Custom design question

[#1]

I'm trying to build a DOE with 6 factors, discrete and continuous, the discrete have different levels (mostly 3 and 4 levels). I have 2 questions, 1 of the 6 factors depend on 2 of the other factors (example a distance (xo) depends on the angle (theta) and another distance (yo). I've been messing around with "Define a Constraint" and a lot of googling but still can't figure it out. Any advice? 

Thanks!

[#2]

Can xo be varied independently of theta and yo? Or is there only 1 possible value of xo for a given combination of theta and yo? If xo is determined entirely by the other factors then it is not a factor.