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## Plot 2D/3D region

version 1.1.0.0 (10.9 KB) by Per Bergström

### Per Bergström (view profile)

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

Updated 04 Jan 2010

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)

### Cite As

Per Bergström (2020). Plot 2D/3D region (https://www.mathworks.com/matlabcentral/fileexchange/9261-plot-2d-3d-region), MATLAB Central File Exchange. Retrieved .

sepanta sln

Deepak Prakash K

### Deepak Prakash K (view profile)

Thanks for this. Is it not possible to place a point somewhere in the region? I am able to place points only at the extreme points of the region.

Jenny O'Jhene

### Jenny O'Jhene (view profile)

Thanks for this. it solves my problem perfectly!!

majid

### majid (view profile)

I wanted to draw simplex (2D and 3D), and it was bugy! the shape was completely wrong.

Shane Loser

### Shane Loser (view profile)

Amazing! So useful! Only minor point: Why set up up the region such that Ax>=b, when the standard MATLAB form for linear programming is Ax<=b

Ganesh

Sarah Sachs

### Sarah Sachs (view profile)

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;

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

where f, g, and k are nonlinear functions.

Thanks,
Sirvan

Andy Andy

lufei

very good

Hristo

### Hristo (view profile)

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

Nan

### Nan (view profile)

Is there anybody could tell me what the meaning of
b?Thx

Naftali

### Naftali (view profile)

ax<=b is euivalent to -ax>=-b

Song

### 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?

Xiaodong

### Xiaodong (view profile)

Good stuff! Thanks.

Nils

### Nils (view profile)

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

Wu

Mahshid

### Mahshid (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.

Thanks.

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

### Y (view profile)

Very good file. I love it. Thanks for sharing

Magnus

### 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

PA L

interesting

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

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?

-AAA

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.