Greetings, a question or 2

Greetings from the US middle of nowhere.

I found seamly2d a couple of days ago, and to my delight, it works on linux (with flatpack AND appimage, wooohoo, cause everyone wants to use appimage these days, and I really dislike that).

I’m somewhat ok with drafting blocks on paper (always have to refer back to instructions), and decently good with modifying those blocks for the stylelines I want, again on paper, and have been searching for a way to digitally draft to make better use of my new projector for sewing patterns so I’ve been exploring the software a bit. And now, I have a few questions.

I’ve been working on creating a moulage (following Suzy Furrer’s Craftsy Bodice Sloper class, which is - apparently - a slight modification of a couple of chapters of her book Building Patterns: The architecture of Women’s Clothing). I believe the draft instructions are compatible with seamly - not all that different really than Joesph-Armstrong - however, I have a bit of a problem. My figure is far from close to the standard figure, and trying to apply my measurements to any parametric draft becomes problematic (often times the drafts just don’t work with my measurements, but, I’m looking to try again in the chance that I was doing something wrong on paper).

If I can’t get a good/close enough draft from measurements alone, my fall back plan is to use standard measurements of a size that fits my shoulders, and then start making various adjustments (rounded upper back, square shoulders, full bust, full belly, maybe straight lower back, at a minimum, possibly others in addition to the fine tuning of darts and curves). Can Seamly handle these kinds of adjustments to the block? If so, are there any tutorials anywhere that show how to handle them (not the instruction on how to do each one, just how to do slash and spread in general)?

I’m also curious and the documentation has not been all that clear so far, when you take a block that was properly done with formulae, and then “cut” it up for your piece details, if you apply a new measurement file to to this “cut up” block, would the pieces adjust as well, or is it just the basic block that adjusts? As a for instance, say I have 2 family members that are close enough to standard figure that an unmodified torso block works for them with limited adjustments, person A and person B. I draft a torso block using person A’s measurement file, save it, then save as a duplicate, and create details to make a princess seamed dress. Could I open a duplicate of the dress pattern and apply person B’s measurement file to it and be good to go, or would I have to open a duplicate of the block, apply the new measurement file, and recreate the details of the dress all over again?

Final question, for now. Regardless of which of the three draft methods I’m looking at, the dart widths come from tables that can be formulaized. There are two options for getting those widths in, an unknown measurement on the measurement file (requires keeping the tables handy), but, I’d rather do variables with an if-then-elseif-then structure (usually a total of 4 options), can the variables handle that deep of an if-then-else?


Yes… since any pattern pieces are based on the geometry of the point and curves nodes that make up the main path (or internal paths) - they will automaticall adjust to any changes in the draft block due to a change in the measurements.

Oncce you have a pattern drafted and pieces created with what ever details you add, all you need to change the size is a different measurement file. You can load a new (individual) measurement file as shown below. It should be noted you want to avoid having any duplicate copies of a pattern file with the same name open at the same time. Tha app will warn you that the file is already open. You can make a copy with a different name, and that’s perfectly fine to have both open.


Disregard the Multisize for now… it’s a more advanced method of creating your patterns that you’re not ready for yet. Heck… I’ve been using & programming the app for at least 4+ years and I still don’t understand the Multisize. :slight_smile:

I believe you can nest ternary ops… check out this topic: Math Functions - Nested IF statement


Hello & welcome, @nightshiftKnitter (from South Africa middle of nowhere). :grin:

This topic can serve as a basic instruction on the slash & spread. The software has improved since it was written & I was just learning the software, myself (and patternmaking). Since that time, I can assure you that, if you can do it on paper, then you can do it in Seamly - slash & spread, move & rotate, mirror…

Ok, so I haven’t even heard of Suzie Furrer, so I don’t know anything about her methods, but if they’re similar to HJA, then I’d suggest that you create your basic drafts (moulage) using a multisize measurement chart, anyway. This way you can test that your curves, arcs and lines meet over a very wide range of sizes, even if those sizes don’t increment properly, but rather generally. Once your pattern is created, then you can load in your personal measurements (very carefully taken) and sew up a text moulage and check the fit before making any adjustments to the draft.

Gina Renee Designs has written an amazing book on fitting problems that one can buy and also has a few small (free) ebooks on the subject in her tutorials section. And yes, Seamly can handle these kinds of adjustments.

Yes, yes, yes!!! This is totally magic of using Seamly. You don’t even need to duplicate the file, just go Menu > Measurements > Load Individual > Select the measurement file and everything should just readjust/resize - like magic before your eyes - and you’re ready to start cutting with your new projector :star_struck:

Normally, I keep my basic pattern intact as a master pattern. This I duplicate by Saving As ??? and then start changing and adding to create the design required (this way, I don’t have to create the master pattern from scratch each time).

Yes, it can. You will just need to structure it very carefully… If A>B, then T, otherwise if A>C, then U (and you can carry on for quite a while like this), otherwise Z. However, you can’t use actual line lengths or curves in the Variables, so I’d suggest that you use the Measurement File codes to get the formulas to resize according to measurements.


