

Our next focus was being able to render Maya scenes in Radiance. Here, we ran into some difficulties. Radiance offers two options for converting obj files into Radiance-compatible files: obj2mesh and obj2rad. obj2mesh compiles the obj file into a Radiance triangle mesh, and is supposedly more efficient and allows the use of local uv coordinates. On the other hand, obj2rad takes the obj file and compiles it into a Radiance scene. We attempted to use the obj2mesh method at first with a simple lamp model, but were unable to get anything to show up in the render window. We plan on continuing to troubleshoot this this week, and were thinking of also trying obj2rad, just to have a starting point.
Other than the tutorials and reference manual on the Radiance website, we haven't been able to find a lot of other documentation on Radiance. We did come across Render Toolbox, a set of tools that simplifies the process of rendering Maya files with Radiance. According to its wiki page, the project is in a beta stage and is headed by David Brainard, a psychology professor at Penn. If we are unable to resolve our problems with obj2mesh and obj2rad, we may contact Professor Brainard for help.
We also found two archaelogical papers: "High Fidelity Rendering of the Interior of an Egyptian Temple" by Ivana Rudolfova and Veronica Sundstedt and "High Fidelity Rendering of Ancient Egyptian Gold" by Carlo Harvey. Both of these papers have been useful examples of rendering Maya scenes; interestingly, we noticed that both of these papers used the obj2rad method.
Giulio Antonutto's Radiance website has been helpful as well; the website contains basic tutorials and links to Radiance workshops, where we found a PDF presentation on how to run Radiance on Windows. According to this presentation, there are five different Radiance distributions for Windows: Rayfront (development stopped in 2003), Adeline (development stopped in 2002), Desktop Radiance (development stopped in 2001), and the Cygwin and Mingw binaries, both of which are almost up to date. Following instructions, we installed Cygwin on a PC running Windows XP, and were able to successfully run and render a simple scene in Radiance. Previously, we had planned to conduct benchmarking tests between the Windows version and Linux version of Radiance. This was temporarily placed on hold when Cory informed us that he wasn't able to get the Windows versions to run. It now may be unncessary to conduct benchmarking tests; Cygwin allows the Linux version of Radiance to be run on Windows, so the same version of Radiance is essentially being used on both operating systems.
On February 5, we met with Professor Holod at the University of Pennsylvania Museum of Archaelogy and Anthropology to examine artifacts of ancient glass and a small candelabra. We plan to meet with Professor Holod again soon to take measurements of these glass artifacts with the spectroradiometer, and will also be obtaining scans of Islamic glass lamps from the book Glass of the Sultans later this week. Once we have the scans and measurements, we can begin modeling and texturing.
From our meeting on February 12, Dr. Badler informed us that we would receive the spectroradiometer sometime this week. Since we only have it until February 27th, one of our priorities till then will be taking measurements of the glass, paraffin, beeswax, olive oil, etc.
Becky and I also looked into flame simulation. As discussed at the meeting, one of the problems with flame simulation is that it is important to have an accurate physically based simulation of the candle for the photon mapper. Professor Safonova told us that unfortunately, the priority in computer graphics for flame simulation has been placed on a realistic appearance instead. Becky and I will be looking into some papers on this problem; so far, our list consists of:
- "Digital Imaging-Based Three-Dimensional Characterization of Flame Front Structures in a Turbulent Flame" by Bheemul, Lu, and Yan
- "Extending the Photon Mapping Method for Realistic Rendering of Hot Gaseous Fluids" by Kang, Ihm, and Bajaj
- "High Fidelity Lighting of Knossos" by Ioannis Roussos and Alan Chalmers
- "Simulation and Animation of Fire and Other Natural Phenomena in the Visual Effects Industry" Nguyen, Enright, and Fedkiw
- "Enhanced Illumination of Reconstructed Dynamic Environments Using a Real-Time Flame Model" by Bridault-Louchez, Leblond, and Rousselle
The paper "Visual Simulation and Animation of a Laminar Candle Flame" by J. Raczkowski also came up in our search, but we were unable to find a copy of the paper.
We also got in touch with the newest member of our group, Kaikai Wang. We gave him Brian Summa's photon mapping code, and plan to have some code review sessions soon.
Finally, we recently discovered that Radiance has a photon mapping extension, and plan on looking further into this for the upcoming week.