We present a method for dynamically generating an efficient texture bitmap and its associated UV-mapping in an interactive texture painting system for 3D models. Typical 3D texture painting programs update texture 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 level. This technique can be efficiently implemented 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.
Publications
Takeo Igarashi, Dennis Cosgrove
"Adaptive Unwrapping for Interactive Texture Painting"
2001 ACM Symposium on Interactive 3D Graphics, I3D2001,
Research Triangle Park, NC ,
March 19-21, 2001.
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