Grading up sizes with inaccurate results

increments
measurements
standardmeasurements
grading
curves

#1

Hello, newbie here again! I hope you’re all well. Now I’ve drafted my bodice and sleeve from Aldrich, I wanted to see how well my pattern would work as I stepped up the measurement chart. Unfortunately it ends up pretty bad! Some of my formulas and curves using the Aldrich book mustn’t be able to be scaled up correctly, and I was wondering if this is something I should be using the Increments feature for.

I don’t really understand how Increments work (but I am getting through watching stinde’s great video which demonstrates what they can do a bit). Are there any other resources to explain Increments?

Here’s an animation of the chaos just for fun!


#2

I just figured out my armscye increment up the sizes was incorrect, so that solves one problem at least!

Now that I’ve solved that significant issue, my next issue is regarding the armscye curve. As I scale up the sizes, the curve does not maintain integrity.

Size 22, base size:

Size 30 I would like the right side of the curve to stay as close as possible to A22-A38.


#3

I’d draw a curve from A11 to A16, then from A16 to A32, then from A32 to A40 and the last one from A40 to A29. That way, when sizing up & down, the curve will remain connected to those points.

You could do the curves in smaller sections if you wish to keep them connected to the inbetween points, as well.


#4

To have re-sizable curves, you need to use the ‘Curve with Points as Control Handle’, and use measurements and percentages in your formulas (no number values). This tool is only in v0.5.0.0.a, the test build.

Here is how my tshirt looks using points as control handles:


#5

You appear to have only 2 curves, A11-A32,A32-A29, which are shown on the Aldrich text to be 4 curves A11-A16, A16-A32, A32-A40, A40-A29.

A16-A32 is supposed to pass through A35, A32-A40 is supposed to pass through A36,

the lengths of A14-A35 and A22-A36 are variant depending on pattern size.

@slpencer does this new feature allow specifing pasing though a point ? @dismine is there a logic function iif/ if/then/else or a case/switch statement available ?


#6

Yes. Use ternary operator a ? b : c.


#7

The Curves with Points as Control Handles tool requires that all points are defined before using the tool.

In my pattern, the neck points P14, c1, c3, P7 were defined. Then I selected Curves with Points as Control Handles. I selected P14, c1, c3, P7 in that order. The curve is drawn, and will always be sized correctly.

None of the points in my pattern use absolute values (like 2cm).

c1 is based on (x of p7) and (y of p14) using the Point from x & y of two other points tool. c2 is midpoint b/w p14 & c1 using the Midpoint between two points tool c3 is perpendicular to line p7 to p11, and 1/2 the length of line p7 to c1, using the Point along Perpendicular tool

It’s actually more like the historical way of calculating patterns, based on ratios. Harkens back to when they didn’t have tape measures, only a set of cloth strips per client. So we use actual body measurements (or standard averages) to make the pattern points, then use relationships between those pattern points to create curves, facings, etc.


#8

Hi @slpencer, thank you for this :slight_smile:

Would it be an awful cheek to ask you to describe the way you do the calculations for the armhole and sleeve, please? I have the armhole working nicely but now the sleeve doesn’t :frowning:

I could send my file, but it’s a Christmas tree with little dots all over it.


#9

Is this listing of steps accurate?

Your pattern contains the bodice front & back, and the sleeve. The armscye curves were initially made using Curved Path (tooltip: Simple Curve). The armscye curves were replaced with curves made with Tool Cubic Bezier (tooltip: Curve which uses point as control handle). Result: the Sleeve cap no longer fits the armscye.

I need to look at your pattern (*.val & *.vit) to help you fix the sleevecap to match the new armscye curves. Pattern complexity is fine, it won’t be a problem.


#10

Is this listing of steps accurate? Yes, they work beautifully for the neck.

I’m just having difficulty in applying them to the sleeve & armscye :frowning:

My pattern resizes ok for size 30 and sews out very nicely for size 34.

What I have been doing since I found Valentina in February is… The local people have a ‘traditional’ dress that they call a Voorskoot. Directly translated, Apron. It is a straight forward bodice with a cross-over back, which has ties that one ties in a bow or something in front. It has short sleeves and a full circle skirt. Therefore, nothing really complicated.

My elderly friend bought a Singer hand sewing machine in December (since she doesn’t have electricity) with a view to make these aprons for extra income. She would like patterns that fit from 2 years old right up to over size 50. And I have offered to make these patterns for her. She has already made one in size 34 and says that it worked beautifully. She will bring it to me to see tomorrow.

But now I can’t make her a pattern in any other size as the armskye and sleeve pull skew and out of shape with the resizing. So I’ve changed the neck lines according to your method above but am totally stumped at the armskye and sleeve. Where do you get the points from that will be used with the Curves with Points as Control Handles tool?

While I am busy with this project, I am learning to use Valentina and also learning to make patterns in general, and I feel that it’s really a brilliant thing that you have contributed so much by providing the program that I hesitate to ask for lessons on pattern making. So thank you very, very much for all your help.

Voorskoot pattern.val (21.7 KB) measurements Voorskoot.vst (3.3 KB)


#11

Hey guys, apologies in advance for what is probably a trivial question. I’m also having issues with grading. Nailed the tee-shirt pattern but encountering issues with the sleeve. Namely the diagonal line between shoulder point and underarm. Is there a way I can anchor B3 to B5? Thanks :pray: :blush:


#12

Just by image i can’t say how did you create point B5. But even so. You did something wrong if you have two points in the same position.


#13

Good to know, thanks @dismine. If i’m not mistaken I think it’s a trigonometry problem, the lengths of B_B2 and B_B3 are known. So in theory I should be able to determine angle B? And then draw B2_B…??

I’m pretty stumped on how to ensure that the right angle is maintained whilst successfully scaling the other points. It’s Aldrich’s instructions so no doubt i’m missing a trick.


#14

I am curious, can you post here part that describe these points?


#15

@dismine here’s the excerpt:

Basic easy fitting tee shirt sleeve - Square down from B Line_B_B1 Jersey sleeve length plus 2cm, square across Line_B_B2 Half the measurement Line_A13_A5 plus 1cm. Line_B_B5 The measurement of the diagonal Line_A17_A18 on the body section plus 1.5cm, square down


#16

That’s not all. Where is B3?


#17

A little late night pythag but I got there… kind of… @dismine are you able to tell me why an error occurs when I try adding 1.5 to Line_A17_A15 please? I ended up excluding that detail :dromedary_camel:


#18

Point a mouse cursor above label Error (cm) and you will see tooltip with error message.

Probably it is your decimal separator settings. Try to change 1.5 by 1,5.


#19

No luck. Changed to 1,5 and it says “Parsor Error: Unexpected token…” when I change to 1.5 “Invalid Vvalue”


#20

Invalid value? Wow. Your calculation is wrong in some place. It return infinite or NaN.

Looks like sqrt returns this value. Remove it and see which value you pass to sqrt().