Squish surface, using slits to allow it to open up thus distorting less

I’m trying to flatten an upper from a shoe last to design a shoe. Squish seems to be the best command for this, am I right? The surface has a lot of curvature in both directions, and so there is a lot of stretch and compression. I would like to alleviate some of this by cutting some slits in the upper and allowing these to open up when it flattens. How can I go about doing this? I’m not even sure how to cut slits in a surface…


Hi sam,

You can’t directly add a slit to a surface that Squish will recognize. Lamina can do this www.laminadesign.com

In Rhino you can cheat by trimming a very skinny dart wedge where you want the seaming to appear. Or alternatively add detail seams (depends how many separate pieces you want coming off the cutting table of course).

Hope that helps, Steve

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What are detail seams?

I’ve tried adding a dart wedge kinda slit, but squish doesn’t seem to recognize it even though I have “SplitSeams” turned on. What kind of seam is “SplitSeam” supposed to recognize?

File is attached with original surface and surface with wedge seam.


Not sure if the file attached last time, so here it is again

Squishing.3dm(297.8 KB)

Turn SplitSeam off. It uses the seam in shapes such as cylinders and spheres.

I squished you shape with SplitSeam off and the result showed the small dart spread open. You may need several larger darts depending on how much deformation can be tolerated.

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Hi Sam,

Detail seams. I’m referring to manufacturing here rather than CAD modelling ie. seams between different panels of leather (or whatever your upper material is).

If you are trying to last that shape as a single piece, it’s going to stretch a fair bit. That may be OK, but I’d have a chat to the team on the factory floor before inflicting that on them. Oh, I forgot, designers and manufacturers are on opposite sides of the world to each other these days ;-.

“SplitSeams”? What David said.


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Hah :smile:

Looking at it again, it splits even with the “SplitSeams” on, it’s just that it seems to flip it for some reason so the seam is on the other side. Things seem to get rotate 180 I think. Any idea why that is?

But does work, thanks guys!

I’ve converted the shape to a single surface, kind of cylindrical like, with Pascal’s help. I would like to squish this, but it keeps overlapping. Any thoughts? File is attached.


I don’t see an attachment.

Whoops… file is attached. More a problem than the rotating is that it seems to kink, any tips on preventing that?


Squishing.3dm(236.1 KB)

Is this what you are looking for?

or am I totally wrong?

Close, but it shouldn’t be splitting on the back/bottom, that’s why I stuck the seam at the front… I could always attach it afterwards, but I’m going to be grading it and that would be a lot of extra work.
When I try to squish it with the seam just in in the front/top, I get all kinds of unpredictable results depending on control point counts and squish parameters, like the pic attached…