Patternmaking Bust Cup Amounts (Part 3: Bodice Block Essentials)See my YouTube Channel for all my videos: https://www.youtube.com/channel/UCiWmFg4YtA0t30V5da3YUeA Subscribe to be notified of when I upload new content.
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Hi, this is Maria from dresspatternmaking.com. In this video, I will show you how I arrived at the Bust Cup amounts that I use to draft the Bust Cups within my system and show you it’s the same thing as doing a Large Bust Adjustment, except that it’s done as part of the block making process.
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This is Part 3 of a 6 part series. I’ll be putting up one per week on a Sunday night. After these 6 videos, I will be remaking the Bodice Block videos. That’s the 2 videos that are already on YouTube. I’m going to be re-doing them. I’ve made some improvements to the system that I use. I have refined it.
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So the bodice Block Front and Bodice Block Back will be reissued as a new version and there will be an EPUB booklet that people can buy if they prefer to have a written copy to use. So they don’t have to keep pausing or fast forward or rewind the video. It will be in the same step-by-step format so you can do one step, swipe, one step, swipe..
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If you have watched the previous videos in this series, you’ll understand how the Bust Cup works, that the fabric at the side seam needs to go out on an angle because the Bust is bigger than the Upper Bust. The bigger the Bust Cup, the bigger that angle. So those wedges of color shown on the side of the block, in the left hand side image is the amount of fabric needed for four different bust cups.
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As I said, the bigger the bust up, the bigger that wedge is. Now this was covered in Part 1. So if this doesn’t make sense to you and you have watched that video, I suggest you go back and watch it. Now, that first video just explained the general concept, how the bust works, how the patternmaking bust cup is different to the bra bust cup.
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So in the image on the left, the red wedge, the smallest is the amount needed for a B cup. The green shading is for a C cup, the blue is for a D cup and the yellow is the double D cup. Of course, each subsequent cup includes the previous cup. The right hand side image shows how this is done when drafting the Bodice
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Block. The starting width of the block is the width of the upper bust, plus ease. Then a line is drawn to the left of the upper bust rectangle and the bigger the bust cup, the further out that side seam line goes. Now on the left of the measurements, the specific amount I use in my instructions to draft the bust cups within the block making process.
00:02:29:22 – 00:02:48:14
So for an A-cup the line to draft that angle is only 5/8 of an inch to the left of the Upper Bust Rectangle. The B cup is 1 and 1/4 quarter inches, etc. So I’ve had quite a few people ask: Where do these measurements come from? They don’t appear in other making instructions or books and they don’t understand them and they want details of how I came up with them.
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So this video is for those people specifically and for anybody who wants to know this. What I’ll be covering is (1) showing you how I accidentally stumbled upon it, (2) showing you that doing it this way achieves the same result as a Large Bust Adjustment and (3) covering the actual logic of it briefly. So although I initially stumbled upon this ability to draft the bust cups more simply within the block-making process, I’ve since worked out exactly how those figures are calculated.
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I will give you an overview how you could do the math yourself and with a bit of extra work come up with those exact numbers. I want to point out that when the bust gets larger, the center front seam gets longer, there’s more territory to cover, and the bust line and the bust point drops lower. So the bust line for the Double D Cup, the orange line is longer than the bust line for the B Cup, which is the pink line – partly because it is lower down.
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So as you can see, as the bus drops lower, the more width there is and the longer the measurement. So to move on, how did I come up with these amounts? How do they work? Well, first I’ll actually answer the question, how did I come up with these amounts, which is a different issue, to how they actually work.
00:04:00:04 – 00:04:18:18
So a long time ago I was testing some large bust adjustments because I wanted to see how they worked and I was using a 1-Dart Block. So one of the cut and spread methods to increase the bust cup is to cut from one of the dart legs up to the dart point, then up to the armhole to about where the front armhole notch is.
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So then there’s a hinge at the armhole and you spread to the desired amount and the textbook gives you the amounts to spread for an C cup, D cup and a DD cup. The instructions said to spread at the bust point for 3/8 of an inch. So the bust point is where you’re separating it and measuring it. Now, when I do cut and spread, I always compare the end result to the starting point so that I can see how the overall shape changes.
00:04:47:00 – 00:05:02:10
I always do it and I’ve learned such a lot from it. I was even tempted to go off on a tangent to do a little explanation of that, but I managed to restrain myself as that would have delayed this video. But I will eventually make a short video on that because it is a really good habit to get into.
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You can learn such a lot that will save you work down the track. So when I put one on top of the other, I saw that the main difference was that the side seam went out a bit more on an angle. The waist dart also increased a little. The armhole went out and up a little, so it went on to try the D Cup.
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The adjustment for the D Cup was to spread 3/4 of an inch at the bust point. I compared it to the block. Then I did the adjustment for the double D cup – that was spread 1 inch at the bust point. Then I looked at them all together. The original B Cup, the C Cup, the D Cup, and the double D cup.
