# Lunchbox Triangular surface

**URL:** <https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749>\
**Category:** Grasshopper\
**Tags:** lunchbox\
**Created:** [April 23, 2020, 4:30pm UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749 "2020-04-23T16:30:19Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![blomberp](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/blomberp/32/150637_2.png) [@blomberp](https://discourse.mcneel.com/u/blomberp)\
**Post date:** [April 23, 2020, 4:30pm UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749/1 "2020-04-23T16:30:19Z")

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Hello, so I’m a second year in architecture school in the UK. and I got this project where I’ve designed this triangular roof, with surfaces because in the beginning, it was a bit too fluid to make it work, so I triangulated the whole roof, making it into triangular surfaces. but now I’m trying to make a spaceframe or a truss system to support the roof and for this, I’ve found the truss system in Lunchbox, but instead of going with the Triangular surface I got, it makes it into a 4 point surface, basically extending it or mirroring the surface.

And I am by no means a pro or even an intermediate at grasshopper so if this isn’t really gonna be viable then if anyone has a different way of doing it or a better way id love to be pointed in the right direction!

 ![Canvas at 17;07;32](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/4/a/4a4c9ab6dd8db0c6789c5a7065227e20edc3b7ad.png) ![Canvas at 17;07;3221](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/e/5/e508278ae94299cafdacb84062348fa5099ea087.png)

Kind Regards Blomberp

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**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [April 23, 2020, 6:08pm UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749/2 "2020-04-23T18:08:01Z")

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Are you after a truss “like” this? (Note: in this example quads are converted to triangles)

[Mesh\_ToTruss\_StaticDemo\_45A.3dm](https://discourse.mcneel.com/uploads/short-url/A69CGDEOAAhKfXXD6tfycDZBD8M.3dm) (1.1 MB)

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<div class="post-metadata">

**Author:** ![blomberp](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/blomberp/32/150637_2.png) [@blomberp](https://discourse.mcneel.com/u/blomberp)\
**Post date:** [April 23, 2020, 6:20pm UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749/3 "2020-04-23T18:20:57Z")

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Essentially yes

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<div class="post-metadata">

**Author:** ![PeterFotiadis](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/peterfotiadis/32/472316_2.png) [@PeterFotiadis](https://discourse.mcneel.com/u/PeterFotiadis)\
**Post date:** [April 24, 2020, 6:03am UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749/4 "2020-04-24T06:03:16Z")

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I can provide an **entry level** solution on that matter (i.e. without the orthodox connectivity trees that correlate the classic 2 truss Lists [base-top node points]) but it would be purely via code (C#). Note that since you should always check the mesh for islands (i.e. disjoined pieces) … in fact we are talking mesh Lists (and connectivity trees with **higher** dimentions that 1).

Notify if you want such an approach.

That said the **general case** of this (i.e. random trusses PLUS the required members of the corresponding envelope) is by far the most challenging parametric task mostly due to **clash checks** between the struts (and/or the fixing bolts) on a per node basis. Fixing potential issues like these **on the fly** is 100% impossible without code.

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<div class="post-metadata">

**Author:** ![Michael\_Pryor](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/michael_pryor/32/489117_2.png) [@Michael\_Pryor](https://discourse.mcneel.com/u/Michael_Pryor)\
**Post date:** [April 24, 2020, 9:35am UTC](https://discourse.mcneel.com/t/lunchbox-triangular-surface/100749/5 "2020-04-24T09:35:53Z")

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See these threads. What you are dealing with is are trimmed surfaces. Trimmed surfaces are almost always evaluated by their untrimmed underlying Nurbs(4 point) surface, it is how Nurbs works. This isnt a Grasshopper knowledge issue, it is a Rhino knowledge issue. Check this: [https://www.rhino3d.com/download/rhino/5.0/Rhino5Level2Training/](https://www.rhino3d.com/download/rhino/5.0/Rhino5Level2Training/)

> **[Split and trim commands | Rhino 3-D modeling](http://docs.mcneel.com/rhino/5/help/en-us/seealso/sak_splittrim.htm)**
>
> Split and trim objects with other objects.

