How to convert a binary 3d matrix to mesh.

I have a 3D binary matrix with 1 being filled volume, and 0 being empty. For example I've added a representation of this matrix filled with a sphere but the matrix could also have been filled with irregular content.

I would like to construct a mesh from 3D binary matrix volume, how would I go about it?

I have come across the isosurf function, but I was not sure if it was applicable or how to get my data in the right format.

Thanks.

Answer 1

[Mike Garrity]

Yes, I would think that isosurface is the first thing to try. Just give it the 3D array and an isolevel of 1/2. It'll use linear interpolation to put a surface down the middle of where the 1's and 0's meet.

[x,y,z] = ndgrid(-1:.05:1);
v = sqrt(x.^2+y.^2+z.^2) < .5;
isosurface(v,1/2)

As you can see, the result can be a little lumpy.

If you want your mesh to follow the grid without any interpolation, then you'll probably want a different approach.

[MG Poirot]

Thanks! This'll work great for visualizing and exporting my MRI data!

[Karima benzaid]

Hi,

I have a 3D binary grid of a canyon (obstacle=1, free-space=0). I would like to get something like this (with filled volume)

But, what I get when using isosurface(Map) is this

Am I missing something?

Thanks.

[Xander May]

Karima, it would seem your 3D object does not have a 'Surface' anywhere besides what you are seeing. The ISOSURFACE function creates a mesh of the surface of an object, but because your object only has a surface where the interior walls of the canyon are, with other thigns extending out of the view window, that is the only part ISOSURFACE is able to render

Answer 2

[Noor Aamer]

How can I get a 3D binary image from 2D binary image?

[Md Nurul Karim]

Just stack the 2D binary images on top of each other and make a 3D binary matrix.

then you can watch it in Volume viewer app.

You can also extract surface out of it.