Obviously they firstly needed to be very light, reasonably robust and BIG. Anyway, here's the image I was given:
So the materials used:
Polyurethane packing foam. This is very light, easy to cut with a craft knife or box cutter. It's soft enough to be reasonably comfortable for the model and most importantly it is reasonably stiff. It will be used for the main 'spars', so if you are using some other material, the test is simple. Cut a four foot length 1" square, hold it by one end and see how much the other end droops. It it only droops by one or two inches then it should be fine for this job.
Black Organza Voile. A very lightweight 'shimmery' mesh fabric for the membranes. You could use any one of the hundreds of colours available.
Liquid Latex. Used as a strengthening skin for part of the spars and to glue the fabric to the spars
General purpose adhesive. Bostik, UHU or a similar adhesive that can be used as a contact cement.
Paint. I used artists acrylic inks for this job which were airbrushed on, but any sort of hobby acrylics would do just as well.
Before continuing with the next set of steps I must apologize for my state of undress in some of the images. It was the middle of a heatwave and unbearably hot in the workshop!
Step 1: Constructing the spars
Using as much of the width as I could I cut two curved 'bone' shapes about 2 1/2 feet long to form the two upright curved spars.
I then cut two four foot curved and tapered lengths to form the main outer spars. These were joined to the uprights using general purpose adhesive using the impact method and pinned through with cocktail sticks.
Once the two main structures were glued I cut four smaller lengths of foam for the inner spars. Again these were cemented into place and pinned with cocktail sticks.
The two assemblies were then given 24 hours to fully cure.