Hurricane Cape

Jamie as the Hurricane Queen at Theatre Bizarre 2014

Jamie made a pretty kick-ass cape for Halloween 2014, when she was the Hurricane Queen. It uses lots of math and laser-cut fabric!

Cape Pattern

I made the cape pattern using a combination of trial and error and math/geometry. I cut prototypes out of Swedish tracing paper on the laser cutter. Swedish Tracing Paper Is thin paper that doesn't tear easily and drapes more like fabric than regular paper, good for mocking up sewing patterns.

I started with the width that I wanted the cape to be around my neck (22"), and made a quarter circle-based shape that would be 50" long, which for me is about the length from my shoulders to the floor. I wanted it to be almost floor length for maximum drama, but not dragging on the floor. I also made a high dramatic collar that was 22" across at the base to match up with the top of the cape. I had to cut mantle pieces separate from the main wedges in order to fit the main pieces onto the laser cutter bed. The laser cutter didn't like being used at its full 36"x48" theoretical bed size, so I scaled it down a little until the laser was happy. Happy lasers are productive lasers!

Note on Pattern Pieces and Seam Allowances

Sewing patterns require seam allowances to be sewn together. If you're using illustrator to make pattern pieces from an initial overall shape, it's actually pretty easy. Use the Pathfinder -> Divide function to divide the design into pattern pieces, and Object -> Path -> Offset Path to add a seam allowance (usually 1/4" to 1/2"). I assume there are similar functions in Inkscape. I always do the seam allowances last.

Note on Dimensioning in Illustrator vs. Inkscape

A lot of people use Inkscape for vector graphic design, and the main reason that I don't is that Inkscape is crazy frustrating when it comes to accurately dimensioning parts. Illustrator is by no means CAD, but Illustrator will always measure dimensions from the true center of a stroke, while Inkscape for some unfathomably retarded reason, will change dimensions if you change the stroke width of the path. Since the stroke width does not matter at all to the laser, dimensions measured in Inkscape are utterly useless for laser-cutting, unless you're ok with working with invisible zero-width strokes (which I am NOT).

Mathematica Code

I modeled hurricanes using a combination of sink flows and vortex flows (combination of sucking inward and spinning around, as a hurricane does). I used equations from this helpful PDF on modeling hurricanes. I made a function in Mathematica to parametrize the hurricane model in terms of q (magnitude of the sink part), k (magnitude of the vortex part), cx, and cy (coordinates of the center of the hurricane. I used the function "Streamplot" to plot the streamlines of 6 hurricanes interacting with each other. (Some of the hurricanes are terrifyingly non-physical hurricanes that would spew outwards at alarming rates, but....they looked pretty!) I came up with the parameters for the hurricanes by an addicting series of trial-and-error.

Streamline plot of hurricanes from the code below

Hurricane[q_, k_, cx_, cy_] := -1/((x - cx)^2 + (y - cy)^2)*{q (x - cx) + 3 k (y - cy), q (y - cy) - k (x - cx)};

StreamPlot[
 Hurricane[1, 1, -1, -2] + Hurricane[1, 1, 1, 2]
  + Hurricane[-2, -2, 3, -1] + Hurricane[2, 2, 3, 1]
  + Hurricane[0.5, -1, 7, 1.5] + Hurricane[-0.5, -1, 7, -2],
 {x, -3, 9}, {y, -3, 3},
 StreamPoints -> Fine,
 StreamStyle -> "Line",
 AspectRatio -> .5
 ]

Streamline Design in Illustrator

Outline of cape with streamlines directly exported from Mathematica overlaid

Added extensions to cover the whole shape of the cape and did general art-ing on the pattern to make it even prettier.

Cut off the lines outside the cape outline and added a swoopy shape to the stroke (Hurricanes have to be extra swoopy, obviously). In illustrator, I use Pathfinder > Outline to crop strokes, and Offset Path to make a dummy cape outline that's smaller than the real cape, in order to have a margin. I made the swwopy shaped strokes by changing the stroke profile to one of the preset options that tapers on both ends. Normally I wouldn't do anything to the stroke profile for lasering, but in this case I was going to actually cut out the outlines of the strokes, not just along the center of the original strokes.

