Let’s draft together the pattern of this dress.
Start from a basic block with darts.
On both front and back draw the halter neckline and the panels.
Divide each dart in two and discard the volume into the panel cut. flare at the hem 8-12cm on both sides of each panel.
Onto the front, draw two slash lines from the bust height to the neckline.
Cut through those and through the bust line.
Close the shoulder darts opening its volume in the lines you just cut.
Then trace the panels I, II, III separately.
Trace the back panels separately the same way.
Draw the collar as a rectangular piece (twice your neck circumference + the amount you want for the bow) and your pattern is ready!