Hello, I would like find a way to figure out how many unique collision there are between 2 equally subdivided ellipsoids (velocity=1). When you have 2 ellipsoids and you let them collide than you have an infinite amount of possible outcomes. The goal is to reduce this infinite number to a manageable list of for example unique 32 collisions by: Subdividing the ellipsoids, so instead of having an infinite number of points on these ellipsoids where they can hit, they are subdivided into 3 zones (I-II-III per quarter). Reduce the possible rotation angles into steps of 15° Using symmetry, to cancel out the collisions that are the same when A hits B vs. B hits A, and the outcome of a collision on the left side is symmetric to one on the right, or back and front etc. (Note, the use of 3 Zones and 15° Angles is arbitrary, i guess once a method is found these could be easily changed into whatever.) -- Attached is an overview where the Ellipse A is Set and B comes flying in (see pic.), and where: B is shifted a couple of steps along the vertical-axis (right-top). B is rotated in relation to A in steps of 15° (left-bottom) B is rotated in relation to A in steps of 15° and B itself is rotated 15° (right-bottom) B is shifted a couple of steps along the horizontal-axis and B itself is rotated 105°(left-top). -- I don't know if such a method already exists or if this is perhaps something that should be solved with a Monte Carlo method or ... all suggestions are welcome to tackle this issue. Kind regards, m.