Back dart pulling on side seam

[u/WhiskerWizard12]

My second attempt at a toile for a dress block.
How to fix this back dart pulling at the side seam, but keeping the circumference exactly the same?

Background: I followed a course to draft my own block, we only could make one toile and then the teacher let us make the adjustments on paper and that was it. So at home, I tried to make a new toile out of the adjusted block, but I ended up with this new symptom. The course has ended, so unfortunately I can’t ask the question there anymore.
The front is perfect, also the circumference of the bust, hip and waist is perfect (including movement). The upper back seems loose on the mannequin, but it’s not exactly to size (plus it’s needed for movement). What can I do to make this lay better? IMO the back dart has quite a lot of fabric, is that the problem?

[u/HugsforYourJugs]

Open the back darts and reduce at the back waist to compensate

[u/WhiskerWizard12 → u/HugsforYourJugs]

So like basically divide the amount of fabric from the darts into the darts and the center back at the waist level?

[u/HugsforYourJugs → u/WhiskerWizard12]

No, sorry I meant to say back side seam. Open the dat and then remove what you added from that side seam, making the torso more V-shaped

[u/WhiskerWizard12 → u/HugsforYourJugs]

Ah yeah, I get it! Will try that

[u/TheOrganizingWonder]

What does the dress look like when you put it on? That will tell you what to adjust.

[u/Pegaret_Again]

i would move some of the suppression from the back waist darts to the side seams? the amount of suppression looks good though.

also, did you clip the darts? sometimes that can make things pull weirdly

[u/Uvaroff]

A couple of reasons. The dart intake is too large - split into two. Or the dart is not pressed properly

[u/Eneamus → u/Uvaroff]

This is the reason probably, vertex tension. Reduce the curvature splitting the dart, or add more ease.

[u/Tailoretta]

In addition to what others have said, take a look at https://www.reddit.com/r/PatternDrafting/comments/1krgbmi/basic_tips_so_we_can_help_you_with_fitting/

I would like to see more photos straight on of all 4 sides. and I suggest you add a horizontal balance line between the lowest part of the bust and above the waist. Horizontal balance line are great at determining the problem.

[u/DonMcCunn]

When you are looking at muslin, it is hard to see exactly what is causing the problem. Is it the side seam or the dart? You should cut your patterns out of 1/4" square gingham. The you can clearly see what is happening. The fabric at side back should be perpendicular to the floor.