# Twist in curve / parabola

Hello world!
I tried using spiral but couldnt flip two circle as in image.
how to control the twist with points?

twist_2023Aug19a.gh (11.3 KB)

P.S. Oops, that was four curves - this is two:

twist_2023Aug19aa.gh (18.3 KB)

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Playing with code like this can be instructive. The BiArc curves I used have an āRā (Ratio) input so I added a slider (0 to 1) for that. When set to zero, the āAngleā slider becomes useless.

I changed the range of the āAngleā slider from ā0 To Piā to ā-Pi To +Piā, which means that to work correctly, the end tangent vectors (āTeā) from the white circle must be reversed. So I added an Eval component to do that. Then I started playing with MultiPipe (MS), which I donāt know much about.

I wanted to set āNodeSizeā radii for both ends (the same) and the the midpoint at the top (larger), so added two sliders for those values. Playing around, I saw some weird flaws so added a āCountā slider and Graph Mapper to see if more than three āNodeSizeā values made any difference.

twist_2023Aug19b.gh (29.4 KB)

It looked like some of the issues were with BiArc so I replaced it with Arc SED, which has a start tangent vector (āDā input) but no end tangent vector, only an endpoint. It behaves differently, so doesnāt match the goal image you posted. But itās nice in a different way.

twist_2023Aug19c.gh (28.4 KB)

Very interesting.
Oh, in both models, flattening the āCurvesā input to MultiPipe has a very peculiar effect

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Thanks Joseph, your last GH file above really got my attention and I knew I had to turn it into something unique that I could print. It didnāt take very long before I came up with this:

This is my slicerās sliced view - the GH produces a Closed Brep so there are no errors in the exported STL file. Even though it slices OK itās got some areas that are too thin, so Iāve got a bit more work to do on it. Consequently I canāt predict yet what the end result will look like.

Five ribs instead of four? Without your GH code, I canāt tell which version you used (ābā or ācā?) or if you flattened the āCurvesā input to MultiPipe? If you did flatten, be aware that the result is two different breps (SubDs) that intersect each other. Iād like to understand MultiPipe better

Iāll post the final result - hopefully later today. I used only one curve from c, Lofted it, scaled that, used edges for Ruled surfaces, joined all together, then made 5 item Polar array. I like using prime numbers for geometric arrangements.

So you didnāt use MultiPipe at all? Weird looking thingā¦ With all the parameters I provided, why would you scale it?

The Loft surface looked nice - fairly unusual for sure. But it needed thickness. Offset didnāt work because of all the curvature; scaling worked better. The whole thing is quite small so I doubled itās size in the slicer. Iāll put that back into the GH file along with some other stuff I think will produce something useful.

Fun isnāt it? What happened to @super_mario ?

twist_2023Aug20a.gh (29.5 KB)

SUnion is quite slow and fails sometimes so it is disabled.
Wish I understood MultiPipe better.

P.S. This is why SUnion is slow - that busy center is a confluence of round āCapsā from MP.

Hi, Joseph
Iām incorporating youāre script with an rectangular base rather than original circle, so that extended curve can rest on rectangular base and can act as tensegrity stc.
Iām new here but yes I love it here.
Thank you Joseph and all.
And wondering to use kangaroo to check it as tensile stc

Until you post your code, I wonāt know what you did but did it occur to you that you can have multiple inputs, like this?

twist_2023Aug20b.gh (13.9 KB)

Uh-huhā¦ Until you post some code, you are likely to be ignored. After you get the support hoops the way you want, you might need a separate thread for Kangaroo and the mesh fabric surface.

Hereās my version 0.8:

I donāt like this enough to print it, but it is Closed Breps and will print OK. The GH file is āunnamedā because it doesnāt seem like itās quite finished yet. When it is Iāll put an LED puck light inside and it can be a table lamp or something like that.

unnamed.gh (24.2 KB)

TWIST.gh (15.3 KB)

I tried to collect point as in the image. Plan is to rest the curve end point at the desired points along the rectangle boundary.

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Sorry about that - Iāve been using the trial Rhino 8. You should be able to replace it with the Rhino7 Midpoint component with no problem.

Yeah, I already did that. Rhino 8 isnāt the problem, itās Wombat.

I see no resemblance at all to my code.

The slider connected to āRatioā should be 0 to 1 with default of 0.5

Yeah - I donāt know how Wombat got installed. Iāve also got Heteroptera - whatever that is.

After numerous iterations the only parts of your code left are the initial ones that establish the planes for the Loft control curves. I still canāt quite visualize how that works.

Your change from a base circle to a rectangle has several problems. I fixed some of them.

TWIST_SM_2023Aug20a.gh (13.4 KB)

You could use the base circle and make a square from the points, like this:

twist_2023Aug20c.gh (13.2 KB)

If you insist on a rectangle, youāll have to figure it all out. Starting position is different from a circle, you probably want the Discontinuity points (corners) instead of Divide Curve.