In 3D computer graphics, popping refers to an undesirable visual effect that occurs when the transition of a 3D object to a different pre-calculated level of detail (LOD) is abrupt and obvious to the viewer. The LOD-ing algorithm reduces the geometrical complexity of a 3D object the further it is from the viewer and returns that lost complexity as the viewer gets closer to the 3D object, causing it to pop as it becomes suddenly more detailed. The LOD-ing algorithms can depend on more factors than just distance from the viewer, but it is often the primary factor that is considered. Popping is most obvious when switching between different LODs directly without intermediate steps. Techniques like geomorphing and LOD blending can reduce visual popping significantly by making the transitions more gradual.