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Then I had a light bulb moment. I thought if the B cup is drafted in the instructions by moving out one and a quarter inches from the width of the block, surely all of the other bust cups should be able to be drafted in the likewise manner but simply moved out further to match the angles I could see in front of me.
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Wouldn’t it then make sense to measure how far the C cup went out from the armhole? I measured it and it was 1 and 7/8 of an inch. Well, in actual fact, it was in centimeters. But I’ve already once had my whinge about the imperial system, so we won’t go there. So I measured the day cut and came up with 2 and 1/2 inches.
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So when I measured the Double D cup, I came up with 3 and 1/8 of an inch. Now, still keeping in mind that the armhole went up and out a little as well as it going out at the side seam – I will address that later. So then of course, it was time for testing. So how did I test it?
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So the first test may seem silly, but I thought I really needed to do it in reverse. I drew the lines at the measurements that I had come up with and brought my block in. And then I redid the large bust adjustments, opening up the amounts, the textbook gave again to see when I opened them up, whether they would hit those lines that I had drawn.
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So I spread the C Cup block 3/8 of an inch, and sure enough, it touched the line I had designated as the C Cup line. I spread the block for the D Cup insertion of 3/4 of an inch and it touched the D line. Then I spread it for 1 inch and sure enough, it touched the DD line. I bought a number of fitting shells and commercial patterns that came with a B cup, C cup, and D Cup. The fitting shells were a 2-Dart Block
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So I closed the side seam dart, so then I had only one dart. I checked the amounts to see if they matched up to what I had come up with and they were sure enough, the same. I also checked other textbooks for the LBA amounts and when I did the testing I kept on coming up with the same result.
00:07:38:24 – 00:07:54:18
Then after all that, I realized I didn’t even have to go to the trouble of converting a 2-Dart Block to a 1-Dart block. If you continue with the angle of the side seam of the 2-Dart block, making sure you are working with the correct side seam length (as in, you must take out the dart value and measure what’s above and below the dart)…
00:07:54:24 – 00:08:17:04
So using the correct side same length – still came up with the same result. Now this is off on a little tangent. When I was studying pattern making it taste. Back in 2006, I purchased the fourth edition of Joseph Armstrong’s book, which was published in 2005. Now, information about drafting bust cups within the block making process wasn’t mentioned in that version.
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In my last video, I told the story of how I was trying to work out ease in Joseph Armstrong’s bottom block. And I noticed that the Front Bust Arc and the Back Arc did not add up to the bust measurement in her measurement charts. This means that the starting width when drafting the block wasn’t actually the bust measurement.
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It was the bust measurement plus one inch. Then the two inches ease was added on top of that. Now, I wasn’t sure if this was a mistake in her textbook. So I decided to buy the new 5th edition of the textbook published in 2014 to see if that information was still the same. I was going to work under the assumption that if it had been a mistake, it would have been corrected in the later edition.
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So I purchased that textbook to check on the Bust Arcs. But then in the process found out that the recent edition did have some information about including a larger bust within the block making process. Now, when I first saw this, I have to be honest, I actually thought, “Oh, no, some people are going to doubt that I came to the same conclusion independently.
00:09:20:11 – 00:09:40:08
They’ll say I took it from Joseph Armstrong’s textbook”. But and a big but if you look at the amounts given in the textbook which are on the left hand side under the Bust Cup Formula, they are not the same as mine and they actually make no sense to me. In her instructions, the B Cup is measured from N to P, so that’s the equivalent of mine D to E.
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And apparently in her system for a C Cup from N to P is 7/8 of an inch, a D cup is 1 and 1/2 inches, and the DD cup, though in the textbook it does actually say D again, is 1 and 3/4 inches. So again, those amount to nothing like mine and they don’t make sense to me. The most obvious problem being that the C Cup is less than the B cup, but none of those amount anyway match up with mine, even if that was just a typo.
00:10:08:21 – 00:10:26:24
Anyway, this version of Joseph Armstrong’s textbook therefore does imply that you can get a larger Bust Cup by going out at a bigger angle at the side seam, as I came up with independently. But again, the amount she gives doesn’t make sense. And I will show you in the upcoming slides that the amount I use are mathematically sound.
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And just one thing further to that, even if Joseph Armstrong’s textbook did include the same amounts as I had, it still wouldn’t work out correctly because Joseph Armstrong’s instructions are based on the Bust measurement. So if you used her instructions to draft a block for a woman with a 38 inch bust but a double D cup, then that woman would end up with eight inches ease in the Upper Bust.
00:10:51:12 – 00:11:13:14
And I’ll cover that in detail in my next video: Why upper bust? And I finally realized that I didn’t even have to do all that work, checking other Blocks and Fitting Shells It’s actually pure math. When I apply the math, I consistently come up with the same amounts of 1 and 1/4 inches for the B Cup, 1 and 7/8 inch for a C Cup, etc..
00:11:13:21 – 00:11:47:07
So to break it down, the upper bust is a few inches smaller than the bust. It’s obvious we need an angle to go from the smaller measurement to the larger measurement. So that angle is the result of the difference two inches, three inches, four inches, etc. But the angle on the body is different to the final angle on the block, because that final angle on the block includes 1.25 inches ease at the upper bust, and that ease is tapered down to the waist because we don’t need all of that extra 1.25 inches at the waist.
