Implicit painting of CSG solids

Ergun Akleman Visualization Laboratory Department of Architecture Texas A&M University

Abstract

Implicit painting is a non-photorealistic rendering method for painting implicitly represented CSG solids. The method is based on the fact that when a difference equation is applied to a set of particles these particles will move in 3D space. We view the motion of the particles as the motion of the hands of several painters and the trajectories of the particles as long unbroken brush strokes, over the boundaries of solids obtained by set-operations. These boundary surfaces are used as if they are the canvases of painters. The difference equations provide the trajectories of the brushes, brush and paint types. We consider this painting as a creative or `artistic' process in which the resulting artwork can be an image, a stereo image or even an animation that shows the painting process.

Motivation

There is much recent interest in both computer graphics research community and the animation industry in the development of new techniques for creating artistic or natural looking images. We believe the process of oil painting gives us a good paradigm to obtain both artistic or natural worn and torn images. The richness of painted images comes from the application of many layers of different paints over the canvas by the painter. Our goal is to obtain the same kind of richness that comes from the hard work of the artist by creating continuous motion of brushes over the boundaries of solids obtained by set-operations.

Meier obtained a painting effect by attaching brush images to static particles. In this work, we attach objects, instead of images, to brushes (particles) relying on the continuous motion of brushes to produce the desired look. Although, this painting idea is based on oil painting, implicit paintings are different from oil paints in two ways.

• When painters do not paint a portion of canvas we can still see the canvas. However, in implicit surface paint, if a painter does not paint a certain portion of the surface, it leaves a hole which gives an interesting effect.

• Implicit paints can be considered as sculptures in addition to paintings. Therefore, these sculptures can be visualized in 3D by using stereo views. Such stereo views reveals the potential of implicit painting as a new painting paradigm. These paintings can also be transformed into stereo photographic prints.