I've been scratching my head over this one. I'm trying to find a system of equations to solve for points R and S. The known parameters are: Point Q, tangent vector t and the axis vector a. The following vectors are perpendicular to each other: a,d a,b b,c c,t d,t The other known parameter is that vector c has a magnitude of 0.0625. This creates a quadrilateral that is skew, with vector c and a being at an angle to each other and pulling the sides out of plane. I'm trying to find the mathematical way of solving this across a number of points. SolidWorks can find one valid answer for the sample (and fully defines the topology) but I cannot get a system of equations to solve to match in Mathcad. Any method would be appreciated? I'm trying to get it so that I don't have to rely on the SolidWorks sketch engine to reduce computation times.