Can I choose how a box unrolls in Grasshopper?

Grasshopper
1

If I draw a box in grasshopper and remove the bottom surface, how do I unroll this open box so the top surface is in the middle and the sides fold up on the four sides of the top surface?

Thanks in advance.

2

Sorry I didn’t read properly
 In Rhino, you could try the command _UnjoinEdge

1 Like
3

Perfectly reasonable question, where is your GH file? What component are you using to unroll? This Unroll component is from OpenNest.

unroll_box_2024Aug30a
unroll_box_2024Aug30a1748×683 130 KB

Adding Jitter tells me that the sequence of surfaces affects Unroll.

unroll_box_2024Aug30a2
unroll_box_2024Aug30a21618×748 136 KB

P.S. @martinsiegrist’s cryptic reply is the key. In Rhino, ‘_UnjoinEdge’ and select the vertical edges, then ‘UnrollSrf’ and toggle the option ‘Explode=No’. Wonder if OpenNest Unroll works the same way?

unroll_box_2024Aug30a3
unroll_box_2024Aug30a3783×605 61.2 KB

1 Like
4

I forgot I have a definition with scripts for both unjoin and unroll. The scripts are by @DavidRutten and @Michael_Pryor

{101D6B22-207E-450B-A6D0-1FB6844E1965}
{101D6B22-207E-450B-A6D0-1FB6844E1965}2439×774 150 KB

{A0734513-EC84-4A63-B142-DC1F46214552}
{A0734513-EC84-4A63-B142-DC1F46214552}2227×1184 106 KB

brep_unjoin_edge_unroll_c.gh (23.8 KB)

5

R8 C#. The first script (U = B.UnjoinEdges(edges);) is rather slow and depends on edge midpoints that are not otherwise defined/derived. The second script has a ‘C’ input with two weird curves that make no sense at all :interrobang:

On the other hand, for the specific case cited in this thread, the four sides can be rotated by their top edges.

unroll_box_2024Aug30b
unroll_box_2024Aug30b1790×448 136 KB

unroll_box_2024Aug30b2
unroll_box_2024Aug30b2703×436 14.2 KB

unroll_box_2024Aug30b.gh (15.2 KB)

6

I should have deleted the curves
 Thos are frrom another example. Curves and points can be unrolledd with the polysurface.

The points are needed to define which edge is unjoined.

7

I left a “Persian flaw” in my code - rotation direction (±) depends on the direction of the axis edge curves. :roll_eyes:

Persian flaws are considered a desirable feature of Persian rugs and are often seen as a sign of quality and authenticity. The idea behind the Persian flaw is that perfection is only in the hands of the gods, and that even the most skilled craftsmen should not try to claim it.

2 Likes
8

Thanks already for helping me out here. I’m rather new to grasshopper and experimenting for my employer to speed up design.
This is the file I started with but got stuck.
What I see above looks very promissing.
Thank you guys.
Pallet cover Parametric.gh (10.1 KB)

9

Way too late :bangbang:

missing
missing613×226 8.11 KB

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10

Plugins.

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11

Your “box” isn’t a box, it’s five separate sides. Cyan group fixes that. Scale of your box and my two examples are vastly different! You have to zoom way in on the origin to see mine.

unroll_box_2024Aug30c
unroll_box_2024Aug30c1916×681 123 KB

unroll_box_2024Aug30c.gh (23.9 KB)

Added purple box at the bottom to “flip rotation axis” but QA testing is minimal.

1 Like
12

Thank you very much for your help.
I am going to try it out.