Editing Bounding volume (section)

==Uses==
Bounding volumes are most often used to accelerate certain kinds of tests.

In [[Ray tracing (graphics)|ray tracing]], bounding volumes are used in [[ray-intersection test]]s, and in many [[rendering algorithm]]s, they are used for [[viewing frustum]] tests.  If the ray or viewing frustum does not intersect the bounding volume, it cannot intersect the object contained within, allowing [[trivial rejection]]. Similarly if the frustum contains the entirety of the bounding volume, the contents may be [[trivially accepted]] without further tests. These intersection tests produce a list of objects that must be 'displayed' (rendered; [[rasterization|rasterized]]).

In [[collision detection]], when two bounding volumes do not intersect, the contained objects cannot collide.

Testing against a bounding volume is typically much faster than testing against the object itself, because of the bounding volume's simpler geometry. This is because an 'object' is typically composed of polygons or data structures that are reduced to polygonal approximations. In either case, it is computationally wasteful to test each polygon against the view volume if the object is not visible. (Onscreen objects must be 'clipped' to the screen, regardless of whether their surfaces are actually visible.)

To obtain bounding volumes of complex objects, a common way is to break the objects/scene down using a [[scene graph]] or more specifically a [[bounding volume hierarchy]], like e.g. [[Oriented bounding box|OBB tree]]s. The basic idea behind this is to organize a scene in a tree-like structure where the root comprises the whole scene and each leaf contains a smaller subpart.<ref>{{cite journal
 | last1 = Klosowski | first1 = James T.
 | last2 = Held | first2 = Martin
 | last3 = Mitchell | first3 = Joseph S. B. | author3-link = Joseph S. B. Mitchell
 | last4 = Sowizral | first4 = Henry
 | last5 = Zikan | first5 = Karel
 | doi = 10.1109/2945.675649
 | issue = 1
 | journal = IEEE Transactions on Visualization and Computer Graphics
 | pages = 21–36
 | title = Efficient Collision Detection Using Bounding Volume Hierarchies of k-DOPs
 | volume = 4
 | year = 1998}}</ref>

In [[computer stereo vision]], a bounding volume reconstructed from silhouettes of an object is known as a "[[visual hull]]."<ref>Erol, Ali, et al. "[https://www.researchgate.net/profile/Richard-Boyle-5/publication/220939129_Visual_Hull_Construction_Using_Adaptive_Sampling/links/0deec528d6c7ea8188000000/Visual-Hull-Construction-Using-Adaptive-Sampling.pdf Visual Hull Construction Using Adaptive Sampling]." WACV/MOTION. 2005.</ref>