Research: Design
Color Visualization

We are developing new techniques to simulate and visualize the color and appearance of architectural surface finishes. The materials that are under investigation include traditional exterior and interior coverings such as paint, tile, and marble. In addition we are exploring computer graphic methods that allow us to model light reflection from emerging architectural coatings such as anodized metal surfaces and physics based paints. Our research makes extensive use of the shader hardware that has recently become available on PC graphics cards. We are particularly interested in exploiting the interactivity provided by shaders to develop tools that will allow manufacturers and color scientists to design new types of architectural coatings. In addition, we are looking at unique ways to display the results of surface appearance simulations that overcome some of the limitations inherent in existing CRT and LCD displays.

Metallic surface finishes used for the Experience Music Project (EMP)

New Reflection Models — New paints are now being manufactured that use interference and diffraction, in addition to simple absorption, to change the color of the light reflected from a surface. These physics based coatings can produce unusual effects, such as dramatic changes in color with reflectance angle, that simple chemistry based paints could never achieve. We are developing new computer graphic reflection models that can reproduce these beautiful color appearances in computer generated pictures.

Simulation of metallic and pearlescent paints.

Per Pixel Shaders — Recent developments in computer graphics hardware have dramatically increased the amount of computation that can be performed for each pixel on the display screen. This has made it possible to evaluate a complex surface reflection model at each point of a polygon and to render that polygon at interactive rates. We are using the emerging shading languages for this hardware to write programs for shaders that implement advanced computer graphic reflection models such as those being developed for the previously mentioned physics based paints and coatings.

CACAD Programs — The ability to evaluate a complex surface reflection model at interactive rates makes it possible to write Computer Aided Color Appearance Design (CACAD) programs. Instead of simply producing a photorealistic picture of an existing color appearance, we are developing true design programs that allow the color technologist to manipulate the parameters of advanced reflection models in real-time and evaluate color appearances that have never been manufactured. When combined with the possibilities presented by the emerging physics based paints and coatings described above, true CACAD becomes possible.

CACAD program for design of goniochromatic colors.

High Dynamic Range Displays — The study of color appearance using television monitors or liquid crystal displays is primarily constrained by the limited dynamic range of these desktop displays. This is a major concern because the specular highlight, which provides most of the cues regarding the shininess of a surface, cannot be correctly rendered without clipping or adjusting it to bring it back within the dynamic range of the CRT. To overcome this problem, we are investigating the construction of a high dynamic range display using emerging projection and display technologies.

Use of back projection to prototype a metallic surface finish.

Prototyping Surface Finishes — Physical hard copy of Computer Aided Geometric Designs is accomplished using stereolithography and numerically controlled machining. Unfortunately neither of these two rapid prototyping techniques can duplicate the surface finish and color appearance of a completed design. We are conducting research that extends the idea of physical hard copy to include the simulation of color appearance on the surface of the prototype. We will accomplish this by investigating the projection of video onto complex shapes that are tracked in a three dimensional environment.