I want to create a surface that uses a profile of a picture frame molding. But the rail is not a straight line (or even a simple curve). The rail has a shape like a sine wave. What the result will be is a picture frame molding that has a typical cross section of a molding one would use for a picture frame. But, the difference is that there is a ‘ripple’ pattern along the length of the molding.
My problem is that the cross section profile rotates forward and backward along the path of the rail to keep it perpendicular to the rail at each point. However, what I want instead is for the profile to stay perfectly vertical. That is, it should shift up and down as it follows the rail rather than rotating to stay perpendicular to it. If the profile is drawn on the Y-Z plane and the rail is drawn on the X-Z plane, then the profile at each point in the X direction should always be perpendicular to the X axis (staying parallel to the Y-Z plane).
I don’t see any way to do this in Rhino. Any suggestions I might try?