Charles F. Rose

Verbs and adverbs: multidimensional motion interpolation

This article describes methods and data structures used to leverage motion sequences of complex linked figures. We present a technique for interpolating between example motions derived from live mo...The article describes a system for real-time interpolated animation that addresses some of these problems. Through creating parameterized motions-which the authors call verbs parameterized by adverbs-a single authored verb produces a continuous range of subtle variations of a given motion at real-time rates. As a result, simulated figures alter their actions based on their momentary mood or in response to changes in their goals or environmental stimuli. For example, they demonstrate a walk verb that can show emotions such as happiness and sadness, and demonstrate subtle variations due to walking up or down hill while turning to the left and right. They also describe verb graphs, which act as the glue to assemble verbs and their adverbs into a runtime data structure. Verb graphs provide the means for seamless transition from verb to verb for the simulated figures within an interactive runtime system. Finally they briefly discuss the discrete event simulator that handles the runtime main loop.

Efficient generation of motion transitions using spacetime constraints

This paper describes the application of space time constraints to creating transitions between segments of human body motion. The motion transition generation uses a combination of spacetime constraints and inverse kinematic constraints to generate seamless and dynamically plausible transitions between motion segments. We use a fast recursive dynamics formulation which makes it possible to use spacetime constraints on systems with many degrees of freedom, such as human figures. The system uses an interpreter of a motion expression language to allow the user to manipulate motion data, break it into pieces, and reassemble it into new, more complex, motions. We have successfully used the system to create basis motions, cyclic data, and seamless motion transitions on a human body model with 44 degrees of freedom. Additional

Shape by example

Modern modeling systems enable artists to create highquality content, but provide limited support for interactive applications. Although complex forms can be constructed either by hand or with geometry capture technologies, once they are created, they are difficult to modify, particularly at runtime. Interpolation provides a way to leverage artist-generated source material. We present a methodology for efficient runtime interpolation between multiple forms. Linear plus radial basis functions provide the key mathematical support for the interpolation. Once our system is provided with example forms, it generates a continuous range of forms we call a shape. We also apply the shape interpolation methodology to articulated figures and human face models to create smoothly skinned figures that deform in natural ways. Unlike previous formulations, the one presented here is efficient enough to support interactive design of the abstract interpolation space as well as support runtime interpolation of the forms in interactive applications such as games. The reader is encouraged to visit the project’s website for more information and late-breaking results at http:\\research.microsoft.com\graphics\hfap.

Artist-Directed Inverse-Kinematics Using Radial Basis Function Interpolation

One of the most common tasks in computer animation is inverse‐kinematics, or determining a joint configuration required to place a particular part of an articulated character at a particular location in global space. Inverse‐kinematics is required at design‐time to assist artists using commercial 3D animation packages, for motion capture analysis, and for run‐time applications such as games.