How control the bottom side with the Flow along surface

Hi all,
I had other 3D experience that can use two face to morph the 3D without deform the bottom side, as the image.

I try to use the flow along surface, but I can not control the bottom side.
Could help me to solve this question, thanks

Hello- I am not sure what this means - do you want he face that is away from the target surface to remain flat and the face that is on the target surface to take the shape of that surface?


Sorry for the confuses. I explain in more detail as describe below,

Hello- from your image, it looks like a case in Rhino where you would simply trim or BooleanDifference the top, curved surface from all of the smaller parts - and not use FlowAlongSrf at all. Can you post an example?


Thank you for your reply. There is a boss on the smaller parts.
I don’t think that using simply trim or BooleanDifference the top can get the final shape I want .

Please find the attachment .
flow_along_surface_test.3dm (1.4 MB)

Hello- you can do this my flowing cage conrol points - it seems a little messy but it works.

flow_along_surface_testMaybe.3dm (294.9 KB)
Note you need to set ConstrainNormal=Yes.


I’m grateful for your assistance.