Unroll Ruled Surfaces in Grasshopper


Prompted by a request on the Grasshopper3d.com message board, I set out to make a definition for unrolling ruled surfaces in GH. I’m not the first to attempt it – see the work of Chris Chalmers here: http://biosarch.wordpress.com/2009/09/23/unrolling-surfaces-in-grasshopper/ – but I think my approach may be a bit more streamlined and flexible.

I make no promises about its accuracy, but the result seems to work fairly well, with results comparable to those produced by the “unroll” command in Rhino – however mine tends to produce smaller areas, whereas the Rhino one always seems to tend larger. It will not work on double-curved surfaces! Feedback, real-world fabrication test results, and suggestions for improvement welcome!

The definition and an example Rhino file are available here:
Rhino File

10 Responses to “Unroll Ruled Surfaces in Grasshopper”

  1. 1 Konstantin

    Nice to see new Grasshopper modules, I really love this plugin. May be I soon share some too.

  2. 2 carrie

    do you have the grasshopper file for download? clicking the link sends me to a page of code. i would love to look at your definition. i am attempting to unroll some panels across a surface.

    • 3 heumanndesigntech

      Hi Carrie –

      That page of code is the grasshopper file. Simply right-click and save the .ghx file to disk.

  3. Hi Andrew,

    Would I be able to upload this one to parametric model as well?


  4. 6 Bridgette


    I’m interested in using your unroll command. I’m new to grasshopper but have built a panel of extruded surfaces. I want to plug my ghx formula into this unroll formula. Is that possible?

  5. 7 heumanndesigntech

    Hi Bridgette – What you describe should be possible. I can’t give you more specific detail without knowing more about your own definition.

    I also want to point you toward an option that might be a bit simpler and more streamlined. If you have Rhino 5.0 (with a rhino 4.0 license you can install the beta version for free) you can use the python script component and Steve Baer’s unroll script, which exactly mimics the Rhino UnrollSrf command. This script is available for download here: http://www.grasshopper3d.com/forum/topics/unroll-unfold

    You might also try Marc Hopperman’s older vb script, available here. http://www.grasshopper3d.com/forum/topics/when-comes-the-unrollsrf?commentId=2985220%3AComment%3A20884

    Hope that helps!

  1. 1 fabrication resources! « coda·
  2. 2 UnRolling | Parametric Wood

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