= Final Project Proposal (Draft): LeeHendrickson, RyanSmith = == Illustrative Pictures == http://thumb.shutterstock.com/photos/display_pic_with_logo/1643/1643,1112161307,1.jpg http://www.geocities.com/CapeCanaveral/Hangar/7195/lavadr1.jpg == Project Goals == We wish to model the flow of lava or a molten material such as steel. Materials such as lava have black body radiative characteristics that cause them to act as emissive light sources. Furthermore, the surface of a molten material can change over time as its temperature changes, varying from smoothly flowing and extremely emissive to much cooler and therefore darker. == Motivation == Visually, an active lava flow or a stream of molten steel is very compelling, as it is both dramatic and unique. This is not something an person has much everyday exposure to, and as such a certain sense of awe is instilled by this phenomenon. On a technical side, PBRT currently only supports "simple" light sources such as a point light, an area light, or an environment map. Adding support for black body radiators opens the door to many more such materials. We would also like to enrich PBRT's procedural generation algorithms with more complicated, and physically based versions. Since the temperature of a molten material has some direct relationship with time, seeding the generating algorithms with a time factor could lead to being able to produce some compelling animations. == Key Technical Challenges == 1. Black body radiation. a. Computing (physically) correct emissive characteristics of material (based on temperature). b. Varying between the emissiveness of the black body at high temperatures and a possibly more traditional BRDF at low temperatures in a continuous and plausible fashion. c. Actually lighting the environment according to the calculated emissiveness of the black body (photon mapping?) 2. Procedural generation of surface features. a. Designing a procedural algorithm to generate a visually appealing and plausible surface temperature (and thus color) for the flow. This algorithm should be seeded such that certain known characteristics can give rise to a more physically correct surface. b. Possibly in later stages using a procedural algorithm to generate the geometry of the material itself rather than a fixed model. c. The procedurally generated surface features should be able to be fed to the black body radiation algorithm such that emissiveness is directly related to those surface features. 3. Modeling an appropriate environment. a. To be able to visually recognize that the flow is a black body radiator there must be at least some objects in the environment that can realistically reflect the emitted light. b. However, given the time frame of the project this must be balanced with the need to otherwise keep the scene as simple as possible. == Outline of Approach == Given the different components of the project there is a natural delineation of work across technical challenges 1 and 2 above. The focus will be on rapidly prototyping each component in PBRT, with Ryan focusing on black body radiation, Lee on procedural generation, and both on modeling. Once these proof-of-concepts are completed a more full fledged implementation will begin, keeping the "API" between the two features as clean as possible to allow integration of the results in both areas to produce the final image. Modeling the environment and the flow's geometry will most likely be done through a package such as Maya to start to give us objects we can quickly use. == References == http://en.wikipedia.org/wiki/Blackbody_radiation http://www-imagis.imag.fr/LAVA/ http://galileo.phys.virginia.edu/classes/252/black_body_radiation.html http://mrl.nyu.edu/projects/texture/ http://freespace.virgin.net/hugo.elias/models/m_perlin.htm