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What cheap setup or technique works for truly flat photos for use in CAD? (lemmy.world)

submitted 5 days ago by j4k3@lemmy.world to c/asklemmy@lemmy.world

22 comments fedilink hide all child comments

I've managed to do reverse engineering of circuit boards using GIMP and rough alignment of layers using images like the one pictured. I want to use images to reverse engineer parts in CAD, but the minor lens distortion of a camera on a phone at ~20cm high on top of a stack of objects to keep it eyeballed flat is not enough. The result is off in multiple planes. There are minor errors in my curves in the transparent CAD part pictured, but the hole pattern is correct. The picture has been calibrated to 20mm against the ruler. Any suggestions on how to make this usable for replicating the ellipse that crosses the holes ±0.05mm?

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[–] Uranium_Green@sh.itjust.works 12 points 5 days ago (1 children)

Do you have a flatbed scanner? Like a photocopier printer?

Literally put the item on the glass of the flatbed and hit scan, stick an etched mm ruler beside it facing the scanner if you want scale.

It's generally the most effective way by far to perform this.

I've used it to copy the perfect profile of an extruded aluminium ebike battery housing, to print a replacement cap after the first got cracked.

Basically when you try to use your phone to perform a task like this, you'll need to account for the inherent lens distortion of your camera, which is a pain in the ass

[–] Botzo@lemmy.world 4 points 4 days ago

A decent laser etched steel carpenter's square should run you $10-15 and give you 2 dimensions!