Whether you are building a HumanIK character from scratch or planning to use an existing skeleton or mesh, you can use Maya's HumanIK tools to set up your character.
A HumanIK character must have a valid skeleton definition that maps out its skeletal structure. You can create a skeleton definition using the Skeleton tab in the Character Controls window. This step is required to ensure your character's skeleton is understood by the HumanIK solver.