CS777 Project 1 Developing Maya Plug-ins for motion related projects Kyungsuk David Lee

Objectives  Simplify the process in doing various motion related research  Understand Maya’s architecture  Create custom objects and commands that do what we want  Modify custom object attributes using Maya’s user interface  Get interactive response from Maya

Types of Maya Plug-ins  Command Plug-ins Temporary objects Undo/Redo easily ex> group –empty –name UW –parent Wisc  Dependency Graph Plug-ins Creates a node that stays in the scene Need to a mechanism to respond to changes in the environment ex> TransformNode

DAG Hierarchy (Directed Acyclic Graph)  2 Types of nodes  Transform Nodes  Shape Nodes  DAGPath is needed to specify an object that is instanced example) |Transform1|Transform3|Leaf  Object names can be reused as long as the same name does not appear on more than one DAG node with a common parent

Using Hypergraph to see DAG Hierarchy

Dependency Graph Nodes  Stays in the scene and affects each other  DAGNodes are also a type of Dependency Graph Node  Does not have to be acyclic  Uses plugs to communicate with each other

DG Node Attributes & Plugs  Each node can contain static and dynamic attributes  Plugs are used to connect the attributes that affect another  Does not have to be acyclic between nodes  Shouldn’t have cycles in the graph of affected attributes  Push and Pull system to update the effect of changes

Using Hypergraph to see Dependency Graph

LoadBVH & LoadPlants Command  Implemented in MEL  Loads a BVH file into Maya  Loads foot plant information from a file that is in a specific format  We don’t need to use BVH files but the structure of a skeleton should be in UberSkeleton format for use with FootSkateSolver

FootSkateSolve Command  Takes the currently selected DAGNode and if it has the proper hierarchy, does foot skate solving in ways described in Lucas Kovar’s paper.  Limb stretches are done by joint scaling  Commands can be easier to implement in MEL (Maya Embedded Language)

FootPlantLocator DG Node  A Locator Node is a transform DAGNode that visualizes our custom object in ways we like  Locator Nodes are not renderable  Can be transformed using Maya’s UI ex> FootSkatePlant, Camera

FootSkateSolverNode  A Dependency Graph Node that stores the original motion and could possibly do interactive FootSkateSolving interactively  Connects the translate attributes of all the FootPlantLocators to its internal attributes by using plugs