# Network arch bridge - how to model radial hanger

In the radial hanger arrangement the distances between the upper hanger nodes and the angle between hangers and arch remain constant. How can this be done in grasshopper?

Something like this?

Arch Bridge_00.gh (9.8 KB)

Offset (Outer) moves the start point from the outer arch. Odd and Even hangers are offset into opposite directions. āInnerā offset does the same but involves the lower end of the hangers. The angle (hanger-hanger/2) is published in one output. The geometry can be baked and the lower end of the hangers trimmed along the road. If you set the āinner radiusā to zero, the lower end of the hangers will attach to a straight line going through the center (this may give strange results though, and the angle distribution about the arch will not remain constant).

// Rolf

4 Likes

Hi Bjorn, in case you want to use standard GH components, see the attached solution. Divide an arc into segments based on length, then using a combination of ādispatchā and āweaveā to angle every second hanger.
Only uses a dozen standard components, so probably quicker to create than the 200 or so lines of code used by Rolf (although it is a very nice script! )
Cheers,
Steven
171221 Bridge Hangers.gh (11.7 KB)

1 Like

nice one.

consider swapping the DivideLength component for DivideCurve.
(depending on what youāre after)

Hahaā¦ I was actually coding an entirely different component when I read this post, and realized that I could easily adapt it to this problem by criss-crossing some āspokesā andā¦

I could have cleaned up the code some more though, like the data trees and stuff, but a quickie is typically a quickieā¦

I cleaned up and modified the code a little bit in order to make the horizontal line a bit more interesting to play with. Set the inner radius to zero (0) to activate the horiz line. Then play around with Elevate (rising the horiz bar above the circle center, as pictured) and the inner hanger offset.

I have no idea how useful it is, but I found it amusing nevertheless.

Arch Bridge_03.gh (11.2 KB)

// Rolf

1 Like

Thanks! This scripts works nearly perfect. But the rotation of the hangers should be according to the tangent in each point. Now itās according to vertikal direction. I has included divide curve in the revised script. But how can I modife the rotation so it is according to the tangent in each point?
171221 Bridge Hangers.gh (12.4 KB)