of the present inventions shadows and lighting can be altered in real time and photographic images appear as an interactive photographic image application_number US 93948607 A description the following detailed description is directed to certain specific embodiments of the invention however the invention can be embodied in a multitude of different ways as defined and covered by the claims the term u201c real time u201d as used herein when referring to image manipulation of the interactive photographic scene means that the image changes under user control in a single display window and appears photographic for a majority of the time a user would view the virtual object when evaluating the design of a cad defined virtual object the term u201c photographic u201d as used herein means the image being manipulated appears in the manipulation window in a manner that is substantially indistinguishable from a digital image obtained with conventional photographic techniques of an actual physical object as objects are modeled in 3d modeling or computer aided design systems the rendering of the objects in response to user actions may be viewed in terms of a trade off between responsiveness and quality one embodiment includes a real time ray tracing system configured to compute refractions glossy reflections shadows and indirect illumination such as caustics and color bleeding in computer graphics and 3d rendering color bleeding is the phenomenon in which objects or surfaces are colored by reflection of colored light from nearby surfaces the.