Visible Surface Detection - Modeling and Rendering

Provided a set of 3-Dimentional objects and a viewing position for the generation of realistic graphics show, we want to determine that lines or surfaces of the objects are visible, either from the center of projection, for perspective projections or along the direction of projection, for parallel projections, hence we can display merely the visible lines or surfaces. For such, we require to conduct visibility tests. Visibility tests are conducted to find out the surface which is visible from a specified viewpoint. This procedure is termed as visible-line or visible-surface determination or hidden-line or hidden-surface subscription.