hi.. i am working on making a rigid body simulation and i have to compute the body inertia tensor matrix.. in David Baraff tutorials, i found a very nice equation to compute it from a bousing box.. my broblem is.. am trying to simulate a robot composed with a set of bounding boxes (which might be oriented) i should compute the inertia tensor matrix in body space before starting the compuation(or at any moment something moves in the robot) i tried to compute the matrix assuing that the masses are distributed in each box on its 8 corners and summ all points... ...even for a single box.. the computation didnt give the same resluts as the simple box matrix... well... i am trying to find the best way to compute the inertia matrix (in body space)..given the set of points desrirbing the body and their masses... i think i could approxiamte all the points into a single bouding box...but i dont know how exactly to compute that bounding box can any help?

I''ve probably misunderstood the question, but rigid-body means
that each body is rigid (!) Thus you can calculate the mom. of inertia ounce for all at design-time of that body. However if you somehow put bodies together (uhm, with nails?) then you have to recalculate at that instant.

Simulating a robot arm must be a lot of work - I mean just to calculate the forces in each joint is ... to much for me

/Ola