Turned the strokes into outlines for lasercutting (Expand Stroke), separated the cape into 3 panels that fit onto the laser-cutter bed, and added seam allowances (1/4") and hem allowance at the bottom (1/2"). To do this I used a combination of the Cut tool and Offset Path. I made one version of the cape outline with 1/2" extra and one with 1/4" extra, used the Cut tool to separate the bottom edge from the rest of the cape on both and joined the segments I wanted to keep.

(Remind Jamie to upload the laserable design files here)

Construction

I used 3 fabrics and an interfacing for the cape.

1. Navy blue velvet for the outer layer that contains the streamline design. I cut 2 collar pieces, 3 mantle pieces, and 3 main pieces. Later I remembered to cut a couple of strips to make a loop to attach a chain to, to go around my neck.
2. Aqua polyester (semi-shiny, probably from the formal wear section) for the contrasting background of the streamlines. I didn't lasercut this layer at all due to construction reasons (see below)
3. Light blue swirly-patterned satin for the lining. I just used the outlines of the cape pieces from the velvet patterns. I cut 3 mantle pieces, 3 main pieces, and 2 pieces for a pocket.
4. Sew-in interfacing for the collar. 1 collar piece. I used a pretty stiff woven interfacing because i was worried about the collar flopping, but it ended up being too stiff, so I'd use a lighter one next time.

Laser cutting

You should iron the lining first to get rid of creases, and if you're feeling daring, try lightly steaming the velvet. Look to the rest of the internet for advice on ironing velvet, not me. My velvet wasn't creased or wrinkly since i'd just bought it, so i got away with not ironing it. If you have something big that you can reliably move the fabric around on, use that to layout the fabric, otherwise place it face-down on the bed. (If there's char, it'll be on the top side of the piece being cut, so make the top side the wrong side of the fabric to be safe.) Make sure the grainlines are square with the bed. Fabric in general is pretty easy to cut, even the velvet. My default laser settings for "soft" things like fabric and leather are Speed 50, Power 50, but I might have sped it up for the streamlines because they took a while. The main velvet pieces generated machine code files too big to transfer over the USB cord, so I had to put them each on a flash drive and download it directly to the laser cutter. I may have said more smart things about cutting fabric on Sewing Patterns on the Laser Cutter

(Remind Jamie to post one of the pictures/videos of the velvet and lining being cut here)

Attaching the velvet and backing

The first thing I had to do was combine the aqua fabric backing with the velvet outer layer with the design. The hardest part about this is that the velvet with the design was incredibly hard to deal with. With all of the cutouts, it had no structure and just sagged into a sad tangled heap. I used spray-on adhesive to combine the 2 fabrics. It's fabric safe and worked decently well, although the resulting fabric was pretty stiff. Here are the steps i went through to glue the pieces together.

1. Cut the backing fabric into a rectangle a little wider than the widest part of the cape piece and a little longer. You want to be conservative with this, add at least a few inches in each dimension.
2. Lay out the backing fabric rectangle on a large table with the right side facing down.
3. Get a wrapping paper tube or poster tube and roll the backing fabric onto the tube. The right side should be facing out.
4. Practice rolling and unrolling the backing fabric several times to make sure you can do it straight and without any creases.
5. Cover the table with something disposable, like butcher paper. It's going to get glue on it.
6. Use one of the lining pieces or a piece of cardboard that's cut to the piece size to make a Sharpie/pencil outline of the piece on thebutcher paper.
7. Put the sad heap of velvet on the butcher paper right side down.
8. Spend a long time arranging it so that the pattern is correct and not getting tangled up in itself. You'll see why the outline is helpful - the velvet has so little structure that it doesn't even know where its outer boundaries are.
9. Spray the velvet with glue and wait for 30 seconds or so for it to tack up. You want to be pretty thorough with this, but don't spray so much that the glue puddles up or looks opaque white. Fabric absorbs more glue than, say, wood, and different fabrics absorb different amounts. You should probably practice with a scrap piece of velvet first to get a feel for how much glue is enough, but not too much. You want to spray from pretty far away and do multiple light coats. This is true for every spray application,but is especially important for fabric because you don't want the force of the spray to make the fabric shift even a little. Once there's glue on it, you really can't touch it without making it worse.
10. Put the tube with the backing fabric at the bottom of the cape. (The bottom is the widest point, and it's better to do the widest part first in case the fabric goes crooked later.) Allow a few inches before the cape starts to get the fabric rolling
11. Carefully roll the backing fabric up the piece. Try to only apply downward pressure, not forward pressure. Let the rolling happen naturally. The goal is to have the fabric roll straight up the cape so that the grainlines are aligned. The extra couple inches on the sides is helpful if it starts going a little bit crooked. Try to avoid creases. If the fabric starts going crooked, don't try to fix it, you'll just make a crease and that'll look worse than a slightly stretched fabric. The fabric i used was woven, and I would imagine this would be much harder with a knit. Maybe not impossible if you're careful, but harder.
12. Press down gently only on the parts with velvet underneath. If you press down everywhere, the backing fabric might get glue on it. This isn't the end of the world if you're careful, but it does gunk up the fabric and make it a little harder to unpeel later. Make sure to press thoroughly on all the edges.
13. As soon as you've pressed it toegether with your hands, you'll want to move the whole piece to another surface - before the glue has fully set. This is so that if you did get glue on the backing fabric, you'll be able to unpeel it before everything is stuck together stronger. At this point the fabric should be bonded enough that it'll stay together. However, you'll probably want a helper. Start from the top (the smallest part, easiest to unpeel), have one person be in charge of holding the fabric and one person in charge of making sure that the pattern comes off the table cleanly. Use your hand to gently work any stuck pieces off of the table. The fabric will peel off and end up hanging vertically from one person's hands.
14. Because the glue hasn't set fully, have the other person grab the bottom and move the piece to another surface, and set it down right side up.
15. Wait for the glue to set up based on the package instructions, probably about a day to be safe.
16. Use an exacto knife or scissors to cut the backing fabric to the outline of the velvet layer.

