Bug: Seam Allowance sometimes doesn't create "corners"

Anyone else notice this problem? The transition between seam allowance widths sometimes doesn’t create a “corner”.
Selecting different options in the Angle dropdown field didn’t change this result in any way. I’ll try to figure out when this problem was introduced, because I’ve created patterns before with a proper zipper extension.

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For what it’s worth, I was not able to easily replicate the problem in 20201005 nor 20201012 Linux AppImage on Ubuntu 20.04.1 LTS:

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Do you have a pattern this is not working with to test?

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I’ve been having problems with this for quite a while now. In some instances, the direction selection work and in others they don’t do anything and in others, I get some weird & wonderful seam allowances. :slight_smile: But it’s been for quite a long time now, it’s not recent. I’ve been adding bits to my patterns to get it as I want it.

Here’s a pretty simple bodice that you can test on @Douglas, I’ve already put in the extra seam allowance on the bodice front.

Aldrich - Bodice Chemise.val (24.2 KB)

Aldrich Measurements.vit (2.0 KB)

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So this would be before any changes I made to the handling of notches?

Thanks Grace… I’ll have a look later.

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I’ll have to check and see if there’s a difference between the right angle on the 1st vs second edge. You used the 1st, Susan used the 2nd.??

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I tried both, both worked.

I could be wrong, but I think I’m right - that it’s been from before your upgrades.

I tested them all. The seam remained the same.

On a different pattern that I tested on the sleeve cap curve, I got this with the 1st 4 options:

image

And on the last 2 options, I got this:

image

But I think this is only recent, but I can’t ever remember doing this, so I’m not sure.

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I was using a Windows build from Oct. 1. Here’s the pattern & measurements:
20201011_MyFrenchDressBlock.val (43.3 KB)
20200331-Susan.vit (7.3 KB)

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Wow… I don’t even know where to begin on this one. Oy vey.

One thing I can say is a problem is preexisting at least going back to the Aug 3rd build… and I would assume before that as no other changes have been made regarding the seam allowance. And the problem get’s even flakier than not creating a right angle transition.

First off one thing I noticed in the seam allowance dialog is that if you type in say 1. it gives an error. The dialog line edit SHOULD complete the entry to make it a real number 1.0. In fact if you even just type 1 and hit return in it should complete the entry and make it 1.0.

decierror

Now here’s a test I did with the Aug 3rd build - before I added any of the Notch updates…

Here you can see it’s doing the same thing exhibited by Susan’s example…

And here all I did was change 1 to 1.01 and Yikes! I have no clue what it’s doing??? satest2

Now here’s Susan’s pattern (in a Sept build) changing the seam values:

Changed 4 to 4.01 and found the lowest I could go before it flipped out again - 1.275. notice the transiton is right at the BustC3 node. Susan1

Now if I used 4.0 notice how the transition is past BustC3… probably 1.275cm. Susan2

And the I found the highest highest value I could go - 1.258 and leaving the 4.0 vlaue alone, the transitio is back to BustC3 ??? Susan3

In other words - at least in this instance - if the after value for BustC3 was between 1.258 and 1.275 the seam would do what Susan showed in her example.

OBVIOUSLY something is amiss. Since I always use inches with 1/2 or 1 inch I’ve never seen this issue before. As soon as I get a chance I will take a look at the code to try and determine what is going on.

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Here is the same problem that someone had a few months back: Issue: Curve's seam allowance doesn't work properly in latest version

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Here are the patterns again that I’ve tested on the January 2018 build:

image

Aldrich - Bodice Chemise.val (24.3 KB)

Aldrich Measurements.vit (2.0 KB)

You can see it’s doing the same all the way through the options:

image

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Thanks Grace… sort of confirms there has been an existing issue with the seam allowances and the corners / transitions. It’s very odd how changing one of the before or after’s by as little as .001 can cause the seam allowance to do strange things. It seems once it doesn’t like the values the angle choice has no effect.

At first I thought it might have to do with the cm conversion factor, but it started doing the same with inches once I used an allowance like 1.01.

I’ll figure it out.

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You’re very welcome :slight_smile: I had to wait to get to the PC where I had the 2018 Seamly to check my facts.

Thank you very much for all you guys are doing. :star_struck:

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I’ve also noticed this happening with seam allowances… it may or may not be related. If you notice the corner at A1 is cutoff even though all 3 points are set to the same corner angle This seems to happen once the angle goes below a certain number of degrees. Since I’ll have to dig into the seam allowance routine(s), I’ll try and fix this case too.

saerror3

Reducing the angle at A produces this…

saerror4

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Can you try Susan’s pattern on the Linux ver using her seam allowances in her example. I’m guessing its a code issue and not a Windows vs Linux issue, but would like to rule that out.

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Yes, I’ve seen that recently (in the last 3 months or so). It changes a bit with the different settings.

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True… but in my examples all 3 corners are by length and should come to a point. I don’t think it’s by design, even though I would probably never cut a pattern with that sharp a corner - I tend to knock the corners off - there’s something wrong. Something in the code is making it produce 2 seam allowance points at the node instead of 1… just the opposite of what is happening with Susan’s pattern.

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Isn’t it limiting the point to the width of the seam allowance and cutting it off? It looks like it’s making a decision that if the length of the point is over 150% of the seam width then…

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Confirmed. It does weird things here too. Check out a 5cm zipline!:

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