What is a Sloper?
Following is a letter I wrote to the chat list a few years ago:
One question often asked by "newbies" is "What is a sloper?"
This description is not intended to change everyone who has been using "sloper" to name what I would call a fitting shell, but is only mentioned to clarify and educate and explain why we have naming confusion among our PMB fans. I studied fashion design at a state university in the 70s, and have worked in the industry as a patternmaker and designer.
From the first chapter of Patternmaking by the Flat Pattern Method by Norma R. Hollen 3rd edition, 1972:
The BASIC PATTERN is the "starting point" for Flat-pattern designing. It is a simple pattern that fits the body with just enough ease for freedom of movement and comfort. The basic pattern has five pieces: bodice front, bodice back, skirt front, skirt back and sleeve. The basic pattern is sometimes called a master or foundation pattern. The drafted pattern is referred to as a block.
The SLOPER is a cardbaord copy of the basic pattern that has dart area and seam allowances cut away. It is used with the pivot method of Flat-pattern designing.
A MUSLIN SHELL is a bodice or skirt, made from the basic pattern, that can be tried on by the individual for fitting or designing purposes.
The sloper for the PERSONAL pattern is a cardboard copy of a commercial basic pattern that has been previously ALTERED TO FIT. All slopers are made without seam allowances and the dart allowances are cut away.
Does the basic pattern sound like the first garment we make in Boutique? It is! As people have said, this garment is not designed to fashionable, pretty, or anything else except a standard for checking fit: Are the seams where they should be and straight? Do the neckline and waistline land where they should? Does the garment fit smoothly without wrinkles? Can you move and sit down without straining the seams?
For fitting pants, the slacks draft is the basic pattern--no frills, just darts and a smooth fit to make up in a fabric to check fit, feel, movement and comfort. In Curves, the basic patterns are the bra, knit top, pants, and leotard. All other designs are developed from these basic patterns. Okay, some more background: There are three basic methods to patternmaking: Drafting, Flat-pattern, and Draping.
DRAFTING is creating pattern shapes from measurements. You have DRAFTED a pattern if you have ever made a pattern piece from measurements, such as a gathered skirt which is made from a rectangle the length you want it plus seam allowance and hem allowance by the measurement of your hips times the desired fullness.
Flat-pattern designing uses a sloper (or paper pattern) and the desired changes are made by slashing and spreading or redrawing shapes. You have used flat-pattern techniques if you have ever changed a neckline, shortened a sleeve, rotated a dart, etc in the pattern paper before cutting the garment out.
Draping is a method of cutting and folding shapes and pinning the fabric to a dress form. You have draped when you have made changes in the shape upon trying the garment on--pin fitting, adding darts, tucks or pleats, changing a dart to a tuck, etc. There, I bet you didn't know you were so smart!
Now technically, PMB uses the pattern drafting method. Lisa has programmed in formulas to create pattern shapes from YOUR measurements, thus letting the computer do what it does best--MATH calculations! The directions for measuring the body are somewhat universal and somewhat specific to PMB, which is why they must be as accurate as possible.
So, instead of using a commercial basic pattern and altering it, we use PMB to make our basic pattern from our own measurements. Then, once we are comfortable that the basic fitting shell is satisfactory, we can be somewhat confident about drafting other styles. Back to what is a SLOPER and why are we using this term incorrectly?
You see your own personal SLOPER (or foundation block) as a red outline on the computer screen when you have that choice selected--and it has no darts or seam allowances, right? And no matter how you start, you take the first paper pattern created or purchased and use MUSLIN (traditionally) or other fabric to check the fit. Since "muslin" is used for both the fabric and the fitting garment, I prefer to call this a fitting shell (toile in some countries and the industry) and save SLOPER for the no seam or dart allowance pattern used in flat patternmaking and MUSLIN for the fabric used.
By the way, I just looked in the PMB table of contents, and they also refer to trial garment as the FITTING SHELL. My quick glance through did not find sloper used for the fitting garment. The Curves book also refers to fitting garments and fitting shells, but then starts using "sloper" to refer to the basic pattern block AND sometimes it seems to refer to the fitting garment. But overall, WG is following the naming conventions as I learned them.
SO--I would say that this group is using SLOPER for the FITTING SHELL at least part of the time. But it would be less confusing if we stuck to: