It has been a long time since my last post on 3D printed insoles or indeed any other subject, but there is good reason.

Over the past year I have taken all I know (insert joke here) on designing and 3D printing insoles and packaged that up into a mostly all-in-one piece of software called Gensole®​.

What is Gensole?

Gensole is a browser based tool which allows you to design insoles, optimised for 3D printing using the FDM process and Filaflex (TPE/TPU) type materials. It will ultimately export .AMF files for importing into Slic3r for 3D printer toolpath creation.

It is free for makers, and researchers for non-commercial use :

...Continued from Part 3 - Variable Density Insole

Now it gets interesting. This post concentrates on the scanned data and image manipulation using Gimp, Inkscape and OpenSCAD, all of which are free and open source. However if further refinement of the 3D formed surface is required then Meshmixer is a great free tool (not opensource) for smoothing or twisting and pushing/pulling the mesh around.

I will show how to scan your foot and turn this into the CAD data used in the previous variable density insole to define the density zones, and also to create the surface data to fit the form of the sole of your foot. The form fitting surface is actually the easy part due to the new great import option in OpenSCAD which build a height map according to the brightness values in an imported digital photo. With a foot scanned on a simple document scanner the areas of the foot that are close to the scanning head, the brighter the image. The areas that are further away are darker. When the surface is built, the darker areas are thicker and the lighter areas are thinner, making a surface as shown :

The saying, "You cannot push on a rope" remains as apt as ever when it comes to 3D printing with flexible filaments. Most printers will have some form of success straight out of the box with flexible filaments, but don't be greedy to begin with, turn the printing speed right down. Within this article I will try to explain as best as I can the problems, pitfalls to avoid and how to achieve success with pushing on a rope to achieve good print quality at acceptable speeds, in this case substituting the rope for flexible and elastic filaments for 3D printing such as Filaflex.

A flexible filament is generally a Polyurethane or Co-Polyester (not exclusively) Thermoplastic Elastomer (TPE) with a complex mix of additives/colourants to aid the 3D printing process. With good elastic properties and high co-efficient of friction means 3D printed designs in this filament expand the design possibilities. Effectively it is a soft stretchy grippy material.