# Feature engineering

I recently realized, that feature engineering (designing input vectors for machine-learning algorithm) is one of the most complicated tasks when applying known algorithms (for example kernel perceptron). My question is: is it okay for scalars in the vector to be of different nature? For example, if your vector is (width, height, length) that seems okay to me, because all these three parameters are of the same nature and it's really logical to be there together. I know, all these terms are very intuitive (as is my concern) but I hope I elaborated enough.

In my example, there are mixed features, for example: whether or not A action was performed, was action B performed after action C or not, to what extent was action D performed etc...