isosurface (MATLAB Function Reference)

Extract isosurface data from volume data

Syntax

fv = isosurface(X,Y,Z,V,isovalue)
fv = isosurface(V,isovalue)
fv = isosurface(X,Y,Z,V), fv = isosurface(X,Y,Z,V)
fv = isosurface(...,'noshare')
fv = isosurface(...,'verbose')
[f,v] = isosurface(...)
isosurface(...)

Description

fv = isosurface(X,Y,Z,V,isovalue) computes isosurface data from the volume data V at the isosurface value specified in isovalue. The arrays X, Y, and Z define the coordinates for the volume V. The struct fv contains the faces and vertices of the isosurface, which you can pass directly to the patch command.

fv = isosurface(V,isovalue) assumes the arrays X, Y, and Z are defined as [X,Y,Z] = meshgrid(1:n,1:m,1:p) where [m,n,p] = size(V).

fv = isosurface(...,'noshare') does not create shared vertices. This is faster, but produces a larger set of vertices.

fv = isosurface(...,'verbose') prints progress messages to the command window as the computation progresses.

[f,v] = isosurface(...) returns the faces and vertices in two arrays instead of a struct.

isosurface(...) with no output arguments creates a patch using the computed faces and vertices.

Remarks

You can pass the fv structure created by isosurface directly to the patch command, but you cannot pass the individual faces and vertices arrays (f, v) to patch without specifying property names. For example,

patch(isosurface(X,Y,Z,V,isovalue))

[f,v] = isosurface(X,Y,Z,V,isovalue);
patch('Faces',f,'Vertices',v)

Examples

This example uses the flow data set, which represents the speed profile of a submerged jet within an infinite tank (type help flow for more information). The isosurface is drawn at the data value of -3. The statements that follow the patch command prepare the isosurface for lighting by:

Recalculating the isosurface normals based on the volume data (isonormals)
Setting the face and edge color (set, FaceColor, EdgeColor)
Specifying the view (daspect, view)

Adding lights (camlight, lighting)

[x,y,z,v] = flow;
p = patch(isosurface(x,y,z,v,-3));
isonormals(x,y,z,v,p)
set(p,'FaceColor','red','EdgeColor','none');
daspect([1 1 1])
view(3)
camlight 
lighting phong