Thank you! I actually learned after posting that her method is closer to Kenneth D King (and possibily GRD, I haven’t had the opportunity to take her course) which was based on Ecole Guerre-Lavigne - which may be more internationally known.

I think I’ve worked out how to handle most of the tables, the hardest one is the bust darts, which depend on cup size - which uses the bust - (underbust + 4 or 5) (depending on if odd or even) method. I THINK I’ve worked out the formula for assigning a cup value (would be numeric instead of alphabetic, just to make other formulas easier, since it’s only used for finding the dart size, I just need to figure out how to use modulo in formulas and structure the ternary correctly for that.

I’ve been working on building a measurement file using a set of standard measurements, and discovered I need a fair few custom measurements to cover a lot of the calculations - this is probably mentioned somewhere that I’ve missed, but is there a way to save those custom measurement names and formulae, or do most people just create an empty/no values measurement file and copy that for new individuals when this kind of thing comes up?


I should add a “Load Template” item that is more or less loading an existing pattern and saving as another name… difference being the order in which it’s saved. With a template you’re asked for a new name when you load it, instead of when you save it. It avoids the possibilty of accidently “Saving” over the file by forgetting to “Save As” and using “Save” instead - or if one is like me I hit Ctrl + S without thinking.


Sounds good, @Douglas. I’m so used to opening my master and immediately Save as before even touching it, that I forget that there’s a template option :grin:

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Yes, I think that depends on whether you’re making a bra or a dress. I normally use the half measurement across the bust front minus the half measurement across waist front to determine the size of the dart at the waist, since I’m reducing the fabric from covering the bust down to covering the waist.

Once you’ve set up your multisize measurement files, then you can go ahead with drafting. Once you’re finished with your basic pattern, you can create an individual measurement chart and Import the measurements used in the pattern directly from the pattern into the new measurement chart. Then you’ll only need to add the person’s measurements. This way, you won’t need to go hunting through all the codes again or remake all the customs.

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I think I may have accidentally confused things with my example of drafting for multiple family members as a way to make sure I was understanding how blocks and patterns get adjusted to new measurement files. I have no plans to draft for anyone but myself (and, possibly my husband, a completely different draft), would I still need a multi-size measurement file? I don’t know where to find such a file with all the correct measurements for this system. My previously mentioned standard measurement set is actually just for 1 size.

As for using, or not using cup size on a dress pattern, this system results in a bodice/torso (technically a moulage) front that looks like this Screenshot from 2023-06-30 03-20-20

without having to rotate some of the width from the waist dart, how wide the shoulder, armscye and side dart are is from a table based on cup size, the waist dart width comes from a table based on waist and hip difference. (by the way, rint and fmod do not seem to want to work with the ternary, that’s ok, though, I can work around it)


If the size chart isn’t going to change, then no, you can use your own personal measurements for drafting. I make patterns for people of various sizes, so I like to use a multisize to make sure it will work for almost any size. Sometimes, a system uses a distance from 2 nodes, so the intersection of the 2 arcs will determine where the node goes. If you resize the pattern, and the arcs don’t intersect, the node gets placed at the top of the pattern and anything else that is based on this node appear in very strange places or they’re of very odd lengths, etc.

Ah! ok. Yes, if the pattern system explains how to get the dart width, then most certainly go with it.

Yes, it’s either one or the other. You can do the conditional formula in one Variable and then the rounding in another just below it on the results of the conditional.


Not really. If you’re just making pattern for yourself or hubby, using individual measurements is sufficent. Actually even using “custom” individual measurements for more than 1 person is perfectly fine. The multisize measuements are for when you want to draft a base size pattern and then export it as a set of graded sizes. For example you draft a size 12 dress, and usimg a multisize table it also creates say a size 8, 10, 14, 16, an 18. And to @Grace point, when using multisize you can restrict the range of sizes so that you know the pattern works within that range… which when using individual measurements you can input meansurements that go beyond what the pattern can size to. For ex: You can’t just take a mens 38R jacket and expect to size it to a 65L. That requires a different draft for a Large and Tall which has different proportions.


Speaking of this, where might one find drafting systems for Big and Tall? If I do, eventually, draft for my husband, I will definitely need to know those proportions (Tall, but borderline on the Big, so it’s it’s one that can accommodate varying levels of Big without giving up Tall would be even better).

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Well, my experience in pattern making mostly revolved around mens period costumes… so some of the systems I used are probably not what you would need. I did use several books published by The Master Designer. I’m sure though that anything from M. Müller & Sohn would work.

That beign said… I probably should have been a bit more specific. Some of the men’s systems will accomodate someone who is bigger or taller. Where a draft needs to change is when the body shape changes. That generally means when instead of the waist being your standard 6-8 inch drop (from the chest) it nears the same or is bigger than the chest. If you just sized up a 38R to 48L for someone is corpulent… it just won’t fit the waist, nor will it hang correct.

Also, in reagards to sizing up or down with different measurements. Often in drafting patterns we rely on lines intersecting other lines, curves, or arcs… and sometimes if you go too big or too small an intersection may not happen, at which point the pattern can do strange things. That’s where @Grace’s point was that in using the multisize you can control what sizes a pattern draft produces so that you know it’s drawing all the sizes correctly.