The Spline Toolbox provides default knot sequences for use when it is difficult to choose a knot sequence for your data. The Spline Toolbox also includes a command for improving a given knot sequence. The B-form is particularly useful during the construction of a spline. All splines can be represented in both ppform and B-form for both univariate and multivariate functions. This means that the functions for constructing spline approximations can deal with gridded data in any number of dimensions.
Most functions also support tensor-product splines in any number of variables.
Thus, the data being fitted can be vector-valued and even multivariate for creating curves or multidimensional surfaces.