This paper presents a method for modeling seashells, suitable for image synthesis purposes. It combines a geometric description of shell shapes with an activator-inhibitor model of pigmentation patterns on shell surfaces. The technique is illustrated using models of selected shells found in nature.

Keyframing is a popular method for animating articulated figures because it allows artistic expressiveness by providing control to the animator. The animator defines a movement by providing a set of poses. The motion is then obtained by simply interpolating between these keyframes, typically with cubic splines. The drawback of this process is that it requires significant effort from the animator. Defining a movement often requires a high level of detail to ensure that the interpolation curves induce the desired motion. In particular, the animator has to focus on avoiding collisions between the limbs of his or her articulated figure. The paper describes a new interpolation method producing autocollision-free paths. A first interpolation is computed using any classical inbetweening method. Autocollisions are then identified and corrected if necessary. At some collision times, autocollision-free sub-keyframes are automatically generated using geometric properties. They are then used for obtaining an autocollision-free interpolation. Experimental results using a human model show that the animator can reduce the level of detail needed for describing a movement and still get realistic results at interactive speeds.

This paper presents a symbolic approach to the computation of blend surfaces across piecewise polynomial and rational surfaces. Curves in the parameter space of the primary surfaces can be specified as the rail curves, also known as trimlines, of the blend. Several techniques which require various levels of user interaction are presented for defining the cross boundary tangent curves along the rail curves. The resulting blend is represented as a polynomial surface having tangent plane continuity with the primary surfaces to an accuracy bounded only by the machine precision. Also presented is a normalization method that approximates a unit vector field, an approach that might benefit other applications such as offset approximation and animation curve construction. Key Words: Symbolic computation, Hermite interpolation, Fillets and Rounds, Blends, Reparameterization. 1 Introduction Blend surfaces are ones which smoothly blend two adjacent surface boundaries. In addition to be...

SPAM (Simulation Platform for Animating Motion) is a simulation software system designed to address synchronization issues pertaining to both animation and simulation. SPAM provides application programs with the manipulation, con guration, and synchronization tools needed when simulations are combined to create animations. It is designed to be used as the glue between applications that supply lists of the parameters to animate and the callback procedures to invoke when a user wishes to modify the parameters directly. SPAM does not impose a particular model of simulation, accommodating keyframing, physical simulation, or avariety of other models, providing they can be abstracted

This paper presents a symbolic approach to the computation of blend surfaces across piecewise polynomial and rational surfaces. Curves in the parameter space of the primary surfaces can be specied as the rail curves of the blend. Several techniques which require various levels of user interaction are presented for dening the cross boundary tangent curves along the rail curves. The resulting blend is represented as a polynomial surface having tangent plane continuity with the primary surfaces to an accuracy bounded only by the machine precision. Also presented is a normalization method that approximates a unit vector eld, an approach that might benet other applications such as oset approximation and animation curve construction. Key Words: Symbolic computation, Hermite interpolation, Fillets and Rounds. 1 Introduction Blend surfaces are ones which smoothly blend two adjacent surface boundaries. In addition to being a modeling tool, blend surfaces are used to emulate manu...

a 2 1 + a 2 + ae 0 ' \Gamma a +Da @ 2 a @x 2 @s @t = oe \Gamma aes ` a 2 1 + a 2 + ae 0 ' \Gamma s +Ds @ 2 s @x 2 (8) The activator, with the concentration a, diffuses along the x-axis at the rate Da and decays at the rate . Similarly, the substrate, with the concentration s, diffuses at the rate Ds and decays at the rate . The substrate is produced at a constant rate oe. Production of the activator is an autocatalytic process, proportional to a 2 for small activat

that I have read this thesis and that in my opinion it is fully adequate,

that I have read this thesis and that in my opinion it is fully adequate,

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