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 so we can see their interiors. It is another way that the shapes can be explored and leads to a visual effect that has something in common with the animation of images of the interior of the human body generated by medical scanners. We see inside something that would normally be hidden and what we can see changes as we move our viewpoint through it. Some of the outsides of the shape can also be seen, so it is also a bit like seeing a log of wood 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 views of slices through granite gathered from the Antarctic.

One way to understand how these images are made 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 something of how the cells became arranged as the tree grew.

The forms in my work are made by trails or paths through space that are represented by shapes arranged along the routes. These markers can be considered as being a bit like the cells in wood. 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’. So, when the graphic display of the work is calculated it effectively slices through the forms, revealing the inside of the shapes and this creates the patterns that can be seen. 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, as the viewpoint or the object move, 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 kind of 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 also be seen when 3D printers build up an object layer by layer.

[first published March 22 2022, edited July 25 2022]