2025-02-05

Last modified: 2025-02-09 15:14:56

Rubbing car

We've been around the Haynes Motor Museum again today. They have these copper plates with cars engraved in them, and you're meant to hold a piece of paper on and rub a pencil over it and it makes an image of the car.

Emma asked if we could 3d print some, so I'm having a go.

I started with this photgraph of an MG Midget I found online:

And lasso-selected it in gimp, edge-detected, and manually touched-up edge detection imperfections:

Then used https://3dp.rocks/lithophane/ to make it into a 3d model. I could have used OpenSCAD but I recall OpenSCAD is very slow at this sort of thing.

Then print it with the pattern facing downwards so that the "raised" section is very smooth from being against the build plate.

And failing 3d printing we could always use Meshmill to engrave it in a piece of aluminium.

Not great, I think the lines are too thin, but it does basically work.