AABB border, Obb border, surround by comparison ball

1) AABB bounding box: AABB bounding box is aligned with the axis of the bounding box, the simplicity of good, poor tightness (especially in the diagonal direction of the elongated shape of the object, the use of AABB, will leave a very large corner gap, resulting in a large number of not required bounding box intersection test). When the object rotates, the AABB should be rotated and updated. Once the object is deformed, it is only necessary to calculate the bounding box of the deformed basic geometrical elements again. It is then possible to synthesize the AABB of the parent node from the aabb of the child node, and finally to update the bounding box tree.

2) OBB bounding box: OBB Collision Detection method tightness is good, can greatly reduce the number of the bounding box of the intersection test, so the overall performance is better than AABB and surround the ball, and the degree of real-time is higher. When the object rotates, it is only necessary to obb the same rotation. Therefore, OBB is a better choice for collision detection between rigid bodies. So far, there is not an effective method to solve the problem of Obb tree after the deformation of object, but it is too expensive to compute the OBB of each node once more.

Therefore, OBB does not apply to complex environments that include software objects.

Extended References:

Http://hi.baidu.com/jorbin/blog/item/2e7c2df5c146f423bd310977.html/cmtid/c13785356aaa081f90ef39bf

Http://www.cnblogs.com/gamesoul/archive/2007/05/29/764523.html

3) surround the ball: the bounding ball collision detection method is to surround the entire geometry with the sphere, whether it is the geometry or the intersection test is very easy; But its tightness is too poor. In addition to the more evenly distributed geometry on 3 axes, almost all of them leave large voids, requiring a lot of preprocessing time to construct a good hierarchical approximation of the object. When the object is deformed, the surrounding ball tree needs to be calculated again.

Therefore, it is used less than a bounding box. When the object rotates, the bounding ball does not need to be updated, which is the better display performance of the bounding ball; When a geometric object rotates frequently, the surrounding ball can be used to get better results.

Side Mei Ling, Jingianping. Research in the surrounding area of collision detection techniques.  Mechanical management development. 2008

AABB border, Obb border, surround by comparison ball