Main problem in visualization:

The main problem in visualization is the display of three-dimensional objects and scenes on two-dimensional screens. How can the third dimension, the depth, be displayed on the screen? How can the visual complexities of the real environment such as lighting, colour, shadows, and texture be represented as image attributes? What complicates the display of three-dimensional objects even further is the centralized nature of the databases of their geometric models. If we project a complex three-dimensional model onto a screen, we get a complex maze of lines and curves. To interpret this maze, curves and surfaces that cannot be seen from the given viewpoint should be removed. Hidden line and surface removal eliminates the ambiguities of the displays of three-dimensional models and is considered the first step toward visual realism.