# Help with Matlab plots

1. Aug 15, 2007

### jenga42

Hi,

I'm trying to plot a 3d graph of when a function, F(i,j,k) = 1 ...I want to plot 3 variables that correspond to the i j and k against each other when the function equals 1.

...I've tried using surf but it tells me that its Z component needs to be a matrix, not a scalar or vector.. but I don't know how else to do it.

Any help would be greatly appreciated!

Thanks!

2. Aug 15, 2007

### las3rjock

It sounds like you're trying to display the $$F(i,j,k) = 1$$ isosurface. The correct MATLAB function to use would be isosurface, so you may want to look up that function in MATLAB's help system to see how to use it correctly for your problem.

3. Aug 15, 2007

### jenga42

Hi,

Thanks for your reply. Unfortunately, I don't think the isosurface function will work in my case as although I want to plot when F(i,j,k)=1, the function never precisely equals 1: I'll need to plot something like 0.99<F(i,j,k)<1.01.

Any other suggestions would be greatly appreciated!

Thanks

4. Aug 15, 2007

### jenga42

Actually I tried it just incase, and it works! ...Though I'm not really sure why! - Does isosurface estimate the values corresponding to i, j and k where F(i,j,k)=1?

- Thank you!!!