steps

The basic slack drape is the prototype for many styles of pants. It has one dart in the front and back, and cups slightly under the buttocks. It is slimmer than a trouser fit, but looser than a jeans fit. Unlike many other drapes, creating a pants drape requires a larger amount of drafting than actual draping steps on the dress form.

Take measurements

Take the crotch depth with a T-square. Measure from the center of waist tape to the top of the horizontal portion of the ruler. Record measurement.

Place a pin horizontally 8" below the waist at center front to mark the hip horizontal balance line (HBL).

Measure from the pin-mark at center front to floor. This measurement will be used to pin-mark the side and back hip HBL.

Using the measurement you just took, measure up from the floor and pin-mark the hip HBL at the side seam.

Measure from center front pin-mark to side pin-mark along HBL. Record measurement as front hip arc.

Measure from center back pin-mark to side pin-mark along HBL. Record measurement at back hip arc.

Back muslin preparation: Hip and crotch depth

Cut muslin to desired pants length plus 5" (You can make this anywhere above 3" depending on how much extra you would like at the hem). The width for the back and front muslin pieces must be a minimum of the back or front hip arc measurement (respectively) plus 10". You will need a large table and T-square or angled ruler to draft the basic slack.

Mark 7" out from top left corner of muslin.

Align the T-square with 7" mark. Measure down from top of muslin your crotch depth measurement plus 3" and mark.

With ruler in same position, measure down 10 1/2" for hip depth and mark. (8" plus 2 1/2" for extra along waist)

Make a third mark 2" above the hip depth mark. This will become the top of the crotch curve.

Draw a vertical line connecting bottom most mark to top of muslin.

Back muslin preparation so far.

Back muslin preparation: Hip arc

Align the corner of the T square with the crotch depth mark, and draw a line out horizontally to the right the amount of your back hip arc measurement. We will refer to this horizontal line as the hip arc line.

Align the T-square with the crotch depth mark again, this time facing out to the left. Draw a line horizontally to the left equal to 1/3 of your back hip arc measurement.

Back muslin preparation so far.

Back muslin preparation: Creaseline

Measure the distance of the hip arc line. It should equal 1 and 1/3 of your back hip arc measurement. Divide this measurement in half, and mark the centerpoint of the horizontal line on your muslin.

Using a long straight edge, draw a vertical line at this center mark spanning the entire length of your muslin. This will be the centerline crease of the back pant leg.

Back muslin preparation so far.

Back muslin preparation: Crotch curve

Using a french curve, draw the crotch curve from the mark 2" above the hip depth to left most end of your horizontal hip arc line.

Back muslin preparation so far.

Back muslin preparation: Leg opening and inseam

Take your desired pant length measurement and add 2 1/2". Measure this amount down from the top of muslin along the center creaseline and mark.

Align T-square at mark along center creaseline and draw out 4" to the left.

Repeat to the right.

Connect the leftmost end of hip arc line and leg opening line to form inseam.

Trim excess to 1" along inseam, and 1/2" along crotch seam.

Completed back muslin preparation.

Front muslin preparation

Follow the same steps for the front muslin, reversing the orientation. Use the front hip arc measurement, and instead of using 1/3 of it for the crotch curve, use 1/4 instead for a shallower front curve.

Pin prepared muslin to form

Pin inseams of front and back drafted muslins together. Pin to center front.

Pin to back, allowing the pant leg to hang down 1/2" from center crotch. As the muslin is trimmed to 1/2", the muslin should just touch the dress form. Adjust the height of front or back if necessary to ensure that the inseam is centered and balanced.

Smooth front portion to side seam, and remove excess muslin if necessary. Leave several inches beyond side seam.

Smooth back portion to side seam, and remove excess muslin if necessary. Leave several inches beyond side seam.

Fold and back muslin out of the way to allow for front drape.

Front drape

Move center front seam 1/2" to the right and pin.

Create a 1/2" wide, 3" long dart at the princess seam with excess folded towards the center front.

Add 1/4" tuck for ease.

Pencil rub side seam and mark at side waist.

Dot waistline.

Back drape

Begin the back drape from the princess line. The center creaseline should be slightly to the right of the princess line on the form. If this is not the case adjust the creaseline as necessary. Unpin the center back, align the muslin creaseline with the princess line, and pin.

Create a 1" wide, 3-4" long dart at princess line, with excess folded in towards center back.

Mark top and bottom of dart.

Smooth fabric back towards center back seam. It will fall offgrain past the center line. Pin and mark new centerline, tapering to meet old centerline at top of crotch curve.

Add 1/4" tuck for ease.

Pencil rub sideseam and mark at side waist.

Dot waistline.

Pin side seams

Trim front and back along side seam 1" from pencil rub line.

Pin side seams together, allowing 1/4" ease on both front and back the entire length of pant leg. Make sure the seam runs straight down. Adjust if unbalanced.

Mark front knee.

Completed drape

Front view of completed drape.

Side view of completed drape.