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The Center Seam Leg Block

This page assumes you've already completed the first six steps of the leg block. If you haven't finished yet click here to go back. We'll continue building the center seam block as step 7.

Step Seven

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21	Mark point 21 halfway between 19 and 20. This represents the height of the seam as it passes under the crotch. If you place it higher it'll cut your client in half, if you place it lower it'll restrict movement. It is an arbitrary position however. Square across the entire sheet.
22-23	Measure this line. It is waist to crotch plus half gusset. This is the length of the center front seam in the next step.

Step Eight

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22-23

Draft in a curve the exact length of the center front seam as determined in the previous step. If you're drafting on paper this is easier to do with a flexicurve ruler. Mark the distance on your ruler and then bend it to a nice smooth curve which ends on the halfway line. If you're using a CAD program there are a number of bezier features in most programs that'll help you maintain the line length while you curve.

23-24

Draw down a straight line from point 23 to point 24 about halfway between the thigh and knee. If you've drafted an even curve for the center front seam, point 23 should be a right angle.

Step Nine

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Mirror the curve from the center front to the center back and mark in points 25 and 26. Now look at the illustration below. The left image shows a lengthwise cross section through the the body. The dotted line represents the height of the thigh at its widest point. The new dotted line on the center image represents the line between the cheeks. The right image shows how the garment should sit on the body. Note it pulls between the cheeks and then sits down below the crotch. What you should also note is that the center back seam is slightly longer than the center front seam. It's not much, about half of the measurement 20-21 in step seven, but it's significant if you want the inseam to sit in the right place.

Step Ten

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Pivot the line 25-26 by rotating it around point 26 in order to lengthen the center back seam the amount determined in the last step. This is only necessary if you're making full length leggings. Recurve the center back seam as shown. I would leave the original line 25-26 on the block for when making shorts. Lastly, curve off the ankle cuffs so that they make right angles with the seams.

Step Eleven

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Remove unnecessary guidelines, points and numbers. Cut out or retrace the front and back blocks and true up all curves. Make sure you clearly label your block with a title, panel name, size, date, author�s name and version number. Do not add seam allowance to the block!