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Plot 2D/3D region

version 1.1 (10.9 KB) by

The program plots convex closed regions in 2D/3D.

27 Ratings



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Editor's Note: This file was highlighted in the File Exchange Pick of the Week blog.

The program plots convex closed regions in 2D/3D. The region is a subset of R2 or R3 such that Ax>=b and lb<=x<=ub. It is also possible to plot points in the same plot.

(See help plotregion for more documentation)

Comments and Ratings (30)


Ganesh (view profile)

Sarah Sachs

Sirvan Ahmadi

Sirvan Ahmadi

I need to plot the following region. Is there any way to plot it with this package?

a=0: 0.1 :1;
b=0: 0.1 :1;

y+x <= k(a,b);

where f, g, and k are nonlinear functions.


Andy Andy


lufei (view profile)

very good


Hristo (view profile)

Excellent package - works like a charm and gets you experimenting in a second!


Nan (view profile)

Is there anybody could tell me what the meaning of


answer to song:
ax<=b is euivalent to -ax>=-b


Song (view profile)

It is very helpful to me. As a beginner for Matlab, I have a question which is how could I modify the program to Ax<=b. Can you help me on it?
Thanks in advance


Xiaodong (view profile)

Good stuff! Thanks.


Nils (view profile)

This is amazing. So easy to visualize complex regions! I love it.


Wu (view profile)


This is amazing! It was very useful for my purpose (I am developing a GUI to show the steps that simplex takes to solve an optimization problem). But I have a question: is it possible to draw different faces of the polyhedron with different colors? I like to have some nice and colorful figure for the feasible region of the problem which is a polyhedron.


Matt J

Matt J (view profile)

I like it a lot. As a minor point, though, it would be good if you could return a plot handle as an output argument.


Y (view profile)

Very good file. I love it. Thanks for sharing


Magnus (view profile)

Thanks for a nice package - it saved me quite some time! A hint to users: You get the error "Vector must have 4, 6, or 8 elements." if you specify an unfeasible set, i.e. if your A and b are such that no x fulfill Ax >= b. In my case, it was because I happened to define the normal vectors so they point out instead of in, i.e., the sign of A was reversed.

Rodrigo Lopez

very good! just what i need for my thesis. Thanks!

Juan Carlos: You can close your polyhedron by adding goods upper and lower bounds.

Thierry Dalon

Good contribution!

Juan Carlos Trillo

I was looking for something similar, great!
Only one question, how can one do to appropiately define the planes to plot general closed regions?

Jianing Di

I think it is very useful.

Steven Randolph



E. Hearn

I am sure this works well, but it needs clearer documentation. I simply cannot understand the format.
"The region(s) x is a subset of R2/R3 s.t. A*x>=b and lb<=x<=ub" is rather cryptic.

Golnaz Habibi

mc k

a a

Amir Ali Ahmadi

After hours of playing around with different m-files, trying to figure out how to fill the region b/w the intersection of some planes in R^3, I found this m-file which took care of the job in less than a minute.

Matlab has a built-in function ?area? for 2-D but nothing for 3-D (to my understanding).

I used plotregion.m to visualize a subset of R^3 where all the vectors have norm-1 less than say 3. (i.e. abs(x)+abs(y)+abs(z)<=3). This is easily done using this m-file by inputting an 8x3 constraint matrix A.

Thanks a lot & great work?


Peter Larsen

Just what I needed. Thanks.

John D'Errico

Splendid. A very nice utility that I'll happily use. I'd have
liked more documentation in the help, but I tend to go
overboard there myself, so my standards may be deemed
excessive by sane, rational beings. The examples were
enough to figure it out.



More examples are added.

John D'Errico had an idea how to do the program more user-friendly. That was by adding simpe bounds, lb & ub, to the arguments. So I did.

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