Sweeping a section along a Spiral and orient it always inwards

Grasshopper
1

Hi, can anyone help on this please. Trying to sweep a rectangular profile along spiral curve, but orientation should be in a way that the long side of the rectangle always faces the inside of the c/l of the spiral.

Like lachlan’s bridge in aus (Lachlan's Line Bridge Project - Summary, Articles, Photos & Videos | This Is Construction)

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Its a full spiral bridge

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but rectangular section always orients in towards the center of the helix

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I am trying to achieve similar for these curves with rectangular section,

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this is my attempt using sweep1 but it doesn’t quite work the way i want it to,

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Files attached,
Spirals and longitudinals.gh (18.8 KB)
Spirals and longitudinals.3dm (77.4 KB)

Thanks for helping in advance.

2

Vikas Venkatesha,
Use Perp Frames (aligned) along your curve. Use the orient component to move a crossection of your shape to those frames, then Loft instead of sweep. I believe this will get the results you are looking for.

Bill