US 6,191,798 B1 · Limb coordination system for interactive computer animation of articulated characters

Abstract

A method and apparatus for interactively controlling and coordinating the limb movements of computer-generated articulated characters with an arbitrary number of joints. On-line computational methods are used for animating limb movements of articulated characters by solving associated forward and inverse kinematics problems in real time subject to multiple goals and constraints. The methods provide computer animated characters with fully interactive goal-directed behaviors, such as bipedal walking, through simultaneous satisfaction of position, alignment, posture, balance, obstacle avoidance, and joint limitation constraints. Goal-based motion primitives, called synergies, coordinate sets of joint movements which separately attempt to satisfy each of the above constraints. The present methods adapt character movements on-line to accommodate uneven terrain, body modifications, or changes in the environment by automatically transforming and producing joint rotations relative to the instantaneous point of contact of the body with the world. Libraries of pre-configured goal-directed behaviors, such as reaching, sitting, walking, jumping, etc., can be constructed and used to animate a wide variety of characters.

Claims96

Dependent claims

In a method for animating a character figure in a video image memory responsive to an input goal, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, a method for coordinating limb movements subject to at least one constraint of said character figure, said method comprising:

storing a representation of each of said first plurality of joints in said memory;
storing a representation of each of said plurality of links in said memory;
storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
computing, responsive to said input goal, a first set of motions subject to said constraint for each of said first plurality of joints respectively, each motion of said first set of motions being computed for each respective joint independently of the others of said first plurality of joints with said others of said first plurality of joints being held substantially motionless;
modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
rendering said stored representation of said links as the limbs of said character figure in said video image memory.

4 more elements

In a method for animating a character figure in a video image memory responsive to an input goal, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, a method for coordinating limb movements subject to respective first and second constraints of said character figure, said method comprising:

storing a representation of each of said first plurality of joints in said memory;
storing a representation of each of said plurality of links in said memory;
storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
computing, responsive to said input goal, a first set of motions subject to said first constraint for each of said first plurality of joints respectively;
computing, responsive to said input goal, a second set of motions subject to said second constraint for each of said first plurality of joints respectively;
combining said first set of motions with said second set of motions to form a combined set motions;
modifying said stored representation of the positions of said first plurality of joints and said plurality of links in said memory using said combined set of motions;
and
rendering said stored representation of said links as the limbs of said character figure in said video image memory.

6 more elements

In a method for animating a character figure in a video image memory responsive to an input goal, said video image memory depicting an environment in world coordinates, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, a method for coordinating limb movements subject to at least one constraint of said character figure, said method comprising:

storing a representation of each of said first plurality of joints in said memory;
storing a representation of each of said plurality of links in said memory;
storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
selecting an initial joint from said first plurality of joints as a first contact joint;
generating a contact chain from said initial joint selected as said first contact joint, wherein said contact chain indicates the order in which relative transformation matrices are multiplied to determine the location of each of said first plurality of joints in said world coordinates;
computing, responsive to said input goal, a first set of motions subject to said constraint for each of said first plurality of joints;
modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
rendering said stored representation of said links as the limbs of said character figure in said video image memory in said world coordinates.

6 more elements

In a method for animating a character figure in a video image memory responsive to an input goal for coordinating limb movements and subject to the constraint of balance of said character figure, said character figure having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, wherein said links have a respective mass associated therewith and a designated center of mass for said plurality of links, wherein the method comprises:

designating a point in space as a input goal point which is the desired location in space for said designated center of mass for said plurality of links;
storing said representation of each of said first plurality of joints in said memory;
storing said representation of each of said plurality of links in said memory;
storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
computing, responsive to said input goal point, a set of motions subject to said balance constraint for each of said first plurality of joints respectively, such that moving said character figure by said set of motions tends to position said designated center of mass at said goal point;
modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
rendering said stored representation of said links as the limbs of said character figure in said video image memory.

5 more elements

In an apparatus for animating a character figure in a video image memory responsive to an input goal, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, an apparatus for coordinating limb movements subject to at least one constraint of said character figure, said apparatus comprising:

means for storing a representation of each of said first plurality of joints in said memory;
means for storing a representation of each of said plurality of links in said memory;
means for storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
means for computing, responsive to said input goal, a first set of motions subject to said constraint for each of said first plurality of joints respectively, each motion of said first set of motions being computed for each respective joint independently of the others of said first plurality of joints with said others of said first plurality of joints being held substantially motionless;
means for modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
means for rendering said stored representation of said links as the limbs of said character figure in said video image memory.

4 more elements

In an apparatus for animating a character figure in a video image memory responsive to an input goal, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, an apparatus for coordinating limb movements subject to respective first and second constraints of said character figure, said apparatus comprising:

means for storing a representation of each of said first plurality of joints in said memory;
means for storing a representation of each of said plurality of links in said memory;
means for storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
means for computing, responsive to said input goal, a first set of motions subject to said first constraint for each of said first plurality of joints respectively;
means for computing, responsive to said input goal, a second set of motions subject to said second constraint for each of said first plurality of joints respectively;
means for combining said first set of motions with said second set of motions to form a combined set motions;
means for modifying said stored representation of the positions of said first plurality of joints and said plurality of links in said memory using said combined set of motions;
and
means for rendering said stored representation of said links as the limbs of said character figure in said video image memory.

6 more elements

In an apparatus for animating a character figure in a video image memory responsive to an input goal, said video image memory depicting an environment in world coordinates, said character figure being represented in said memory as having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, an apparatus for coordinating limb movements subject to at least one constraint of said character figure, said apparatus comprising:

means for storing a representation of each of said first plurality of joints in said memory;
means for storing a representation of each of said plurality of links in said memory;
means for storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
means for selecting an initial joint from said first plurality of joints as a first contact joint;
means for generating a contact chain from said initial joint selected as said first contact joint, wherein said contact chain indicates the order in which relative transformation matrices are multiplied to determine the location of each of said first plurality of joints in said world coordinates;.
means for computing, responsive to said input goal, a first set of motions subject to said constraint for each of said first plurality of joints;
means for modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
means for rendering said stored representation of said links as the limbs of said character figure in said video image memory in said world coordinates.

6 more elements

In an apparatus for animating a character figure in a video image memory responsive to an input goal for coordinating limb movements and subject to the constraint of balance of said character figure, said character figure having a first plurality of joints and a plurality of links coupled between respective pairs of said first plurality of joints, said plurality of links representing respective limbs of said character figure, wherein said links have a respective mass associated therewith and a designated center of mass for said plurality of links, wherein the apparatus comprises:

means for designating a point in space as a input goal point which is the desired location in space for said designated center of mass for said plurality of links;
means for storing said representation of each of said first plurality of joints in said memory;
means for storing said representation of each of said plurality of links in said memory;
means for storing a representation of the respective positions of said first plurality of joints and said plurality of links in said memory;
means for computing, responsive to said input goal point, a set of motions subject to said balance constraint for each of said first plurality of joints respectively, such that moving said character figure by said set of motions tends to position said designated center of mass at said goal point;
means for modifying said stored representations of the positions of said first plurality of joints and said plurality of links in said memory using said first set of motions;
and
means for rendering said stored representation of said links as the limbs of said character figure in said video image memory.

5 more elements

Dependencies are inferred from the claim text.

Limb coordination system for interactive computer animation of articulated characters

Life of this patent

Limb coordination system for interactive computer animation of articulated characters

Life of this patent

Abstract

Claims96