How To Create An Animation In Matlab

Animation is a series of still images i subsequently another. If you show these images together in rapid succession, the brain interprets them equally continuous fluid motion.

The animation follows a similar workflow to that of creating a flip-flop volume. A flip-bomb book is a booklet with a series of images that gradually change from one page to the adjacent.

When you view the pages quickly, the images appear to animate past simulating move or some other change. Blitheness has a broad advantage and is widely used in the science and engineering field. It helps to bring ideas into real-life or give the context of the idea.

In this article, we will look at how you can create an animation using Matlab. Nosotros will as well expect at the various steps involved and use the Matlab inbuilt functions to make the activeness simpler.

Prerequisites

To follow along with this tutorial, you will need:

• Matlab installed.
• Proper understanding of MATLAB basics.

Animation in Matlab follows a workflow like that of creating a flipbook. The steps involved in creating an animation in Matlab are as follows:

1. Run a simulation or generate data.
2. Draw/return the scenario at some time t_k.
3. Take a snapshot of the scenario.
4. Accelerate time t_k to t_(k+1).
5. Saving the movie.

Note that you take to repeat steps 2 to four to keep going through edifice one frame or one folio in the flipbook 1 at a time and saving information technology to the large flipbook earlier proceeding to step 5.

Matlab functions that tin can be important at each of the steps

1. Run a simulation or generate a information

Maybe you lot accept a fancy flight simulator that will run a scenario, kick out all this data, and save it to a file. So all y'all need hither is to load the data. It means that You apply the load function here. Also, if y'all are familiar with Simulink, yous know that yous can run a Simulink model from a Matlab script to generate information using the sim function.

2. Drawing/ rendering the scenario at some bespeak t_x

This deals with plotting or drawing ane single frame of the blitheness. It means that you will use the plot functions such as plot, plot3, surf. A couple of things that tin be helpful include the hold on function for complicated scenarios or animations. Besides, information technology helps to draw many figures on the aforementioned plot. Because of jamming the plot office inside the for loop, you have to periodically wipe the slate make clean afterwards every time. In this, we utilise the clf part.

3. Take a snapshot of the scenario

Once you have drawn one page of the flipbook, nosotros want to grab that frame and salve it into the large flipbook. Matlab has the function become frame for doing this.

4. Advance fourth dimension tone thousand to t(m+1)

Like we said earlier, If nosotros put the process inside a for loop or a while loop, the pace is automatically handled. If you have data that you lot are simulating that is very temporally timely spaced, you might take tons of data.

You may non want to plot every single bespeak of your data since that will exist a very dense motion-picture show. So nosotros will implement the logic of skipping some data and using the continue function for this.

5. Saving the motion picture

To salvage the picture show, we will utilise VideoWriter and WriteVideo functions.

Instance

We desire to breathing the trajectory of a signal. Let us say we run some simulations or accept some equations that generate the trajectory at some betoken in the space. The position vector describing where the indicate is located at any given x, y,z location given fourth dimension t is:

$$ r(t)=\begin{cases} 10(t)=5cos(t)\y(t)=2sin(t)\z(t)=t\cease{cases} $$

The range of t is from 0 to 2pi. If you expect at that position vector long enough, you lot will run across that it describes the particle moving in the upward elliptical single helix.

Implementation in Matlab

We create a script file for this and do the normal clearance of the workspace and the command window.

                          %Analogy of animation using Matlab              clear clc articulate all                      

Now let usa piece of work through the v steps. As we said earlier, the time is going to go through from 0 to 2*pi and we will utilise 100 points for this.

Stride 1

To generate 100 equally spaced points, nosotros employ the linspace office. We also define our x, y, and z positions.

                          %% step 1: generate plot              t = linspace(0,              2              *pi,              100); x =              5              *cos(t); y =              ii              *sin(t); z = t;                      

Pace 2

We so showtime a new effigy using figure functions and use a for loop to extract data at the current fourth dimension.

                          %% step2: Draw/return the scenario              effigy              for              k =              1:length(t)              %extract information at the current time              t_k = t(k); x_k = x(k); y_k = y(k); z_k = z(thou);                      

And then that is the electric current location of the particle. Allow the states go ahead and plot this current location.

