I have two hyperboloids and the curve of their intersection (this can be an ellipse or hyperbola). How can I get an equation of that curve projected onto the plane the curve is placed? I am able to find a projection onto one of the basis planes (OXY, OXZ, OYZ) but a can't understand the right way how to do it with an ordinary plane. Finally, according the pictures I need to find parameters of the red curve of intersection.