1. Introduction
My final project for CS563
will consist three parts: 1) to replace Maya’s diffuse and ambient shading, 2)
use High Dynamic Light Probes to light the scene, 3) use additional area light
with different polygonal shapes within the scene. To replace Maya’s default
diffuse and ambient shading, I will use Spherical Harmonics Lighting, which
will consist of writing a C++ plugin or developing a script using Maya’s Mel
scripting language. Second part of my project will involve using Paul Debevec’s
HDRShop program to produce a Maya Mel script representing a High Dynamic
Range area light within the scene. In the final part of the project, I will use
additional polygonal shaped area lights to produce different lighting effects
within the scene. Additionally, within the scene, I would like to add in an
exposure tool that will allow adjustments of the exposure levels generated from
the High Dynamic Range lights.
2. Previous Work
Robin Green of Sony Computer Entertainment
America gave a talk at the Games Developers Conference in 2003 entitled
“Spherical Harmonic Lighting: The Gritty Details”. In this talk, he gave a description of SH, the benefits of using
SH in games, and how it could be implemented in conventional rendering engines.
His examples demonstrated diffuse and ambient contributions to a rendered scene
while alpha blending the normal Phong specular highlights. In my project, I
will try to reproduce his claim that “Spherical Harmonics can be a drop in
replacement for normal diffuse and ambient shading”.
Secondly,
Paul Debevec has made High Dynamic Range images a popular new advancement in
Computer Graphics. He has also developed a software tool for creating and
manipulating High Dynaic Range images called HDRShop as well as several
light probe image examples. I will use this tool to manipulate and
export a High Dynamic Range image into a format that is Maya friendly (a Mel
script).
Finally,
a paper written by David Warn titled “Lighting Controls For Synthetic Images”
describes area lights and the advantages to area lights over point lights,
specifically lighting controls. This paper discusses several different controls
for area lights such as, direction, shape, concentration, and color as well as
the effects these controls have on materials. I will attempt to replicate these
controls to generate the same effects described in the paper.
3. Deliverables
The result of the final
project will be several rendered images that will include a complex polygon
model lit by a High Dynamic Range light probe image, several area lights, and
High Dynamic Range exposure controls. The High Dynamic Range light will be
approximated using Spherical harmonic Lighting so that several additional
images will be rendered with normal diffuse and ambient shading for comparison.
The rendered images will be rendered in Maya 4.0 with the light probes
generated and converted from HDRShop to a compatible Maya format (a Mel
Script). The development of the Maya plugin for the Spherical Harmonic Lighting
will be developed in Visual Studio C++ with a special Maya programming
interface provided by Alias|Wavefront.