Making Digital Painting Organic
Author(s): Nelson Siu-Hang Chu.
PhD Thesis: Hong Kong University of Science and Technology, August,
2007.
[BibTeX] 
Abstract:
In this thesis I present physically-based techniques for building real-time digital painting
tools. In particular, I focus on two components that are most needed in existing paint
systems: 3D brush modeling and water-based paint simulation. A 3D deformable brush
model is crucial in generating organic brush strokes. When paired with a proper input
device, such a brush model also allows true-to-life control of stroke creation because
users can see how the brush deforms in response to their manipulation while painting.
Existing paint programs do simulate various paint media including charcoal, oil,
and watercolor. However, water-based media like Eastern ink and Western watercolor
are the most unsatisfactory due to their inability to produce natural-looking marks,
especially those with flow effects. In the second part of my thesis, I present a technique
based on a relatively new computational fluid dynamics method called Lattice
Boltzmann to simulate water-based paint media. Many of the existing real-world artistic
effects as well as novel ones are achievable with this approach.