This is an interactive texture painting system for 3D models
that dynamically generates an efficient texture bitmap and
its associated UV-mapping. Typical texture painting
programs update texture the bitmap only as the user paints
strokes on the 3D view. The user defines the underlying
UV-mapping from 3D geometry to 2D bitmap before
painting, and this mapping remains unchanged during the
painting. However, a predefined UV-mapping can cause
distortion at arbitrary locations, and unpainted areas in the
bitmap waste memory. To solve these problems, we
propose an adaptive unwrapping mechanism where the
system dynamically creates a tailored UV-mapping to
newly painted polygons during the interactive painting
process. As a result, the distortion of brush strokes
disappears, and the resulting texture bitmap is more
compact because the system allocates texture space only for
the painted polygons. In addition, this dynamic texture
allocation allows the user to paint smoothly at any zoom
Ievel. This technique can be eficiently impIemented using
standard 3D rendering engines, and the painted models are
stored as standard textured polygonal models. We
implemented a prototype system, called Chameleon, and
our user experience suggests that our technique is very
useful for simple painting by casual users.