> I would not be surprised to find mistakes or inconsistencies here and > there as I think Vaclav developped the framework but did not really use > it for now. Right, I never used it. > If nothing changed since last time we discussed that in Grenoble, you > could also find the definition of clumps inertia a bit weird : it is the > inertia of a sphere of equivalent mass (I suggested that for > quasi-static problems it would be an acceptable approximation, and it > was easier to code, so...). > Consequence of that : clumpRBP->inertia is an isotropic matrix, > independant on the coordinate system, and equations above are correct. :) Clump::updateProperties computes full intertia matrix and changes clump orientation so that its local axes are principal (eigenvalue problem). Unless spheres overlap, the inertia matrix should be "exact". I cannot guarantee that it is correct though. I never verified results against a by-hand calculation. > If somebody takes time to compute the correct inertia matrix, then > inertia will have to be rotated, I agree. Don't we have th same problem with regular bodies as well? Inertia matrix (body-local coords) is used unrotated in NewtonsDampedLaw to compute angularAcceleration (global coords)? Sega pointed taht out earlier already IIRC.
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