Sloper Magic Torf the Kiltmaker

A Sloper is a basic pattern with no seam allowance. You want a sloper that fits you. It can have no ease – a moulage. It can have fitting ease. It can have wearing wearing ease. It seldom has Design ease. Make one from a basic pattern. Make one from a well fitting garment, Draft one from body measurements.

Sources for Sloper design 1College textbooks 2Dress Kit (Sure-Fit Designs) 3Bodice Patterner (Bonfit America) 4The web ( 5The web ( 6The web ( 7The web ( 8Web tutorials (

Development A development is a three dimensional surface made from flat material such as paper, cardboard or sheet metal. Not all surfaces are developable. Singly curved surfaces may be developable. Cylinders are formed with straight line generators which remain parallel. They are developable. Cones are formed with straight line generators that intersect at a point – the apex of the cone. They are developable. Doubly curved surfaces such as sphere, torus, paraboloid, hyperboloid and the human figure can only be approximated.

A plane is defined by 2 lines, many lines, or 3 points. A plane can be folded on a line in the plane to make 2 planes with a line of intersection. A plane can be rolled so it’s generators remain parallel to form a cylindrical surface. The plane can be rolled so it’s generators intersect at a point to form a cone.

A sphere can be approximated by a series of cones or cylinders, A torus by a series of cylinders, A paraboloid by cones, A hyperboloid by cones or straight folds, But the human figure is more complex. A cone by a series of planes

Fit of a Garment For a garment to fit a person three measurements must match: 1Length, 2Width or circumference, 3Depth. Garments are basically cylinders and cones, both developable surfaces. People, however, are not cylinders and cones. They have lumps and curves That the designer has to march. This is done by creating cones with darts in the fabric. A front bodice sloper has one or more darts to accommodate each breast while the shoulders, neck, waist and arms are formed with seams. The shape of the back is created with one or more darts define the shoulder blades with seams to adjacent pieces.

Developing a pattern of the human body The body is not a developable surface but it can be approximated closely enough to be clothed by an easily machined material such as fabric. Steel body armor was made in a similar way. The body is marked at the extreme points and the seam lines. A triangle or plane can be drawn from The nape of the neck to the apex of the two breasts.

A second triangle intersects the first on the breast line to the center of the waist. Two more triangles attach the upper Triangle to the shoulders Two cones connect the lower triangle and apex to the waistline.

The apex I joined to the side seam by A cone. The side of the pattern is completed with A cone from the apex to the armscye. Finally the neck seam Is connected to the rest of the pattern by a cone with apex at the point of the shoulder.

The pattern of the sloper is made up of shoulder-to-neck cone attached to an upper front plane, a lower front plane and three bust cones to the waist, side and armscye seams. These surfaces are plotted to form the sloper (moulage). The final plot will have an opening at the apex. This is closed in a dart forming a cone producing the three dimensional shape (depth) for the breast. I suggest making a moulage with no ease. Make a muslin and adjust it to fit like skin. Correct the plot and add ease to make your sloper. The sloper is cut from tag or poster board. Typical ease for a sloper is 2 ½ to 3 ½ inch at the bust, 1 to 1 ½ inch at the waist, 1 /2 at armscke and shoulder. This ease is distributed through all seams.

Dart Manipulation A dart in a development changes the plane into a cone. The position of the dart has no affect on the shape of the cone. The sloper as plotted has one bust dart, a waist dart. This results in a bodice with darts as shown here. Waste darts are sometimes a problem as they should be aliened with darts in the skirt. We may, therefore, want to move the Dart somewhere else on the top. We can position it anywhere As long as the apex is in the same place and the angle of the dart is unchanged.

Moving a dart can be done in several ways. The easiest to follow is the cut and rotate method. To produce a French dart we trace the sloper onto pattern paper, cut it out, draw a line from the side seam where we want the dart to be, and cut along the line to the apex of the Dart. If you leave the last 1/8 inch uncut it will act as a hinge. The part below the cit is then rotated about the hinge at the apex to close the waist dart. The resulting dart has the same angle and apex as the original dart.

Horizontal under arm bust dart A horizontal under arm dart is created in the same way as the French dart. A horizontal cut from the side seam to apex and the part rotated to close the waist dart.

Cut and rotate to make an armscye dart. Cut and rotate to make a dart from the shoulder point.

Multiple Darts You may want to have more than one bust dart. To do this the waist dart is manipulated into several darts such that the sum of the dart angles is the same as the original. The two bust dart top is started as the side dart was with a horizontal cut to the dart apex. The segment is then rotated as before but only part way leaving some of the waste dart. The sum of the two darts is unchanged. The darts cannot be sewn to the same point so one or both are made to end at a bust circle drawn at the apex. The circle radius is 1 to 4 inches depending on cup size.

Multiple Darts More darts can be added with successive cut and rotate actions. 1 dart 2 dart 3 dart 4 dart

Princess Seams Darts can be combined into a seam called a princess seam. We start as we did for a 2 dart top. Cut where we want the seam and slide one section away to make 2 parts. Careful choice of grain lines Makes this different than a one dart top.

Princess Seams Princess seams are made by joining two darts and separating one pattern piece into two. Darts then become seams allowing curved as well as straight connections. Also color blocking is easy to do, almost inviting.

Dart Manipulation on Bodice Backs The back is not as dramatic as the front but is probably more important for comfort. The shoulder dart is easily moved to the arm with the cut and rotate technique. The top part can now be cut off and Slid up to form the yoke and back of the classic shirt. Slope back cut rotate cut Slide This is the back Of a classic shirt yoke back

The classic shirt can be cut from the top of the back dart to the top of the piece to give the pattern for a denim jacket. yoke Center Back panel Side Back panel

Cut to dart rotate & true top cut princess dart & slide. This is the princess back seam that’s been used in formal wear for 200 years.

Tools of the Pattern Maker