

(Assignment)

(10:17-12:08)

Now the assignment part..


I would like you to draw following using tools learnt in this tutorial.


File:Qcad5 assignment.pngLet's see it in detail window here.


For scale tool draw rectangle of size 40x60, Scale it so to half the size.


Now for the rotate-two, draw circle of radius 30. Draw two lines going through centre of circle of length 50.

At the end of the line, draw rectangle of 4x8, draw middle line to get centre of rectangle.


Using rotate-two command to rotate this rectangle to get 10 copies.


Next you can try the angle-b so that rectangle is rotated around main circle's centre but not around itself.


The end result should look like this.

Switch to Slide 5

(About Spoken Tutorial Project)

The video available athttp://spoken-tutorial.org/What_is_a_Spoken_Tutorial

summarizes the spoken tutorial project If you do not have good bandwidth, you can download and watch it

Switch to Slide 6

(About Spoken Tutorial Project)

* We conduct workshops using spoken tutorials We also give certificates for those who pass an on-line test 
Please contact us for more details
Switch to Slide 7

(Acknowledgement)

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.

http://spoken-tutorial.org/NMEICT-Intro

Switch to Slide 8 Thank you.


This is Leena from IT for Change from Bengaluru signing off.

Contributors and Content Editors

Chandrika, Nancyvarkey, PoojaMoolya

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