Thoughts on surfaces
By Eigil Bakdal Jorgensen
A package came through the mail today. Inside it was a fifty-millimeter steel ball. It was perfectly polished like a mirror. The person who received it could see themselves in the reflection of the ball. They could actually see almost the whole room they were standing in reflected in the steel ball. Their face was slightly distorted, as if captured through a fish-eye lens, and when holding it in their hand, the reflections of their fingertips took up half of the tiny image formed on the spherical surface.
When looking into the ball, they were reminded of something their dad once told them. If you take a photo of a ball with a reflective surface, you can then use that photo in a 3D program to perfectly replicate the lighting of whatever room or area you were in when you took it. By “unwrapping” the mirrored ball so that you are technically inside it, all the reflections, highlights, and shadows of every 3D object placed in that scene will be perfectly replicated as they would be in the room where you took the original photo. In this case, the dim hallway where the person stood, looking at the ball.
Looking at the fingertips meeting the surface of the cold, smooth steel ball, the person lingered on the contrasting textures of the different materials. In a 3D program, these textures would have been flat images wrapped around the surface of the model of the hands and the steel ball. The ball's surface is a difficult, but fairly possible, shape to map out. We have seen it on a globe. The surface of a person is a bit more difficult. All the way from the fingertips down to between the toes is one cohesive surface. How far up into the nose counts as surface on a person? If you were a tiny animal crawling around on the surface of a human, would you even notice the difference between an arm and up the nose?
The person wondered how far you would have to stick a pencil up a nostril for it to be considered inside the body, and thought about another time they saw a CPR dummy (the kind you train mouth-to-mouth resuscitation on) turned inside out, where the nostrils and the mouth normally would be, three long fleshy tubes emerged instead, about half a meter long. The inside of the mouth and nose goes deep on a dummy like that.
If a tiny animal were to crawl all the way across the person’s body, it would eventually pass onto the clothing, making the clothes part of the same surface. The animal would start on the lower back, then crawl all the way up under the T-shirt (still on the skin), then at the collar (where the skin and the T-shirt meet) crawl onto the inside of the T-shirt and go all the way down again, then out onto the outside of the T-shirt and up, finally reaching the head of the person. If you turned a person wearing a T-shirt inside out, the open space between the T-shirt and the skin would become a positive space and stick out like the mouth of the CPR dummy.