how can calculate irragular shape volume

Hi! I want to calculate volume srfShape. I tried cunvhull and alphashape and voxel but i coudn't make this. Can you help me?

Answer 1

[Star Strider]

Experiment with this approach:

F1 = openfig('surfShape.fig');
Surfc = F1.Children.Children;
X = Surfc.XData;
Y = Surfc.YData;
Z = Surfc.ZData;
ElementProduct = prod(cat(3,X,Y,Z),3);                                  % Products Of Corresponding Elements Of Matrices
ApproxVol = trapz(trapz(ElementProduct)) / (numel(X)*3);                % Integrate Result

Using an indirect check on the results (a cube with the limits of the elements):

[XL,XH] = bounds(X,'all');                                              % Check Results
[YL,YH] = bounds(Y,'all');                                              % Check Results
[ZL,ZH] = bounds(Z,'all');                                              % Check Results
Check = prod(diff([XL XH; YL YH; ZL ZH],[],2))                          % Check Results

produces:

ApproxVol =
     9.395695811724738e+03

and:

Check =
     9.635124211073383e+04

I do not understand the reason that the calculated volume and the upper limit of the possible volume are off by a factor of 10, other than that the ‘Check’ is obviously going to be larger since it uses the limits of the element values. I expected the difference to be less. This approach is somewhat empirical, since I have not encountered this sort of problem previously.