00:11:47:18 – 00:12:05:13
We don’t need that the waist because that initial angle from the upper bust to the bust already gives us more than the amount of ease we need at the waist. So I’m going to take a C Cup as an example. Of course, the C Cup is defined as the upper bust being smaller than the bust by three inches.
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So the image shows the body measurements for the upper bust and the bust. So currently in this image there is no E’s at the upper bust or the bust. Now what you can see is the angle on the body from the upper bust to the bust, where there is three inches difference between those two measurements. Now, the length of the pink arrow, which is the measurement from the upper bust rectangle, is currently three and one eighth of an inch, which is more than the 1 and 7/8 of an inch for that cup size.
00:12:36:20 – 00:12:59:17
But it’s more because it’s currently on the angle needed for just the body measurements. When we add in the 1 and 1/4 inches ease, we will end up with the 1 and 7/8 inches out from the upper bust rectangle because that upper bust rectangle will include ease. When the ease is added in, it’s added like shown on this slide.
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The green shading is showing the ease that needs to be added. This means that the top point of the side seam at the upper bust will be moved over one and a quarter inches to add in the ease. I haven’t moved it over yet. I will shortly. But first I want to show you how it’s not going to be added.
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Now I’m showing you where or how the ease is not added. It is not added evenly down the side seam. Now, this may be a bit confusing for some because this is how ease is added when using your block to draft a pattern, you often add it, or at least some of it, depending on how much you want to add evenly down the side seam.
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However, this is the block and this is where we’re trying to get the initial necessary fit. After this, after we’ve got the necessary fit, we can add it evenly down the side seam when we want extra ease. So therefore, if we added it in as shown, we would have a further one and a quarter inches ease in the waist that we need to take in somehow.
00:13:57:07 – 00:14:21:06
We already have a lot of extra ease in the waist that we don’t need and we’re going to have to take in with darts. So we only need to add it in at the Upper Bust, not down at the waist. So we do need to maintain that current waist point that we have indicated by a star. So to add it correctly, we only need to move the top point of that side seam across to include the ease amount.
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When we do that, we have increased the width of the upper bust rectangle. When we now measure from the upper bust rectangle, the measurement is one and 7/8 of an inch. This works with all the bust cups, though of course there’s different amounts, different angles and different measurements. But the logic is the same. Remember that with different Bust Cups, the bust is lower.
00:14:41:23 – 00:15:02:03
So if you’re checking the bust measurement, if it does work, that bust measurement, if you’re getting enough ease, remember, the bigger the bust cup, the lower the bust level. Now, if it’s your own block, then it’s not a problem because you will have your measurement of your Bust Depth. But if you’re doing this as an exercise and increasing the bust cups yourself and trying to see if this works, you need to remember that.
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And also just another note, the center front length also increases. And I actually haven’t shown that on that image. So in summary, these amounts are nothing other than the result of a simple math calculation taking into account what needs to be taking into account, which is the ease. You need, the angle that’s required to draw a line from the upper bust to the bust.
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You then need to move the top point so that the ease is included in the upper bust. Now, I said I mentioned the fact that when you do a large bust adjustment, the armhole moves up and out and that’s not included when you’re drafting the block with my system. Now, the reason why I ignored that, as it were, is because when you draft your measurements, you draft to your armhole depth and you draft to your width.
00:15:45:12 – 00:16:04:14
So this doesn’t need to be done. This is necessary when you’re starting with a standard block and you’re making those adjustments to make it fit a nonstandard figure with a larger bust, which usually has a wider block with a higher armhole. So again, with my system, you’re starting with your own measurements. So that part of the large bust adjustment is already built into my system.
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Now, if somebody is thinking that I should have just explained the math of the bust cup, rather than make a short story long and tell my story of how I first saw it, there is a reason that I told you that story. And my point is that if you really want to learn patternmaking, it’s really valuable to compare the initial and final result
00:16:23:10 – 00:16:46:14
when you do cutting and spreading. When I first started telling that story in this video, I almost went off on a tangent to show you how important this is, how much you can learn. I restrained myself and didn’t go off on that tangent and it’s a good thing. Otherwise this would have taken me a lot longer. But I will in future do a short video giving various examples of how much you can learn by doing the comparison of the before and after of cutting and spreading.
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So next week I will cover Why Upper Bust. By this time, if you’ve watched the first 3 videos, it’s probably quite obvious why the Upper Bust is important. But I’ll just summarize it. Hopefully that will actually be a really short video 10 minutes or so. If you find my tutorials helpful, consider supporting me by buying me a cup of coffee on Ko-Fi.
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Click on the Ko-Fi link in my channel header.
This is Maria from dresspatternmaking.com
Beautiful dreamer, wake unto me
Starlight and dew drops are waiting for thee.
Sounds of the rude world heard in the day
Lulled by the moonlight, have all passed away.