Flatten (unroll or squish) an imported (joined surface) part?

I have imported a .step file into Rhino which I want to flatten.

I have achieved this partially with the “unroll” command, but it splits the part up into its individual surface components.

That might be expected, but what I did not expect was the “squish” command to do the same.

Is there a way to flatten a joined surface object without splitting it up into its individual surfaces?

In the unroll srf command, change Explode to No
Select curves on polysurface to unroll ( Explode=Yes Labels=No KeepProperties=No ): Explode=No

Thank you!

So that improved results somewhat but I’m still uncertain about one thing:

Rhino asks me to “select curves on polysurface to unroll” and I can click on the surface, but no highlight shows what I’ve selected. I then press Enter and it does unroll everything, but I get seams in places I don’t want them…

I hope I’m missing another crucial step.

Also, I’m fairly certain I need to squish it to get everything out, but I see no corresponding “Explode=Yes” in that command.

These are marklines of objects “welded” to your plate you want to unroll

Hello - if you have no curves that you know you want to unroll with the surfaces, skip (Enter) that step. Note you can use UnjoinEdge to open up locations where you know you want the seam to go on the result.


I’m afraid I did not understand what you said. This is my first time using Rhino, could you please elaborate?

Thank you for the tip!

As I suspected, though I think I need to squish it, because even though I reduced the size of my part to not make it curve as much, the flattened surfaces still did not stick together:


Could anyone explain how to squish a joined object without exploding it?

If you have objects attached to this curved object, their connection curves might get changed during bending. In order to get the locations of the “trace lines”, “connection curves” you select them so they are drawn on tha flattened plate.

In this way when the plate is cut from sheet metal (or plywood) and bent the traces will be exactly where they should be in order to weld (glue) the objects

Maybe not so clear, but I do not know how to explain, perhaps you don’t have objects attached to the curved plate so just ignore it :wink:

Hello - the surfaces cannot, judging from the images, be developed without opening a seam - if Squish does manage this, it will be a distorted approximation since there is no, if I am reading the image correctly, a ‘true’ developed answer that does not open up someplace. Imagine the 3d shape made from flat paper - can’t be done without seams or stretch/compress.


I am fine with some stretch and I even tried to enable the “compressionmostly” option, since this will be a canvas stretched over a steel support structure. Rhino apparently also provides tools to diagnose and measure the stretch, if I understand the documentation correctly, so I can give the manufacturer deviation figures.

However, I still don’t understand how to squish a joined object.

This is very interesting, but it seems to be mostly in Chinese. Can you tell me what I am looking at?

I think he uses a script that first unrolls in one direction then unrolls on the other direction a double curved plate.