3D Polygons can be displayed simply by displaying exactly the color that was assigned to them. However, rendering them as if they were illuminated by a light enhances their sense of depth and extent. Such lighting calculations are based on the surface's normal vector (perpendicular to the polygon) and the incoming light direction.

Normal vectors are usually calculated in a consistent fashion such that each polygon has a "front" side (in the direction of the normal vector) and a "back" side (in the opposite direction). Many graphics libraries and applications built upon them offer the option to not light or render the polygons that face away from the camera (often called "back-facing"), which cuts the rendering work in half. If there is no reason for you to see the "back" side of an object, select this option to speed display.

Many visualization applications offer shading options, which control way the polygons are illuminated by lights in the scene. Ambient lighting lights all surfaces equally and involves almost no computation. Diffuse lighting uses the angle between the normal vector and the direction to the light to produce relatively even shading at low cost. Specular lighting additionally takes into account the angle from the camera to the surface and can produce highlights and even reflections, but at significantly higher computational cost. Consider the amount of realism you need in your images or animations when selecting a shading model for your visualization.

Some visualization software will offer additional effects for additional (and sometimes very large) computation cost. Ray tracing is a technique the follows paths from the camera through the pixels of the image to find the visible surface, then follows more paths towards the light sources or to produce reflections and refractions off of the surface. It can add shadows and mirror- or glass-like materials to your images, but must be used carefully keep computation costs reasonable.

If your visualization does not look as it should, it may be due to incorrectly lighting or shader specifications. A black screen may be the result of having no light sources or sources that point in the wrong direction or do not emit any light. A washed out object can indicate that the sum of the contributions from your light sources is too bright. Visualization software sums the contributions from all available light sources, so they can produce a white appearance on non-white surfaces when some of the RGB channels are driven too high and clipped.