Hi,

an AABB can be defined using two methods.

The first method is to define an AABB as a min and a max.

Using this methode, extents is the vector 0.5f * ( max - min ), center is 0.5 * ( min + max ).

The second method is to define directly an AAAB as a center and extents.

Both method works but what method do you prefer and why ?

I seen a lot of people who use the min/max method.

XNA use the second (center+extents) and says :

Whichever method best fits the problem in hand. If you are always querying min/max points, use that method. If you always query center + extents, use that instead. Converting from one to the other is super cheap, so there isn't really a problem either way (it's never going to cause a significant performance hotspot)