Curved diagrid

Grasshopper
1

Hello All,
I apologize in advance if my question is silly.
I have been working on a diagrid structure on a curved surface, but since the Lunchbox Tool provides straight lines, i had to use flow along surface.
Now I am trying to add 60x60 sized members on these curved lines, but the joinery and members are very unorganized.
Also, is there a way I can get the joinery details of each member as they are probably going to be welded together.
Please find attached the files and pic.for forum.3dm (180.3 KB) for forum.gh (35.7 KB)

Annotation 2020-08-06 120451
Annotation 2020-08-06 1204511613×646 80.5 KB

2

Hi Bhavyarishi,

Not a silly question at all. One thing to mention first up though is that because of the nature of your shape, there is a trade-off in terms of member fabrication and connection simplicity:

  1. Doubly curved members which results in a neat welded connection.
  2. Members made out of singly curved faces (but still bent in two directions) resulting in a ‘quite’ (technical term) neat connection to resolve.
  3. You keep the members completely singly curved but have a more difficult joints to resolve.

diagrid1
diagrid11638×494 68.7 KB

The attached definition contains all of these options. The elements are centred on the member lines for this example and I estimated your extruded ellipse surface to be able to get some alignment vectors for the member sections. The singly curved elements (option 3) are converted to arcs.

diagridGraph
diagridGraph1571×636 52.1 KB

diagrid2
diagrid2710×689 121 KB

I hope this aids your understanding of the trade-offs. Note that for certain surfaces/curves you can have single curvature and a simple connection, for example isocurves around a torus.

Best,
John.

for forum_edit.gh (45.6 KB)

1 Like
3

Thank you so much John!
I think this solved my problem and I definitely understood it better.
Now, I’ll have to talk to my fabricators whether they’ll be able to pull off a doubly curved member!
Thank you nonetheless!
Extremely helpful this was.

4

Thanks, no problem at all. It’s no coincidence that many of of these diagrid structures are made from timber, as the torsion can usually be accommodated. Maybe the steel can be cold bent in your application, it’s quite a gradual change, but lots of factors involved in knowing whether it’s possible.

Take care,
John.