Step-driven character animation derived from animation data without footstep information

A computer program product for generating a sequence of movements of a simulated character for use with a computer system having a display and a user input device, the simulated character being a representation of a real or imaginary creature comprising a plurality of simulated body parts attached at prespecified attachment points, the plurality of simulated body parts including one or more extremity, the computer program product comprising:

• program code defining a process of displaying a view of a space on the display coupled to the computer system;
• program code defining a process of accepting signals from the user input device coupled to the computer system, the signals specifying a location in the space and a time for each footstep of a plurality of footsteps, a footstep being a placement of one of the one or more extremity in the space;
• program code defining a process of deriving at least one additional footstep for the plurality of footsteps from motion data representing motion of the simulated character;
• program code defining a process of displaying for each footstep, a footprint indicating the location of the footstep in the space;
• program code defining a process of determining a plurality of parameters for the entire sequence of movements;
• and
• program code defining a process of generating a series of keyframes, wherein the series of keyframes collectively describe a sequence of movements of the simulated character along a coherent trajectory which sequence simultaneously satisfies the constraints of (1) having the one or more extremity coincide with the plurality of footsteps in space and time, and (2) the plurality of parameters on the plurality of simulated body parts, wherein at least one parameter of the plurality of parameters affects the content of a plurality of keyframes in the sequence of keyframes;
• and
• a computer-readable medium on which the program codes are stored.

A method of generating a sequence of movements of a simulated character in a computer system, the simulated character being a representation of a real or imaginary creature comprising a plurality of simulated body parts attached at prespecified attachment points, the plurality of simulated body parts including one or more extremity, the method comprising the steps of:

• displaying, using the computer system, a view of a space on a display coupled to the computer system;
• accepting signals from a user input device coupled to the computer system, the signals specifying a location in the space and a time for each footstep of a plurality of footsteps;
• displaying on the display for each footstep a footprint indicating the location of the footstep in the space;
• determining a center of gravity for the simulated character at each footstep;
• and
• generating, using the computer system, a series of keyframes, wherein the series of keyframes collectively describe a sequence of movements of the simulated character along a coherent trajectory which sequence simultaneously satisfies the constraints of (1) having the one or more extremity coincide with the plurality of footsteps in space and time, and (2) having the center of gravity obey laws of Newtonian Physics within the space.