How to create volume out of surfaces?

I got these two surfaces from isosurface plot, thus I have all the coordinates of these surfaces. I would like to fill in between the two surface to create a 3d solid part. How can I do that?

Answer 1

[darova]

Your object looks symmetrical. Try manually to create surface

p1 = isosurface(...);
p2 = isosurface(...);
v1 = p1.vertices;
v2 = p2.vertices;
ix1 = v1(:,3) > (max(v1(:,3))-0.05);      % find z coord of boundary
ix2 = v2(:,3) > (max(v2(:,3))-0.05);      % find z coord of boundary
[t1,r1] = cart2pol(v1(:,1),v1(:,2));      % extract data first contour
[t2,r2] = cart2pol(v2(:,1),v2(:,2));      % extract data second contour
ind1 = sort(t1);                          % order points counter clockwise
ind2 = sort(t2);                          % order points counter clockwise
    % data can be of different size. Interpolate data to make the same size
r22 = interp1(t2,r2,t1);                  % make two contours same size as second one
x1 = v1(:,1);
y1 = v1(:,2);
z1 = v1(:,3);
[x2,y2] = pol2cart(t1,r22);               % second contour
z2 = z1;
    % create data for surface
X = [x1(:) x2(:)];
Y = [y1(:) y2(:)];
Z = [z1(:) z2(:)];
surf(X,Y,Z)

[Teerapong Poltue]

well, I've tried this code but it turns out pretty weird. Since I would like to export this as an .stl file as a solid for futher CAD. Similar to surf2solid, but solid between the 2 surfaces.

[darova]

Please upload the data for experiments

[Teerapong Poltue]

here

[darova]

What about this?

s = load('data.mat');

p1 = s.co{1};
p2 = s.co{2};

v1 = p1.vertices;
v2 = p2.vertices;
ix1 = v1(:,3) > (max(v1(:,3))-0.1);      % find z coord of boundary
ix2 = v2(:,3) > (max(v2(:,3))-0.1);      % find z coord of boundary
v11 = v1(ix1,:);
v22 = v2(ix2,:);
[t1,r1] = cart2pol(v11(:,1),v11(:,2));    % extract data first contour
[t2,r2] = cart2pol(v22(:,1),v22(:,2));    % extract data second contour
    % order points counter clockwise
[t1s,ind1] = sort(t1);                     
[t2s,ind2] = sort(t2);                     
r1s = r1(ind1);
r2s = r2(ind2);
    % there are repeated values. Select unique only
[t1u,i1] = unique(t1s);
[t2u,i2] = unique(t2s);
r1u = r1s(i1);
r2u = r2s(i2);
    % make closed contour
t1u(end+1) = t1u(1)+2*pi;
t2u(end+1) = t2u(1)+2*pi;
r1u(end+1) = r1u(1);
r2u(end+1) = r2u(1);
    % Interpolate data to make the same size
t11 = linspace(min(t1u),max(t1u),30);
t22 = linspace(min(t2u),max(t2u),30);
r11 = interp1(t1u,r1u,t11);
r22 = interp1(t2u,r2u,t22);
    % get cartesian coordinates
[x1,y1] = pol2cart(t11,r11);
[x2,y2] = pol2cart(t11,r22);
z1 = max(v1(:,3)) + x1*0;
z2 = z1;
    % create data for surface
X = [x1(:) x2(:)];
Y = [y1(:) y2(:)];
Z = [z1(:) z2(:)];
surface(X,Y,Z)
patch(p1,'facecolor','red')
patch(p2,'facecolor','green')
view(45,45)

[Teerapong Poltue]

Well the space between two surfaces still being a void space, I would like to fill that with solid.

[darova]

Maybe look into alphaShape

Answer 2

[DGM]

Here are two examples of using isosurface() and isocaps() to assemble a closed triangulated surface describing a solid.

https://www.mathworks.com/matlabcentral/answers/1732640-how-to-export-a-3d-surface-gyroid-into-an-stl-file

https://www.mathworks.com/matlabcentral/answers/581193-cylindrical-ring-of-implicit-surfaces

If the expectation is that the representation is somehow supposed to be a solid, then one needs to ask what's meant by "fill with solid", and why that's necessary. The given examples are sufficient to establish a solid model for the PDE toolbox tools. At that point, you can mesh it however you want. If all you need to do is feed it to CAD/CAM software, then all you need is a closed surface.