                          %plot the current location of the particle              plot3(x_k, y_k, z_k,              'become',              'LineWidth',              iii,              'MarkerSize',              15)                      

Footstep 3

To draw the entire trajectory, we execute the code below:

                          %plot the entire trajectory              hold on plot3(x,y,z,              'b-',              'LineWidth',2)                      

Let's add the title and the labels to our plot and set the viewpoint.

                          %decorate the plot              grid on xlabel('ten') ylabel('y') zlabel('z') title(['particle at t=', num2str(t_k),              'seconds'])  view([30              35])                      

Let us run the script and run across what we have at this point.

We noticed from the prototype above that Matlab plotted all the points because we had the hold on office that kept on plotting and plotting.

One of the things that nosotros need to do is to make a change. Our expectation is not to plot all the points but to have a point moving on the spiral. At present let u.s. wipe the slate clean and so that every fourth dimension we are plotting, it is on a blank figure.

Step 4

To do this, add together the code below after the thousand=length(t) so that we have:

                          for              k =              1:length(t)              % wipe the slate clean, and so we are plotting with a blackness figure              clf                      

If we run the code now, nosotros volition accept:

Surprisingly, this, besides, didn't work. As nosotros can see, information technology ended up drawing the very last paradigm hither, which is not what we expected. What we look is a particle moving up a spiral. It did not happen because Matlab noticed that our plot control was within a for loop.

Matlab is smart to realize that it volition slow down if information technology draws every single image here in this loop. So information technology suppresses the plotting until you drib out of the loop and and so render the very concluding seen.

Since that is not the behavior we demand hither, we will strength Matlab to draw the image. Nosotros do this by using the drawnow function. This function forces Matlab to affluent the graphics to plot this as it goes.

                          % Forcefulness Matlab to draw the prototype at this bespeak              drawnow                      

Let united states now run the lawmaking:

Now it seems reasonable. Or, we can apply the pause office. This function takes the pause fourth dimension every bit the statement.

            suspension(0.ii)              %Information technology pauses for 0.2 seconds and continues                      

What we are doing at present is watching flipbooks occur one fourth dimension on our screen. This isn't exactly what we would similar to do hither because nosotros want to salve the flipbook.

Let the states call the getframe function to force the graphics to render and return a bitmap or matrix of the values of the current figure. This function works as the drawnow part.

Annotate out the drawnow and have the code below:

                          % Force Matlab to draw the image at this point              % drawnow              movieVector = getframe;              stop                      

When we run this program, every time it hits a point, it will grab the current picture and jam it into the variable movieVector. Thus, you will come across a vector movieVector in the workspace when the programme has completed running.

Step 5

The terminal step is saving the movie. Nosotros have a picture vector which is all our flipbook. Nosotros need to print it out as an actual .mp4 file. We use a videoWriter function that Matlab uses to practise a lot of video writing operations. The argument for this part is the name of the movie and, in our case, bend.

                          %% Save the movie              myWriter = VideoWriter('curve');                      

Now, let's go ahead and change the parameter, east.g. frame charge per unit

            myWriter.FrameRate =              20;              %movie to play at 20frames per second.                      

We now demand to open the video writer, write the movie, and close the file.

            open up(myWriter); writeVideo(myWriter, movieVector);              %It generates a .avi video and saves it in your drive.              close(myWriter);                      

To locate your file, you look at the current folder in Matlab and locate it on your device and play it. In instance your device cannot open a .avi file, there is an alternative for this. The alternative is specifying .mp4 to the videoWriter role, as shown below:

            myWriter = VideoWriter('bend',              '');                      

Conclusion

Matlab provides a better surround for performing the animations because of the in-congenital functions that makes this process quicker. Besides, Matlab is very smart and performs specific operations automatically.

These operations are such every bit data generation. Movies and animations can be performed for more than complex operations in the field of science. It helps to visualize the ideas in the field of science.

I promise this tutorial helps you create movies and animations using Matlab. Happy coding.

---

Peer Review Contributions by: Dawe Daniel

Source: https://www.section.io/engineering-education/creating-movies-and-animations-using-matlab/

Posted by: pettitsuded1943.blogspot.com

Share this post