Sporph & Flow along surface

Hi guys, I find out that the ‘Sporph’ component in Grasshopper has the same function as the ‘flow along surface’ in Rhino when ‘ConstrainNnormal’ option is NO.

So I have a question: how can I achieve the function in Grasshopper when the ‘ConstrainNormal’ option of ‘flow along surface’ is Yes? Just like the picture below:

Map only the bottom faces of the boxes onto the curved surface and extrude these along the z-axis.

Yes yes, for these boxes this way works. But when these are complicated things like car’s grill, this way can’t work . What I mean is that in Rhino there is an option which can change the result. I think there should also be an option in Sporph which can be added lately.