Assignment 1

Build/Installation

I installed pbrt on my Intel-based MacBook Pro running Mac OS X 10.4. The build and installation instructions were straightforward, especially after installing OpenEXR using Fink. However, I ran into some issues when building the pbrt tools. I ended up having to further modify the Makefile under the tools directory to work around unrecognized flags passed to the linker.

Rendering Process

In order to speed up the rendering process, I lowered the resolution to 200 x 200 pixels, used 1 sample per pixel, and 1-2 area samples for test images. Rendering time was relatively fast for the first three configurations. For the fourth configuration, I rendered each light source separately until they looked right individually before rendering the final image with all four lights.

I found it easiest to start with placing the light source in the general position it was supposed to end up, and then incrementally tweaking one parameter at a time to see how it would affect the scene. Whenever I got ahead of myself and changed several parameters at a time, it would take a bit to sort out which changes were satisfactory and which ones were getting me further from what I wanted.

I was initially confused by the main light in the fourth configuration, and spent a long time trying to tweak the parameters of a spot light to get the correct lighting and shadowing on the model. Once I started using an area light, I got much more satisfactory results with the softer shadowing.

Experimentation

What I found helpful throughout the assignment was placing the camera at different points around the scene. This helped me get a better perspective on the positioning of the light sources as well as understanding the effects of geometric transformations. I also experimented a bit with tweaking the color and size of different lights to see the effect on the model.