I found a mistake in the way the pattern was drafted. it was a small mistake, but correcting it allowed the pattern to work with my measurements. I am uploading the corrected dress pattern. I will also post a few screenshots of my process in finding the error.
THERE IS ACTUALLY A BUG in the way the tool works. If the radius line from the center of the arc would not reach the line you are attempting to intersect, it will produce the wrong point. I will create an issue for that bug, but meanwhile it may be reasonable to add a tiny bit to that radius to make it work.
In the case of this particular pattern, the mistake was that the formula to place point BH on the back draft was
Line_A_H + (shoulder_tip_to_shoulder_tip_b - shoulder_tip_to_shoulder_tip_f)/4.
The correct formula was
(0.22 neck_circ) + (shoulder_tip_to_shoulder_tip_b - shoulder_tip_to_shoulder_tip_f)/2*.
I replaced Line_A_H with its formula as used in the front draft which was (0.22* neck_circ) I read this as one quarter of the neck circumference plus a factor to allow for the patternmaking method. To be precise it probably should not be exactly the same for the back of the neck in some people. This change did not affect the drawing of the pattern.
I replaced the “/4” with “/2” in the second part of the formula: giving the corrected formula that I used. I read this to be one (imprecise) fourth of the neck circumference PLUS the difference between the back and the front measurements of shoulder_tip_to_shoulder_tip. I believe it is incorrect to divide by 4 since the measurements being subtracted are both half body measurements. Therefore dividing by 2 will give the quarter body measurement which I think is correct. It is an almost imperceptable difference in the appearance of the pattern with the “manequin” measurements and it made a difference with my own measurements of letting the pattern draw correctly.Leilani_Dress_Kim.val (44.9 KB)