how to draw a plane?

Hai,

I am working on optics. I have plotted a lens in matlab. The rays of light emerging out of the lens, after undergoing refraction in the lens, needs to be projected on a square plane in front of the lens. How is it possible to draw a plane in matlab? Looking forward to hearing from you soon.

BSD

Answer 1

[Walter Roberson]

You can use patch() to draw a shape embedded in 3D.

[bsd]

I gave the command patch([0,0] [0,1] [1,1] [1,0]), it is showing an error "unbalanced or unexpected parenthesis or bracket". The above points are the coordinates of a square plane in 2D.

BSD

[Fangjun Jiang]

You forgot the comma.

patch([0,0], [0,1], [1,1], [1,0])

[bsd]

I added the comma, it is not showing error. But only a line from the point (0,0) to (0,1) is displayed, other lines of the square is not displayed.

BSD

[Fangjun Jiang]

See doc patch for examples.

[Walter Roberson]

All of the x data must be together, and all of the y data must be together.

patch([0 0 1 1 0], [0 1 1 0 0], [0 0 0 0 0])

Notice I have provided z coordinates here, to make it a 3D patch in order to make it a plane as was required by the original question. If all that is required is a 2D square then you could use rectangle() instead.

[bsd]

http://www.opticasoftware.com/documentation/Rayica/PrinciplesOfRayica/4Customization/index.html#.1.2

go to the above link, and see the figure just immediately above the section 4.3. This is what I want to do using matlab, after the rays emerge out of the lens, and they hit an aperture in front of it, as seen in the above figure.

[Walter Roberson]

Yup, you will be wanting non-zero z for that. The basic call will be as I gave above, patch([0 0 1 1 0], [0 1 1 0 0], [0 0 0 0 0]), but you will want different coordinates. The first parameter is a list of the x coordinates, the second parameter is a list of the corresponding y coordinates, and the third parameter is a list of the corresponding z coordinates.

You will also want to create a patch() for each of the apertures. You can use the usual sin() vs cos() coordinates if your square is perpendicular to one of the axes. For example,

sides = 17;

radius = 3;

angles = linspace(0,2*pi,sides+1) .';

coords = [radius * sin(angles), zeros(size(angles)), radius * cos(angles)];

xoff = 5; yoff = 2.8; zoff=3.3;

patch(xoff + coords(:,1), yoff + coords(:,2), zoff + coords(:,3));

and to draw the next circle, just change the xoff, yoff, zoff, and repeat the patch() command.

Answer 2

[Sean de Wolski]

You could also use a surf or a slice

[Walter Roberson]

If your plane was along the z axis, then surf would not be able to handle it, as surf requires unique (x,y) for every z value.

Answer 3

[Adam Danz]

Starting in MATLAB R2024b, you can use constantplane to create a 2D plane in 3D axes. However, unlike surfaces and patches, the ConstantPlane will extend infinitely in all directions within the axis limits.

For example, to create a flat plane along the z axis at z=0,

constantplane('z',0)
grid on

[DGM]

Finally! This is the logical extension of xline() and yline().

[Matt J]

Looks like they also fixed the plane-plotting bug in fimplicit3 mentioned here.

load data E C ax
planefun=@(x,y,z) E(1)*x+E(2)*y+E(3)*z+E(4);


plot3(C(1), C(2),C(3),'rx'); axis(ax); hold on

fimplicit3(planefun,ax,EdgeColor='none',FaceAlpha=0.5); hold off