Culling

In biology, culling is the process of segregating organisms from a group according to desired or undesired characteristics. In animal breeding, culling is the process of removing or segregating animals from a breeding stock based on specific criteria. This is done either to reinforce or exaggerate desirable characteristics, or to remove undesirable characteristics from the group. For livestock and wildlife, culling often refers to the act of killing removed animals. In fruits and vegetables, culling is the sorting or segregation of fresh harvested produce into marketable lots, with the non-marketable lots being discarded or diverted into food processing or non-food processing activities. This usually happens at collection centres located at, or close to farms. Culling is sometimes used as a term to describe indiscriminate killing within one particular species which can be due to a range of reasons, for example, badger culling in the United Kingdom.

Origin of the term

The word comes from the Latin colligere, which means "to collect". The term can be applied broadly to mean sorting a collection into two groups: one that will be kept and one that will be rejected. The cull is the set of items rejected during the selection process. The culling process is repeated until the selected group is of proper size and consistency desired.

Hidden surface determination

In 3D computer graphics, hidden surface determination (also known as hidden surface removal (HSR), occlusion culling (OC) or visible surface determination (VSD)) is the process used to determine which surfaces and parts of surfaces are not visible from a certain viewpoint. A hidden surface determination algorithm is a solution to the visibility problem, which was one of the first major problems in the field of 3D computer graphics. The process of hidden surface determination is sometimes called hiding, and such an algorithm is sometimes called a hider. The analogue for line rendering is hidden line removal. Hidden surface determination is necessary to render an image correctly, so that one cannot look through walls in virtual reality.

Background

Hidden surface determination is a process by which surfaces which should not be visible to the user (for example, because they lie behind opaque objects such as walls) are prevented from being rendered. Despite advances in hardware capability there is still a need for advanced rendering algorithms. The responsibility of a rendering engine is to allow for large world spaces and as the world’s size approaches infinity the engine should not slow down but remain at constant speed. Optimising this process relies on being able to ensure the deployment of as few resources as possible towards the rendering of surfaces that will not end up being rendered to the user.

Culling (disambiguation)

Culling may refer to: