Solved

Compound matrix transformation [code attached]

Posted on 2008-10-09
3
678 Views
Last Modified: 2013-11-25
Hello Experts,

I have the following code which shows the rotation of a 2D polygon and what i want is to modify it using a compound matrix transformation so that the square rotates about an arbitrary point.

Can anyone help me how can i do such a thing ??

Thanks in advance
close all;

clear all;

 

 

% a 2D pologyon 

p=[-1 1 1 -1 -1 ; -1 -1 1 1 -1];

 

% points p = in homogeneous coord

p(3,:)=1;

 

% axes for plotting the animation

figure; 

hold on;

axis([-6 6 -6 6]);

axis equal;
 

for theta=0:0.005:2*pi
 

    R=[cos(theta) -sin(theta) 0 ; sin(theta) cos(theta) 0 ; 0 0 1];

    

    pdash=R*p; 

    

    pdash(1,:)=pdash(1,:)./pdash(3,:);

    pdash(2,:)=pdash(2,:)./pdash(3,:);

    

    cla;

    plot(pdash(1,:),pdash(2,:),'b');   

    drawnow;

    

end

Open in new window

0
Comment
Question by:perdoname_
3 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 22694376
0
 
LVL 4

Accepted Solution

by:
SyfAldeen earned 500 total points
ID: 22895982
perdoname_,
Here you are the modified code:
You can learn more here:
Transforming Objects - MATLAB

function rotsquare

close all;

clear all;
 

% a 2D pologyon

p=[-1 1 1 -1 -1 ; -1 -1 1 1 -1];
 

% points p in XY plane

p(3,:)=0;
 

% points p = in homogeneous coord

p(4,:)=1;
 

% axes for plotting the animation

figure;

hold on;

axis([-6 6 -6 6]);

axis equal;
 

%Rotate about the upper right corner (1,1)

Tx1 = makehgtform('translate',[-1 -1 0]);

Tx2 = makehgtform('translate',[ 1  1 0]);
 

for theta=0:0.005:2*pi

    R=makehgtform('zrotate',theta);

    pdash=Tx2*R*Tx1*p;

    cla;

    plot(pdash(1,:),pdash(2,:),'b');

    drawnow;

end

Open in new window

0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Vertex form of the function 8 66
word0 challenge 3 78
PHP question(s) about order of output 9 57
Advice in Xamarin 21 57
How to remove superseded packages in windows w60 or w61 installation media (.wim) or online system to prevent unnecessary space. w60 means Windows Vista or Windows Server 2008. w61 means Windows 7 or Windows Server 2008 R2. There are various …
If you haven’t already, I encourage you to read the first article (http://www.experts-exchange.com/articles/18680/An-Introduction-to-R-Programming-and-R-Studio.html) in my series to gain a basic foundation of R and R Studio.  You will also find the …
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.

895 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now