Rendering View by View
View By View calls their image processing technique "synthetic rendering." Boryslawski describes this as "3D digital objects or scenes with their assigned physical-based material properties, lighting conditions, and a camera with a chosen field of view."
The 3D digital model contains geometric data and other information such as the material properties of each object and the lighting within the scene. To render a "photorealistic" image, the designer must also specify the object's attributes of color, texture, transparency, edge density, reflections, and lighting.
Boryslawski and Israel use this technique in a variety of projects including games and architectural proposals and reproductions. A stunning example of their work is the CD-ROM-based Myst-style educational game "Qin: Tomb of the Middle Kingdom" published by Time Warner.
The Emperor's Tomb
In 1974, Chinese archaeologists uncovered life-sized terracotta statues near the second century B.C. tomb of the Emperor Qin Shihuangdi. Among other objects, they have excavated an "army" of about 6000 soldiers and horses created to guard the tomb. In the game, the players take the role of archaeologists discovering the still-unexcavated underground tomb and palace.
Boryslawski and Israel modeled the tomb for the Qin game based on investigations done in China and at Harvard University, and on their own intuition, imagination, and knowledge of neighboring architecture of the period.
For the Qin game experience, Israel created over 1200 renderings, providing four to ten views for each room. She used a Macintosh Quadra 900 with 256 MB of RAM, form-Z, Electric Image, and Photoshop to create the renderings. She scanned material textures with a Hewlett Packard scanner.
The 3D modeling was done with form-Z, and the model files were saved in the Electric Image FACT format. Israel then opened these files into Electric Image for rendering.
In Electric Image, Israel added lights, textures, and camera views to the geometry from form-Z. She adjusted lighting precisely in the Electric Image rendering environment, so a minimum of retouching was needed downstream in Photoshop.
Working with Textures
Images of the emperor's chamber with and without textures demonstrate the visual potency that materials have in rendering an evocative and convincing image.
The textures for the Qin images were created with Photoshop directly from scanned photographs of artifacts and buildings of the same time period as the tomb. The scanned images were carefully cropped and adjusted so the texture patterns tile smoothly, without appearing repetitive, or tiled, when mapped to objects.
Israel saved each texture image file with an Electric Image plug-in for Photoshop so it would be available to use in the rendering program. In Electric Image, texture mapping tools are used to apply the pixel images to object surfaces, so the objects look like the texture was painted on.
Within Electric Image, Israel also adjusted other material properties such as reflectivity and opacity. She notes that it is important to assign the appropriate material attributes, such as whether an object is shiny, dull, matte, metallic, or glowing for each object in a scene.
For instance, to create softness in the bed curtains in the emperor's chamber and to add realism to the image, she assigned patterns of transparency as well as texture to the curtain object. Transparency maps were also assigned to the curtains of the puppet stage in the dining chamber to reveal holes in the material.
In the dining chamber, the distinction between the metallic shininess of the candlestick and the duller metal of the artifacts on the table is enhanced by a "roughness" pattern applied as a "bump map."
Setting the Lighting
While texture mapping is important in conveying a realistic image, Israel finds that by far the most challenging aspect of any digital rendering is lighting.
For the Qin project, lights were placed to achieve an effect and set a tone, rather than to portray light accurately. In addition to ambient light, three "special effect" light types used in Electric Image were spot, parallel, and radial lights. Most of the lights were given a nonwhite color as well, typically in the red/orange range.
The Electric Image spotlight was used to focus on objects and to create shadows. This light type is defined with inner and outer cones of rays. The greater the distance between the inner and outer cones the softer the light. A radius value determines the spread of light, from a flood to a tight spot.
The parallel light type creates an effect analogous to sunlight, with all rays going in the same direction, evenly dispersed. With the radial light type, the rays emanate as if from the entire surface of a light ball. The radial light may be used to augment ambient light and create atmospheric effects.
In Electric Image, the light sources themselves have no visual representation, so they are invisible. For a physical source of light, such as a candle flame or light bulb, to appear in a scene, an object representing the physical source must be created. Otherwise, light may appear as if it emanates mysteriously from a unseen source. Images in the Qin project use both approaches.
In the music chamber, an unseen spotlight placed on the floor is focused on the bird-shaped instrument in the corner. This creates dramatic shadows on the wall behind the instrument and draws the viewer's attention to the bird figures as the focal point of the scene.
Israel used the radial light with the "fog" attribute to create an impression of dustiness. Some rendering programs include the capability to automatically track the drop-off of light intensity over distance from the source. Working in Electric Image, Israel makes these adjustments by trial and error.
When Israel uses the radial light and specifies a drop-off point at which the light starts to fade, she achieves a light effect that is more dense at its source and diffuse in the distance. The depth of the drop-off determines how "foggy" the light seems.
In the tomb chamber, unseen radial and spotlights work in tandem. The air is filled with dust. Sunlight streams through an unseen opening above and brings into focus the figure of the Emperor Qin enshrined in his unexcavated tomb.
Israel sets up these "special effects" lights first with a little ambient light to give an overall illumination to the space. She then compensates for any deficiencies with additional radial lights until the desired effect is achieved.
The series of images for the dining chamber show how important the selection and placement of artificial special-effects lights are in setting the tone.
In the Qin images, Israel notes, "textures and lighting vie for first place in terms of importance." Subdued lighting creates an atmosphere of antiquity and the look of "dust in the air" appropriate for an underground palace and tomb.
Boryslawski concludes: "we all have limits as to the time we can spend on a project in order to compete in this fast-growing marketplace and remain in business. Clients have budgets and once they realize the economic benefits of having high-quality projects produced in digital media, they will be willing to increase their spending."
He believes it will not be long before "this form of visualization becomes the standard practice within the design profession."
Mieczyslaw Boryslawski and France Israel are principals in View by View.
Darlene A. Brady is a registered architect and contributing editor to ArchitectureWeek. She is author of the forthcoming book Architectonic Color: Its Virtual And Physical Reality.