3-D Visualization

Selecting a Lighting Method

When you add lights to an axes, MATLAB determines the effects these lights have on the patch and surface objects that are displayed in that axes. There are different methods used to calculate the face and edge coloring of lit objects, and the one you select depends on the results you want to obtain.

Face and Edge Lighting Methods

MATLAB supports three different algorithms for lighting calculations, selected by setting the FaceLighting and EdgeLighting properties of each patch and surface object in the scene. Each algorithm produces somewhat different results:

• Flat lighting -- Produces uniform color across each of the faces of the object. Select this method to view faceted objects.
• Gouraud lighting -- Calculates the colors at the vertices and then interpolates colors across the faces. Select this method to view curved surfaces.
• Phong lighting -- Interpolates the vertex normals across each face and calculates the reflectance at each pixel. Select this choice to view curved surfaces. Phong lighting generally produces better results than Gouraud lighting, but takes longer to render.

This illustration shows how a red sphere looks using each of the lighting methods with one white light source.

The lighting command (as opposed to the light function) provides a convenient way to set the lighting method.

Properties That Affect Lighting

Reflectance Characteristics of Graphics Objects

© 1994-2005 The MathWorks, Inc.