These are 3D printed Flip Flops in UK size 7. Luckily I have small feet (for a guy) and these should JUST fit on a Prusa print bed diagonally. I have been wearing these for all of last summer with no major issues and they they are very comfortable.
THE STRAP IS SOFT AND FLEXIBLE. I personally find Flip Flops that have a rigid 'pillar' between the toes to be uncomfortable - so I have designed the strap to be of the soft flexible type. TPU is a super strong material so even though the strap is 0.4mm thick - its virtually 'un-snap-able'! I think you will find my design is pretty much unique on the web in this regard.
The STL files you need don't show up in the preview for some reason, but they are all there in the file list. The files have all been checked using the online Netfabb repair service so should print with no problems.
If you want to adjust the softness of the soles, then simply use a less tha 10% infill. I have designed the 'heel' part of the sole to be slightly firmer than the rest of the sole, as this is the part of the sole that takes most of your body weight.
If you want the nice textured surface on the top of the soles/strap (rather than smooth), this is achieved by using a textured print bed - these are available from Prusa and are a bit more expensive, but are worth the investment I think. These beds are available for some other types of printers as well.
You may have noticed that the strap is only 0.4 (ie. 2 layers thick) - don't worry, TPU is an INCREDIBLY strong material - even the cheaper brands should be fine for these - as long as you know how to print TPU and are familiar with the best settings for this material with whatever printer you are using. For best results, dry your TPU filament out at around 55 degrees C in an oven or a modified food dessicator etc. for a few hours first.
TIP FOR SUCCESSFUL PRINTING WITH TPU - Some people have the problem of TPU filament spilling out the side of their extruder like spaghetti when printing. I have found (with the PRUSA anyway) that by LOOSENING the two tension bolts for the gears on your extruder by ONE TURN (from a normal PLA/PETG setting) using the Allen key - this problem goes away.
BEFORE YOU ASK... if you have different sized feet to me, you will have to figure this out for yourself I'm afraid. TIP - get the dimensions from an existing Flip Flop/Sandle you have and scale everything accordingly. Good luck!
PLEASE FEEL FREE to ask me any questions on assembling these, unfortunately my connection dropped out when I was typing them - it's quite straightforward, just use the pliers shown in the pic to pull the strap tabs through the holes in the soles and push them back in. NO GLUE NEEDED - the tabs are designed to stay in the slots with friction alone.
The side parts of the strap can actually be threaded through the slots easily (unfolded) without the pliers, THEN fold over the tabs and tuck back in the underside slots firmly.
LOOK CLOSELY at the (View original) photo - the 'toe' strap tabs need to be folded in half FIRST (with the fold facing backwards), then poke the nose of the pliers through the hole (its tight, but the hole should stretch without damage) - then grip the folded tab and PULL FIRMLY through to the other side and tuck into the slot. Enjoy they work well.
Print the soles 'upside down' ie. with the tread facing upwards and the flat top surface against the print bed.