Dawn of Ancient China

Wan-Yen Lo, spring 2007

wanyen at graphics dot ucsd dot edu

Introduction


One attracting characteristic of computer graphics is the ability to recover things that no longer exist in the real world, and to visualize those that only live in our imagination. From this class, we have learned so many techiniques for rendering realistic images, so I am looking forward to apply these techniques to reappear the beauty of ancient Chinese architecture. In this way, I planned to build a street in Tang Dynasty, which began two thousand years ago and was the most prosperous dynasty in Chinese history.

Modeling


Since Tang dynasty has disappeared for more than two thousand years, it is hard to imagine what the street exactly looks like. I started by looking for pictures on the internet, and found some inspirable images.

Then I started building my scene in 3DS MAX. This is my first time using 3DS MAX, so it took me some time to build the whole scene.

I didn't create every detail of the houses. Thanks to Wei-Ting Peng for giving me many beautiful 3D models. The models were nicely created, so that I can easily modify everything in 3DS MAX. There are about 130,000 triangles in total in the final scene.

Procedure Textures & Bump Mapping


I used the Worley noise to create the effects of flagstone. To make it more realistic, I applied a turbulence function to make the stone less smooth. The turbulence funciton is also used to create the soil under the houses and stones. With the bump mapping, the stones look like paved on the soil, rather than just flat.

HDR Environment Mapping


After laying out the floor, I decided to reconstruct the street in the fresh air, just after the dawn. The sun is rising in the east, and it seems that a hopeful day is going to start. To achieve this, I used a spherical HDR environment map of a clear sky, which is found on the Internet.

Photon Mapping & Soft Shadows


Since the sun is far away, I used a directional light to illuminate the scene. In this way, indirect illumination is important for the buildings, so I implemented the Photon mapping. I really like the fact that the Photon map can capture many subtle light changes, and thus I used Photon map for all directional & indirectional illumination. For my final image, there are about six millions of Photons stored in my scene. The left image demonstrate the light changes on the building, and the right image shows that soft shodows can be produced directly by only looking up the Photon map. Thanks to Will Chang for lending me the book!

Participating Media / Volumetric Scattering


When I created the scene, I always imagined there is a light passing through the door. For this purpose, I decided to implemet volumetric scattering. Here are some results of my simulation.

To achieve this effect, I placed a bounding box of atmosphere. Since the sun just rose in the east, the laterns hang in front of the grand hotel were still lit. I also used the volumetric scattering to capture such tranquility. Thanks to Craig Donner for answering me so many questions about details in implementations!

Final Image