> **[Rhino - Search Results](https://www.rhino3d.com/searchresults/?q=forum%20topics%20trimmed%20versus%20untrimmed%20surfaces)**

> [@Untrimmed control points on new surface](https://discourse.mcneel.com/t/untrimmed-control-points-on-new-surface/100695):
>
> I created this surface by playing with control points. But when I try a space truss frame or any structure in the grasshopper, it moves outside, it doesn’t define my new surface. What should I do to work on the surface I just created? Please help…Thanks for now. [problem2.3dm](https://discourse.mcneel.com/uploads/short-url/4f7uShfBPqVSrLRlKgV47gZyQih.3dm) (339.7 KB)

> [@Paneling Polysurfaces of Trimmed faces](https://discourse.mcneel.com/t/paneling-polysurfaces-of-trimmed-faces/92308):
>
> I got the following question from user, and I will post the answer below since this is rather common question. "I boolean unioned spheres together on rhino and then used paneling tools on them to create a structure. However, the paneling tools creates a grid for the entirety of each sphere, as if it remembers each of the spheres before i unioned them together. Do you know how I can get it to panel only what I unioned together? Sincerely, a confused user of Rhino"

> [@Creating a Brep or surface from curves on Rhino or GH](https://discourse.mcneel.com/t/creating-a-brep-or-surface-from-curves-on-rhino-or-gh/100411/13):
>
> I similar answered this 2 days ago… But instead of saying that he did not understand he simply opened a second thread and started asking the similar question again and again. He refuses to accept that there is no good solution with isotrim. There is absolutely no point in changing the surface to be untrimmed just for paneling issues. In order to help, people actually need to know what he is planning to do otherwise its a waste of time…

> [@Map Grid to Curved Surface](https://discourse.mcneel.com/t/map-grid-to-curved-surface/100264):
>
> Hi all, I have created a hexagonal grid with attractor points that I would like to attach to a curved lofted surface. I have tried everything but I can’t seem to map the hexagons onto my surface. Is there any fix to this? I can’t use plugins for this assignment. Any help is greatly appreciated, thank you! [Hexagon Grid.gh](https://discourse.mcneel.com/uploads/short-url/c3RXVabQGmZcvs33N8vsif6dU2Z.gh) (27.0 KB)

> [@Re-Creating a trimmed surface for Lunchbox paneling](https://discourse.mcneel.com/t/re-creating-a-trimmed-surface-for-lunchbox-paneling/73366/2):
>
> [SRF.gh](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/5/8/581bfee7cced0a1f3b20493df117e34278d37c53.gh) (63.2 KB) Have a look at the attached. From my knowledge I can only try to approximate the original surface as close as possible, but never identical. You can adjust the tolerance by playing with the slider, and also the original number of contour curves.

> [@(Lunch box) triangle surface and structure on a curved surface](https://discourse.mcneel.com/t/lunch-box-triangle-surface-and-structure-on-a-curved-surface/82813):
>
> Hi. Does any body know how to create a triangle panel structure on a curved surface? I have tried this tutorial ([https://www.youtube.com/watch?v=fjFFoE7ZIS0](https://www.youtube.com/watch?v=fjFFoE7ZIS0)) but it does not work \<-- This kind of structure. Here is what I have so far: [DIAGRID HELP.3dm](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/4/8/48060cc05fb1220c41469a9120a0f87db7628163.3dm) (224.8 KB) [LUNCHBOX GRID.gh](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/c/c/cc8de2a0563953a42160f3f085d4c2492e5d2244.gh) (5.0 KB) ![2|690x452](upload://izQ2q5fVpjL9nzDdaSXqrmLgVlC.jpeg)

> [@Grasshopper (or Rhino) referencing original surface - not the split one](https://discourse.mcneel.com/t/grasshopper-or-rhino-referencing-original-surface-not-the-split-one/100183):
>
> Hi guys, To keep it simple: I made a geometry in rhino and the applied a 3D voronoi, manipulated it, scaled them down and then baked the results. I now want to panel the surfaces of those shapes (either with lunchbox or by using domains and divide surfaces) but each way I do it, grasshopper wants to reference the original much larger surface. Is there a way around this? I have tried evaluating the surface - to no avail and curiously, when I apply divide surface, it’s gets it ok… but the domai…

> [@Understanding trimmed surfaces](https://discourse.mcneel.com/t/understanding-trimmed-surfaces/29930):
>
> Is there a tutorial or good concise explanation about the differences between trimmed and untrimmed surfaces and when/if you need to shrink trimmed surfaces? Thanks, Dennis