|Mesh mesh||The Mesh for the subset, may not be null.|
|Material material||The Material for the subset, may not be null.|
|Matrix& transform||A transform Matrix representing the Mesh’s location relative to the origin of the Model.|
|RETURNS: int||The index of the subset that was just added.|
Adds a new subset to the Model, and recalculates the bounds.
model.AddSubset( Mesh .GenerateSphere(1), Default.Material, Matrix .T(0,1,0));