SMath fails to compute the cross product of two vectors, if one of them (or possibly both) is a product with a symbolic constant and a vector (a scaled vector).
SMath complains that the vector product is only defined for three-element vectors.
This is particularly nasty, as this applies also to vectors normalized by division by their length.

Martin Kraska
Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx