The new named item is assumed to weight 1.0.
void weightarrayblend(string &names[], float &weights[], string newname, float blend)
Blends the existing arrays with the new item using the specified blend value.
void weightarrayblend(string &names[], float &weights[], string newnames[], float newweights[], float blend)
Blends the existing arrays with another using the specified blend value. The result has the union of items in each input array.