# Rotating bounding boxes along a curve

Hi, I’m really new to Rhino and Grasshopper, so my problem is most likely a very simple one, but what is going on essentially is that I’m creating a simple outdoor bench, and I wanted to use the vertical lines seen in the image to make square supports for the back part of the bench. My problem is that i can’t figure out how to extrude them in such a way to have each of them be parallel to the seat.
The most promising thing I’ve tried is forming a pipe out of each line, then creating a bounding box for each pipe, and selecting the same lines as the plane for the bounding boxes. This seems to vertically incline the boxes to the angle i want them to, but they’re still all rotated to the x and y axes, and not parallel to the seat. So I guess if you can tell me how I can rotate the boxes around the seat, the problem would be solved too.
Attached images show the lines im trying to use, and the bounding boxes (with a top view showing how they’re not aligned with the curved bench)

Hello. Assuming that you have one curve as input, you can get “horizontal frames” of that curve. These frames are aligned to the direction of the curve, so just use “deconstruct plane” to get anything that you need - vectors and origin. The rest is extruding of base rectangle along some tilted direction.

Hi,

This is how I would go about solving it:

1. Use surface closest point on the back surface of the bench, and feed in the points from where you are generating the centreline for the box section.
2. Use evaluate surface and plug in the UV coordinates from surface cp. This will give you the relevant normal to the surface at that exact point.
3. Use this normal to generate your desired profile

With this method, your boxes will always be perpendicular to the surface, even if you change it

Hi! thank you both for the responses. ultimately I tried with the method of Adwait and after aligning the frames i got exactly the result I was after. Thank you very much!
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