Lofting Trapezoid to Rectangle with Planar Surface

I have a given trapezoid that I need to loft to a rectangle with planar surfaces. The trapezoid is roughly 1.5m above the rectangle and the total area of the rectangle is 10m2 while the trapezoid is smaller and must remain inside the rectangle in plan view… Obviously the trapizoid can rotate on any axis but the rectangle must be level. I can get close just rotating the trapezoid, but it is not exact. Anyone have any ideas?
Trapizoid to Rectangle.3dm (24.4 KB)

Yes, but you didn’t post your file.

3. Attach minimal versions of all the relevant files


It works for me after internalizing your 2 figures into GH. Am I missing something?


The surfaces need to be planar. If you just took what I posted then they are probably not planar. Close but not exactly.

You are correct - I missed that requirement. Does this work for you? There’s probably a simpler way to do it, but this is what first occurred to me. (9.4 KB)

Yea I need the sides planar. The top curve does not need to be level.

this gives you a planar solid that approximates the top trapezoid, given the constraint that it needs to end exactly as the bottom rectangle: (13.6 KB)

it works by creating a plane given a line (from each bottom rectangle edge) and a point (along the corresponding trapezoid edge)

you can add more control by -for instance- dedicated sliders for each edge: (15.4 KB)

So its not exactly what I needed but it got me there with some tweaking. Thanks so much. I was struggling for some reason where to start and this got me on track.

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