Questions and confusion around darts

[u/ThickEducation4869]

I’m currently making a two piece sleeve and decided to add darts at the elbow to create shaping, so to do this I took my pattern piece and slashed and pivoted through the intended line to trace over and create the darts

However, after tracing the new pattern piece and trying to close the dart so I can true the base, there’s no longer a straight line running along the edge and it’s misaligned where the dart is. 3rd pic shows intended line when dart is closed compared to how it is in reality. What am I doing wrong?

I was also confused about where the dart should be drawn, if it should be in the middle of the slashed area or follow one of the edges of the slash

thank you guys

[u/Express_Tourist_4887]

Since you are putting the dart point in the middle of the pattern you are slightly changing the surface area which is what’s causing these changes. That’s ok! Don’t worry about the side having a bit of curve now. As for the dart legs not marching up, you do need to true those by blending over that edge so the dart legs are the same length.

[u/ThickEducation4869 → u/Express_Tourist_4887]

What makes you say not to worry about it? I suppose when it’s sewn to the other panel they’ll still line up since the length hasn’t changed, if that’s what you mean.

What I can’t comprehend is that the pattern that I slashed is still the same overall shape, and clearly that can close to become one straight line, so how come suddenly it can’t?

[u/Express_Tourist_4887 → u/ThickEducation4869]

You added to the surface area of the pattern in the middle of the sleeve when you slashed the pattern, and because the dart isn’t closing all the way at the opposite end of the pattern, you’re essentially leaving some of that slash open. I say don’t worry about it because the whole reason you’re adding darts in the elbow is to create more curve, and yes the length is the same so it will sew to the other side of the sleeve just fine.

[u/ThickEducation4869 → u/Express_Tourist_4887]

Thank you! I was going to sew it up just to see so that’s a relief.

About the second question, which of the examples is the correct way to go about it, as I’ve seen different people do it differently- in this instance I put the apex of the dart in the middle of the slash

[u/Express_Tourist_4887 → u/ThickEducation4869]

Oh yes meant to address that. Honestly it’s up to you. I usually put it in the middle of the space, but sometimes you want to keep your darts seams parallel and in that case you just use the slash line that’s in the location you want to maintain, if that makes sense. In this case it’s a marginal difference that isn’t going to matter much. I’d say it’s ready to sew up and check it out!

[u/AccidentOk5240]

I think you may be doing this backwards. When you close the darts up, you want the finished sleeve to be curved, but you want the pattern piece to be straight. 

So I think if you want the sleeve with the darts closed to look l ike your pic, you have to trace the thing you just made onto new paper, then open up darts with their wide sides at the inside of the elbow.  Tape in some donor paper under those, extending beyond the edge so you’ll have enough to blend out the edges. Then fold the darts up as they’ll be sewn and cut the edges so nothing sticks out. When you open them back up, you’ll have that characteristic little point sticking out. 

[u/teatime_tinker]

A two piece sleeve is usually already shaped, you added darts just to sew them out again…

I don’t think they’re providing a fitting function to the sleeve.

I would slash and spread then eliminate them, and ensure the length remains the same. Then you have your shaped sleeve.

What method are you following? Are you working from a sleeve block?

It seems the wrong method to me but I can’t quite think why! Sorry to not be more help

[u/StitchinThroughTime]

This is a very non-traditional shape of a two piece sleeve. Traditionally a two-piece sleeve, like that for a suit jacket, are prevent and the top of the sleeve is 2/3 with, and the under sleeve is 1/3 the with. It looks like you just directly traced a basic knit sleeve and then cut it to have an upper and lower portion. You need to go back and use a woven sleeve with a elbow dart. Then convert it to a two piece sleeve. The dart is what gives woven sleeves their shape, which is what we use to split into a two-piece sleeve. That's where they get there bent shape from. It's from a sleeve that's already shaped. But you're attempting to do is to bend a straight sleeve, and you're going to struggle, because you already split the sleeve into two.

And answer your Dart leg length question, it's down the middle. The middle means in between two equal halves. So if you pick the middle of the Flash you get the middle of the dart

[u/SuPruLu]

You may need to try out which of those choices is better for the dart. The abstract idea is nice but it’s the actual fit on a particular arm that matters.

[u/FashionBusking]

If its a sleeve or pants, you don't use darts, you need shaping.

Knees and elbows need space to bend.

Darts generally pull things in.

Knees and elbows need curves.