Development tools for animated character rigging

1. A computerized method for transferring an expression from a plurality of source rigs characterizing a plurality of animated characters to a target rig characterizing a target animated character, each of the source rigs and the target rig characterized by a set of joints and a skin mesh having a plurality of vertices, each vertex, in turn, characterized by a matrix of weights relating a response of the vertex to movement of associated joints, the method comprising:

a. defining neutral and goal expressions for each of the multiplicity plurality of source rigs relative to a neutral expression of each source rig;

b. building a mathematical model mapping neutral shape to goal expression offsets on a basis of the neutral and goal expressions defined for the plurality of source rigs;

c. applying the mathematical model to an unseen neutral expression shape to calculate required expression offsets; and

d. vectorially adding the calculated set of offsets to a neutral expression of the target rig in such a manner as to implement the goal expression on the target rig, thereby transforming the target rig;

e. transferring a set of skin weights between a selected source rig of the plurality of source rigs and the target rig, the target rig characterized by an associated target skin;

f. mapping joints of the target rig to joints of the selected source rig of the plurality of source rigs by means of a transform function derived on the basis of interpolation;

g. transforming vertices of the associated target skin by means of the said transform function thereby deriving a plurality of transformed target vertices;

h. identifying a plurality of source skin polygons intersecting a normal to a specified transformed target vertex;

i. choosing a source skin polygon to associate with each transformed target vertex; and

j. identifying each transformed target vertex with the intersection of a normal to said transformed target vertex with the chosen source skin polygon.

2. A non-transitory computer readable medium for storing an expression from a plurality of source rigs characterizing a plurality of animated characters to a target rig characterizing a target animated character, each of the source rigs and the target rig characterized by a set of joints and a skin mesh having a plurality of vertices, with each vertex, in turn, characterized by a matrix of weights relating a response of the vertex to movement of associated joints, the non-transitory computer readable medium having computer readable program code thereon, the computer readable program code comprising:

a. a computer code module for defining neutral and goal expressions for each of the plurality of source rigs relative to a neutral expression of each source rig;

b. a computer code module for building a mathematical model mapping neutral shape to goal expression offsets;

c. a computer code module for applying the mathematical model to an unseen neutral expression shape to calculate required expression offsets; and

d. a computer code module for vectorially adding the calculated set of offsets to a neutral expression of the target rig in such a manner as to implement the goal expression on the target rig, thereby transforming the target rig;

e. a computer code module for transferring a set of skin weights between a single source rig and the target rig, the target rig characterized by an associated target skin;

f. a computer code module for mapping joints of the target rig to joints of the single source rig by means of a transform function derived on the basis of interpolation;

g. a computer code module for transforming vertices of the target skin by means of the said transform function thereby deriving a plurality of transformed target vertices;

h. a computer code module for identifying a plurality of source skin polygons intersecting a normal to a specified transformed target vertex;

i. a computer code module for choosing a source skin polygon to associate with each transformed target vertex; and

j. a computer code module for identifying each transformed target vertex with the intersection of a normal to said transformed target vertex with the chosen source skin polygon.