That seems like a lot of steps, but other than arranging the sad tangled velvet heap, it's not that bad once you get the hang of it.

(Remind Jamie to post pictures of laying out, gluing, and rolling here)

Sewing

This is a pretty straightforward process if you're at all familiar with sewing, since the actual garment design is pretty simple. I'm writing this a while after the fact, so I don't remember all of the details, but just look at any other cape or garment sewing instructions.

1. Iron all the pieces as best you can, just like for laser-cutting. Press the seams in between each step.
2. Lining fabric: sew 3 mantle pieces together
3. Lining fabric: sew 3 main pieces together
4. Lining fabric: sew the mantle to main piece, being careful to align the seams.
5. Lining fabric: sew 3 sides of the pocket together
6. Velvet: sew 3 mantle pieces together
7. Velvet/backing: Sew 3 main pieces together, being really careful to make sure the pattern aligns.
8. Velvet: Sew the mantle to the main piece, being careful to align the seams.
9. Collar: I think I sewed the interfacing to one piece, then sewed the wrong sides together. I might have done it in one step. Keep the bottom side open so you can turn it right side out. I had a lot of problems with this because of the really stiff interfacing. I maybe should have cut the interfacing a little smaller to help ease it into the fabric. I didn't really look at how this kind of thing was usually done before making up my pattern.
10. Sew the top edge together. This includes the collar, lining, and velvet. It's a thick sandwich.
11. Make fabric loops and loop them around D rings or cut ribbons for the neck tie and make sure you place those when sewing up the sides.
12. Sew one side together
13. Insert the pocket on the other side while sewing the side together. Ask the rest of the internet for details on adding pockets along a seam, not me.
14. Turn everything right side out
15. Fold the velvet over the lining at the bottom a little and hem it. I may have added a little more length to the velvet piece for this, or I may have fudged it. Halloween costumes are great for fudging. Again, ask the internet for how to properly do this.
16. If you're using chain as the neck fastening, attach that and a clasp to one of the D-rings using jump rings and pliers.

Lessons learned

• The pattern would have been easier to align with bigger seam allowances, I think (I only used 1/4").
• I could have left wider margins around the design to make the fabric pieces a little easier to deal with.
• The mantle pieces draped differently from the main pieces because they didn't have the backing. If i did it again I would glue the backing fabric to the mantle pieces as well to make them all drape the same.
• As i said earlier, the interfacing was too stiff and bulky.
• I drastically underestimated the size of the pocket I'd need. Make your pockets bigger than you think you'll need. Also be sure to really stitch them securely because those seams will be under more stress than the rest of the cape (at least if you have a heavy cell phone)
• Velvet is expensive. I don't know if I would really do anything differently next time because velvet is also super cool, but I had to toss one laser-cut piece when I failed at gluing it right and had to buy more fabric... I probably spent ~$80 on fabric for this.