Hi Mariusz,
In your code you assume Ix=1, Iy=5, Iz=15
Assuming the shape as in your file, assuming density constant =1, we have
Ix = Int(y^2+z^2) = y2+z2
Iy = Int(x^2+z^2)=x2+z2
Iz = Int (x^2+y^2)=x2+y2
Where the integration is over the body, and I denoted x2,y2,z2 the corresponding integrals. From your conditions we should have
x2+z2=5(y2+z2)
x2+y2=15(y2+z2)
Eliminating x2 we get 9y2+11z2=0, which is clearly impossible since y2>0,z2>0. Can you make a realistic model?