Using match-up marks for fabric design projects (boats) and flattening

When I pattern my marine fabric projects, I tend to use “Squish” with mostly defaults. I believe my marks (example: Points) should match when I sew my components together. I would suspect they should be closer? UnrollUV doesn’t really work well with boat projects.

I guess I’m looking for tips or confirmation that the tolerance variation is normal? This is just a quick example… I’ve seen upwards of .5 and higher differences.



Hi Eric - I’d say that if the surfaces are developable, things ought to be closer than that - can you post the surfaces or sent to with a link back here in your comments?


Here’s the full project.

CockpitCover.3dm (1.4 MB)

This project isn’t “bad” per say. I’m just looking to make my projects better. When I put stuff together, my cutouts for poles and such are off by an inch sometimes. Partly sewing perhaps… but partly tolerances due to my match up marks being off.

Hi Eric - thanks, I’ll have a look - just fyi, remember this is a public forum when you post files - just in case it matters.
@pburgh.mcs - sorry, I had UnrollSrf in my mind, not Squish. Squish is going to be less precise - it probably pays to mess with the settings like PreserveBoundary.


It’s all good. Nothing really sensitive in the design.

Actually, the split on one of them wasn’t exact. Again, this was just an example so I’m basically looking for thing the may be wrong or better done?

I know… open question.


Hi Eric - I just tested the top and one side surface and one pair of points, with PreserveBoundary=Yes - the distance along the edges is not too bad - 8.97 and 8.98 on the squish, 8.98 on the input.


I have a custom button for Squish and I do use PreserveBoundary.

So just for confirmation, using Squish and having marks or points on the edges, the marks should be really really accurate, right?

Does different Surfaces matter? Say I have a more dense surface right next to a simple trimmed “Patch” panel.

Are there any courses that concentrate on fabric CAD? I did the normal Rhino course a few years back, but that was mostly ducks and cups… solid surfaces. (=

Hm - they were reasonably accurate in my test, but your original post shows something different, which is why I tested PreserveBoundary… since you are already using that, I do not know how to explain the difference… Can you post your macro that runs Squish so I get the exact same settings?


! _Squish

Not sure if you saw my other comment, but one of my splits was off. So my main question for this post was about how accurate match marks are using Squish. Are they safe and accurate for my workflow. This project wasn’t really an issue… I just wanted to capture my thoughts in pictures.


Hi Eric - ah, OK, sorry, I did not get what you meant earlier about the split being off. So, yes, it looks to me like the markers are pretty accurate in this example. My guess is you’ll want to keep an eye on things and verify, because different inputs might be more or less accurate depending on just how curved the surfaces are, but I’d be encouraged by the results of my test at least…


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Thanks, Pascal… you rock as always!