Homework 1: Lighting Design in PBRT
All final configurations were rendered with two subsurface subdivisions. In order to quickly adjust the lighting conditions and camera position and orientation, I performed a number of trials, rendering the image in low resolution (60x60) with few samples and subdivisions, tweaking one light at a time. Once the final renders were made, I made minor changes to their exposure using the OpenEXR photoshop-plugin. Here's a summary of what I did for each configuration, including some things to better reproduce the sample images:
In this configuration the light was positioned slightly below and in front of the face. I continued to direct the light at the origin, though reduced the cone radius to retain some shadows along the boundaries. This helped better reproduce the target image.
I rotated the area light source so that its normal faced the left side of the face (our right), where the light was subsequently placed beside. I also made the radius smaller to keep the light subtle and not overwhelm the front of the face.
I used the same settings for the area light in configuration 2 with the exception of the radius, which I increased slightly. The point light was positioned in front of the face, over by its right side. To keep the top of the head lit, the light was repositioned slightly along the y-axis.
The camera was moved a couple units to the right to view the model at a good angle, while the main light was positioned slightly above the head by the right side of the face and pointed near the forehead. The fill light was located just to the right of the camera and rotated to face the model. The accent light was placed over and behind the head (and slightly to its left to better reproduce the corresponding sample image in the handout). Finally, the background light was placed behind and below the head, again on its left side. It was pointed at the wall at a moderately upward angle to hit the wall just right.