In this 3DShoemaker post, I’m going to explain how the newly available shoe last outlines can be used to help with online shoe sizing. This will be useful for both shoe businesses and individual shoemakers, including those 3D printing the entirety of the shoe. And for those using the 3DShoeamaker design software, I’ll show how to create the shoe last outlines.
The world of shoe sizing is a bit of a mess, to put it lightly. Not only are there contradictory definitions of the numerous shoe sizing systems, but just about every company out there seems to have a different opinion on what the underlying measurements of the various sizes should be. Things get particularly murky for niche types of footwear, like climbing shoes and ice skates. This wasn’t too problematic back when shoes were bought exclusively in brick and mortar stores. It was standard practice to try before you buy. But with the rise of online shoe shopping, customers are mostly in the dark. And it is inevitably the customer that bears the brunt of the cost, whether directly through return shipping or indirectly through higher priced footwear.
One solution that has been promised for a long time now is digital fitting. A customer gets their feet scanned, either by using their own smart phone or as a one-time service in a store, and then the resulting 3D models can be used to find good fitting footwear. But this just hasn’t materialized to any particular degree of success. Smart phone scanning has been too awkward and error prone and shoe stores using scanners don’t share the resulting foot data. Perhaps the bigger issue is the disconnect between shoe retailers and overseas manufacturers. By the time the shoe gets into the warehouse, knowledge of the core inner geometry of the shoe, as dictated by the shoe last, has been lost. By using 3DShoemaker models, both businesses and individuals are better served. The underlying shoe last geometry data is transparent and readily available to improve online sizing. And, uniquely, flattened outlines are now available in all sizes and widths for end users to print out and use for reference. Additionally, for those using the 3DShoemaker design software, flattened outlines can be created easily for any parametric shoe last design.
I’ll start by pointing out that shoe last outlines are distinctly different from the flattened insole patterns I introduced a while back. The insole pattern coincides with the last bottom edge, AKA the feather edge. Insole patterns are useful to shoemakers and perhaps can be helpful in shoe sizing, but they don’t tell the whole story. This is because the shoe last overhangs beyond the bottom edge both at the front and the back of the shoe last, and the degree of this overhang varies from one shoe last to another. The same can be said for heel and ball width. The shoe last outline, on the other hand, gives a more complete picture of the envelope into which the foot is to fit. One nuance I should point out is that insole patterns are flattened in all directions, removing the roll on the bottom of the shoe last, whereas outlines are essentially just unrolled along the shoe last length, removing heel height and toe spring to give the true length of the last.
All outlines for 3DShoemaker shoe lasts in PDF format can be found here. They should be printed at 100% scale and the specified dimensions should be double checked after printing to verify proper scaling. Then the paper should be cut at the back line so that it can be butted up against a wall. Then the paper can be stood on, with the back of the heel touching the wall. Ideally the entirety of the foot should fit in the outline and there should be ample toe allowance for all toes. This allowance is usually something around 15mm for an average size, less for small sizes and more for larger sizes, but can vary for different types of footwear. If the fit doesn’t appear good enough, simply print a new size and/or width and try again.
One other thing to check for is that the ball line of the foot should match up with that of the shoe last. If it doesn’t match up, the solution is customized adjustments, which is something I’ll cover in an upcoming video. I’ll also get more into girths, instep heights, and the plantar shape of the foot too.
If you are using the 3DShoemaker plugin for Rhino 3D, you can create your own shoe last outlines by pressing the Make button and then the Go button on the Flatten tab. This is also how insole patterns and flattened medial and lateral sides of the shoe last get created.
Using shoe last outlines for shoe sizing is not the perfect solution. The fact is that both the foot and the shoe last are organic 3D shapes and their relative fit is extremely complex. And it’s more than just a geometry problem. One also has to consider the properties of the foot, the intended use of the shoe, and the fit preferences of the individual. But using outlines gets us most of the way there and is considerably better than using just linear measurements.
So whether you are a shoe brand looking for shoe lasts to manufacture on, or you are an individual hobbyist shoemaker trying to decide what shoe last or shoe model size to buy, I suggest making use of the 3DShoemaker shoe last outlines. Also, if you are looking for the next level of fit testing, you might check out my recent post on 3D printable shoe mockups. This is particularly useful for those doing bespoke and orthopedic shoemaking.
