After reading RoxyRoo's post about using the hex pattern from a heat resistant pad to imprint the hexagon pattern on the undersuit
http://www.405th.com/showthread.php?t=45223&page=2 that got me thinking about the hex pattern infill in Slic3r. All you'll need to do is design a short box with a large enough length and width to use (but smaller than your print bed).
When you use Slic3r, in your print settings;
1. Layers and Perimeters- a. Perimeters = 0
b. Horizontal shells, Bottom = (however many you want to hold it rigid) Top = 0 (This will be the contact area)
2. Infill- a. Fill pattern = Honeycomb
b. Fill Density = (User preference). The fill density is a percentage between 0% and 100%. You won't be able to go up to 100 (it won't let you. this would be a solid infill). Setting the percentage determines the size of the hexagons. 10% would be larger hexagons and 90% would be smaller. Experiment using a smaller box file to conserve plastic and compare and test for your desired look.
c. Under the advanced setting, ensure the "Solid infill every:" is set to "0".
3. "Support material" is turned off.
4. Since you will be using heat on your material, I would suggest printing with ABS or any higher temp material. PLA wouldn't be recommended since it has such a low melting temp and can deform easily.