More Skirt Math, part 1

This is the new skirt (minus pockets, because I barely understand them, and have no idea how to explain, much less illustrate how they work):

The skirt is made up of 9 pieces: 7 trapezoids for the top of the skirt (4 in front, 3 in back) and two rectangles for the bottom (one front, one back), plus the waistband, which I am in the process of redesigning, more on that later.  This construction serves two functions: makes it easier to put in a zippered fly, and creates the hip shaping. 

NOTE: Because of the zippered fly, there will be a slight difference between the right and left sides of the front of the skirt.  I will be referring to R and L sides from the perspective of when you are wearing the skirt.  Stage Right and Stage Left, if you will.  Like this:

I do it this way because whenever I get confused I usually look down at what I'm wearing and think, okay, so this goes here.  Also keep in mind that this diagram is the way the skirt will look when finished, so the right sides of the fabric are facing.  If the skirt is wrong side facing, the R/L will be reversed.  Yay!  This is seriously the worst part of this whole thing.

Okay, so getting started.  The front of the skirt is made out of 5 pieces, shaped like this:

Math: Measure your waist at approximately 2" below where you want the top of the skirt to be.  Measure the widest point of your hips.  If you are like me, and have hips that are the same size as your waist, you can use the diameter that you would like your hips to be.

The 0.5" you are adding to both measurements is for a .25" seam allowance (one on each side).  If you make larger seams, you will need to add more.  The last skirt didn't really care about seams because most of the skirt wasn't fitted, and besides, there was elastic.  This skirt is fitted, and has no elastic, so it needs to be a lot more fiddly.  Be prepared to try on, tweak, and repeat.

Measure the distance between your waist and the widest part of your hips (or, like me, where the widest part should be).  Add 0.5 for seam allowances, and this is measurement C.

If you want to do an invisible zipper somewhere, you can skip the next part, and make one center panel with the same measurements as the sides (A on the top, B on the bottom, C tall) but center the top so it goes out equally on both sides.  Otherwise, follow along:

Are we good?  The rest is easier.  H is your hips plus .5 seam allowance.  I is the total length of your skirt minus C.  (True, you will lose some length with seams, but you will also gain some length with the waistband, and ta-daaa they cancel each other out!)  If you are working with fabric that will not fit a single piece that is H by I dimensions, as long as you can piece something together that ends up at H by I, you'll be fine.  If you are piecing, I recommend splitting the width in three pieces or five, or some other odd number.  It just looks better.

STEP ONE: Now that you have your dimensions, you can cut out your pieces!  Remember that each piece has one side that is square, and one side that is angled.  The easiest way to do this is to make a rectangle, and then trim in on one side to the smaller dimension.  If you are working with a light fabric, you will also want to use interfacing.  I really, really, like a heavy woven iron-on interfacing, but there are options, and you might like something else better.

It is always a good idea to actually write all of these things down, so you end up with a diagram of each piece.  It might also be a good idea to draw/cut pattern pieces out of paper or newspaper, and write on each piece what it is.  Once you cut each piece in fabric, pin a label or write in sewing marker so each piece is clearly labeled.

TO BE CONTINUED.