Lighting geometric solids - coordinating 3d renderings with reality

The 3d renderings done in Maya prior to this were executed with a general knowledge of lighting from an industrial design education and practice perspective: establish a primary light source ("key light") in a position that illuminates important features of the object/product, casts shadows which help to define features and create a sense of visual depth, and provides secondary lighting to surfaces in shadows with reflected light.

Some assumptions can be made about secondary lighting: with the product resting on or near a ground plane, some light from the overhead primary source will reflect off that plane and up to surfaces in view; ambient light will help to illuminate surfaces in shade cast by the primary light; light from the far horizon is generally portrayed as indirect and cool in nature, illuminating receding surfaces and adding a cool hue to the color which, in turn, adds to visual depth. The earlier Roland Stickney rendering of a John Deere tractor illustrates these principles.

Translating these principles to a Maya image required a reasonable understanding of the software. The results were exhibited in the last posting:

Fig.01

Figure 01 shows geometric solids composed to take advantage of highlights and cast shadows to create a better sense of visual depth and object surface definition. The modeling, however, is still crude because the facets of the polygonal surfaces don't accurately portray real life. Revisions of these features helped to make the highlighted portion of the cone, for example, more realistic as shown in Figure 02 and 03. Addition of edge radii to the cube and cylinder integrated highlights enhancing the 3-dimensional aspects.



Fig.02 - before and after solids surface refinements

 

Fig.03 - refinements to rendered surfaces and definition

Figure 03 sets the stage for the next, essential step in the process of establishing benchmarks for the designer to understand and execute visualizations of illuminated products: photograph the same geometric solids in a studio setting to establish visual benchmarks to verify the logic and mechanics of a drawing system.



Figure 04 is an image of the geometric solids composition photographed in a studio setting with one primary/key light but no ambient, rim, fill or reflected secondary lights.

Fig. 04 - studio lighting composition

While the positioning of the objects and key light are close to the same as in the Maya composition the effects of the lighting are noticeably different. Regardless of the different color value of the computer versus real solids, the light reflected of the #2 surfaces (vertical surfaces facing the direction of the light) is significantly more. Light reflecting of the top plane of the cube into the underside of the sphere is significant. Ambient reflected light from the cone and cylinder into the left side of the sphere is less than indicated in Maya. The highlighted surface of the cone reflects considerable light into the left, shaded surface of the cylinder. Cast shadows vary widely depending on objects and respective illuminated or shaded surfaces in the background.

Refining the Maya light configurations will be the next step to more accurately represent the connection between studio lighting and the computer model.