Testing out how a 3D printed edge edge with stitching holes could work to stitch on an upper. The edge also has an attached heel cup and toe box.
Making and attaching the upper.
The 3D printed edge creates a clean lining, maybe this shoe be on the outside of the upper. The heel and toe lining work well and could be thicker but there is also a possibility to stitch the upper onto these parts too. The upper is still difficult to measure and not get any pulling or folding, maybe it would be worthwhile trying to use a last of finding open source stamps.