Alison Friedlander

Blog

The Dangers of Distortion

The Images:

  • The reference photo I used to model the ear piece for my roommates glasses
  • The model itself over the reference image (I even elongated the back to theoretically account for the curve of the glasses)
  • How terribly off the model was (short piece was first iteration, long piece is final) 

So what the heck happened?!

In a nut shell – I took the picture of the glasses at an angle and it was distorted. This, coupled with the bend at the bottom of the glasses being more extreme than I’d expected, meant that the ear piece was about 1mm short near the lenses/hinges and 15-20mm short where it was supposed to sit on the ear.

Had I not stopped the first print half way through (I realized I made the piece for the wrong side of his head) and tested it against the original glasses, I would have kept plodding along and wasted time and [more] plastic.

 

What can you do to prevent this?

If you’re going to be modeling directly off an image, you can ideally scan the object, which will ensure it’s flat and there’s no distortion from holding a phone at the wrong angle. If that’s not an option, just try to get the camera as straight as possible and double check more than a single measurement to ensure there’s little-no distortion in the piece.

When I was working on this, I…

  1. Took the reference picture
  2. Measured the widest part in the ear piece on the actual glasses (where I put the “YO”; it came out to about 9mm)
  3. Scaled the drawing up in my modeling software so that the area I measured was 9mm
  4. Models the rest of the piece.

Had I bothered to measure and verify the length of the ear piece, I would have realized the reference image was really off and compensated earlier.

It ended up working out in the end, but if this were a giant piece that used 200g of plastic instead of 2g, I would have been pretty irritated if I’d let it print the whole way through and then found out it was the wrong size.