Detail-Preserving Paint Modeling for 3D Brushes

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               ***Joint Seminar***
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The Hong Kong University of Science & Technology

Department of Computer Science and Engineering
Center of Visual Computing and Image Science
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Speaker:	Dr. Nelson Chu
		Senior Software Development Engineer
		Microsoft Corp.

Title:		"Detail-Preserving Paint Modeling for 3D Brushes"

Date:		Wednesday, 8 June 2011

Time:		3:00pm - 4:00pm

Venue:		Room 3311 (via lifts 17/18), HKUST

Abstract:

Recent years have witnessed significant advances in 3D brush modeling and
simulation in digital paint tools. Compared with traditional 2D brushes, a
3D brush can be both more intuitive and more expressive by offering an
experience closer to wielding a real, physical brush. To support popular
media types such as oil and pastel, most previous 3D brush models have
implemented paint smearing and mixing. This is generally accomplished by a
simple repeated exchange of paint between the 3D brush and 2D canvas, with
the paint picked up by the brush typically mapped directly onto the brush
surface. In this talk we demonstrate that both repeated exchanges and
direct mapping of paint onto brush surfaces are sub-optimal choices,
leading to excessive loss of color detail and computational
inefficiencies. We present new techniques to solve both problems, first by
using a canvas snapshot buffer to prevent repeated paint exchange, and
second by mapping brush paint onto a 2D, resolution-matched pickup map
that sits underneath the brush, instead of mapping onto the 3D brush
itself. Together, these act to minimize resampling artifacts, helping to
preserve fine streaks and color details in strokes, while at the same time
yielding improved efficiency by never sampling the brush more densely than
necessary. We demonstrate the effectiveness of our method in a real-time
paint system implemented on the GPU that simulates pastel and oil paint.
Our method is simple and effective, and achieves a level of realism for
these two media not attained by any previous work.


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Biogrpahy:

Nelson Chu is both a visual artist and a software engineer. From 2001 to
2007 he focused on the research and development of a novel Chinese ink
painting/calligraphy system, which redefined natural-media painting in the
field of computer graphics. MoXi, the resulting system, has been used to
produce visual effects for films or TV commercials, notably in the Opening
Ceremony of the 2008 Beijing Olympics. MoXi was also licensed to
industrial giants Adobe and Sony in 2006 and 2007 respectively. Nelson
currently works for Microsoft on digital painting system. A preview of the
technology is now showing at the Museum of Modern Art (MoMA) in New York
till August 2011. Nelson obtained his PhD in Computer Science from the
Hong Kong University of Science and Technology in 2007.