Being scratching my head for 2 days and not getting anywhere with this one. I am trying to figure out how to perform a 3D rotation described via a mix of intrinsic and extrinsic angles. Here is the problem: I have a platform in the shape of a box with sides of length lx, ly and lz. The platform has an inclinometre measuring angles α and β from the vertical about lx and ly and a fluxgate compass measuring heading. I have a global Cartesian measurement p(x,y,z) of the top-right-front corner of the box and I would like to calculate the location of the centre of the box given p, α, β, γ, lx, ly and lz I would know the solution if: - α, β and γ were purely intrinsic rotations, or - α, β and γ were purely extrinsic rotations Due to compass reading being global, but the inclinometre readings being local, I am not sure what to do. Does anyone have any pointers?