____ | 1 | |____| | 2 | |____|

I start with a search direction of ( 0, 1 ) which finds the support points:

Box 1 - ( 5, 15 )

Box 2 - ( 5, -5 )

This yields the GJK support point of ( 5, 15 ) - ( 5, -5 ) == ( 0, 20 ). The Y term is correct but the X term is obviously wrong; the correct point on the Minkowski difference is ( 20, 20 ). This is found if Box 2's vertex at ( -5, -5 ) is used, but because both ( 5, -5 ) and ( -5, -5 ) meet the max( -DtBj ) requirement it depends which vertex was added to the hull first.

Question is how to guarantee the correct vertex is found to calculate the difference? Bonus points for a solution which works in 3 dimensions as that is the world the algorithm lives in.

**Edited by chandlerp, 04 November 2012 - 03:45 PM.**