Controller for jumping animations to achieve target positions

Abstract

Animating a character for video games and films is difficult and time consuming, requiring hours of artist labor to produce each animation. These animations are set and inflexible, requiring changes to the animation or sometimes fully new animations to suit new characters or situations for natural looking movements. Jumping is one such animation, where the size, mass, strength, and environment affect the movement of the character. Traditionally these animations are produced by manually posing the character for certain key frames and interpolating between the frames to produce a smooth animation. The more detailed or lengthy an animation, the more work required to specify it. Physics-based simulation for animation production can reduce this work, creating animations for a variety of situations based on constants set for the character and environment. These animations can then be easily recreated or adjusted for different environments by changing the constants set for generation.

This thesis work presents a simulation-based method of control for a character, focusing on the lower body, to produce jumping animations for a variety of situations and body parameters. Two methods of simulation are described, one using a torque calculation and the other using an energy calculation to determine poses for the character. My simulation takes as input a mesh representing the character, a tree of joints describing the skeleton, a set of muscles, mass assigned to each limb of the body, and a description of the desired path through desired timings, gravity, and desired displacement. An inverse kinematic solver is used to aid in posing the character.

Contributions of this thesis include an implementation of a simulation to produce jump animations in Unity3D, a description of character poses based on torque as well as another based on energy, a sampling-based method for choosing a target position, and visualization of the produced animations in several ways to aid in debugging, analysis and presentation.