Tony DeRose, Michael Kass, Tien Truong
August 1998
The creation of believable and endearing characters in computer graphics presents a number of technical challenges, including the modeling, animation and rendering of complex shapes such as heads, hands, and clothing. Traditionally, these shapes have been modeled with NURBS surfaces despite the severe topological restrictions that NURBS impose. In order to move beyond these restrictions, we have recently introduced subdivision surfaces into our production environment. Subdivision surfaces are not new, but their use in high-end CG production has been limited.
Here we describe a series of developments that were required in
order for subdivision surfaces to meet the demands of high-end
production. First, we devised a practical technique for
constructing provably smooth variable-radius fillets and blends.
Second, we developed methods for using subdivision surfaces in
clothing simulation including a new algorithm for efficient
collision detection. Third, we developed a method for
constructing smooth scalar fields on subdivision surfaces, thereby
enabling the use of a wider class of programmable shaders. These
developments, which were used extensively in our recently
completed short film Geri's game, have become a highly
valued feature of our production environment.
Available in the Proceedings of SIGGRAPH 1998.