Keeping rendering in mind when you model a scene can help you reduce rendering time. For more information about modeling, see Modeling and Deformation Basics.

• Try to reduce the number of objects in each scene. Using fewer objects keeps the rendering time down.

• Try to use the lowest number of polygons possible on polygon meshes.

• Try to reduce the complexity of NURBS objects. Often, you can use surface approximation to make them look smooth at render time.

• Use subdivision surfaces (subdees) to simplify the model and the texturing process.

• The more geometric detail an object has, the longer it takes to render. Try to substitute some of an object's geometric detail with a texture map. From a distance, the difference may not be distinguishable.

• You can simplify the calculations required for shadows, reflections, and refractions by adding invisible objects to the scene.

  Suppose you have an object that is generally spherical but has a great deal of surface detail. Set its object properties so that it is visible to primary rays and secondary rays but does not cast a shadow. In the same position, add a second, simpler object that casts a shadow, but is otherwise invisible.

  The end result is an image that appears correct but for which the shadow computations are much less expensive. A similar technique can be employed so that secondary (reflected and refracted) rays see a much simpler object.