For quite a while now I have been making some images and animations by moving the graphic objects generated by my programs so that they appear to be being sliced through. It is another way that the shapes generated by my programs can be explored and leads to a visual effect that has something in common with the animation of images of slices through the human body seen with medical scanners. We see inside something that would normally be hidden, which changes as we move our view through it. In my works we can also see some of the remaining outsides of the shape so it is also a bit like seeing a joint of meat after it has been sliced through, or a salami, or in fact anything that has been sliced through. I once made some animations based upon microscopic slices through granite gathered from the Antarctic.
One way to understand how I make these images is to think about how the patterns on the surface of wood are created. Wood is made up of many cells joined together. If we cut through it along their length, we get one kind of pattern and sawing across the cells we get different patterns. They all reveal how the cells became arranged as the tree grew.
The trails that make up the forms in my work are represented by shapes arranged as markers along the routes. These markers can be considered as being a bit like the cells in wood. When the graphic display of my work is calculated it is possible to effectively slice through the forms, revealing the inside of the shapes and this creates the patterns that can be seen. The algorithm that determines how to display the forms is made to ‘clip’ anything that gets within a certain distance of the viewpoint of the ‘virtual camera’. It is as if the shapes have been sawn through at a certain distance from the viewer. As this view is continually recalculated as the program runs, if the camera or object are moved, or the distance at which the clipping is to take place is changed, the patterns also change.
Usually, where computer graphics is used to create images, in games or movies, this clipping would be considered a ‘glitch’. Having a graphic object representing, say a human actor, sliced through, revealing how it is simply an illusion created using geometrical data and clever rendering techniques, is not desired as it interrupts the audiences willing suspension of disbelief. The effect is not always avoided as it can be exploited, for example to simulate the creation of an object via an advanced technology or magic.
These kinds of patterns can be seen as 3D printers build up an object layer by layer.