Element index vector, specified as a vector of positive integers each of which takes
a value from 1 to N. The quantity N is the number
of elements of the array.
Positions of array elements, returned as a 3-by-M real matrix.
Each column of pos defines the position of an element in the local
coordinate system, using the form [x;y;z]. If the input argument
elemidx is not specified, M is the number of
elements of the array, N. If elemidx is
specified, M is the dimension of elemidx. Units
are in meters