How to scan an object to scale?

Yes it is nice to be able to put your projects INSIDE something isn't it? You know, to hold everything together so it doesn't flop around? Discuss the techniques here!

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woox
Posts: 129
Joined: Sun May 11, 2008 9:15 pm

How to scan an object to scale?

Post by woox » Fri Mar 12, 2010 1:29 pm

Hi

First off I amtrying to create a create an accurate scan of a flexible keyboard and create slots for the keyboard for a 360 laptop

Basically I am trying to create slot/holes for proper keys for the TAB, SPACE, ESC, ALT, CNTRL, (QWERTY KEYS).

I want to SCAN the image in from a scanner and just draw boxes around it in Adobe Illustrator and have the CNC go cut the right sizes out, but when ever I try to scan I can never scan it to the proper scale of the actual item, its always huge and really high res ( i tried lowering it).

How can I scan a image to scale (scale meaning the size of it in reallife). A 0.5x0.5 " key would scan to like 3"x3"

Any idea or help?

Timthegeek
Posts: 20
Joined: Thu Apr 01, 2010 12:54 pm

Re: How to scan an object to scale?

Post by Timthegeek » Sun Apr 04, 2010 10:46 pm

The short answer.. Lay a ruler next to your object to scan.
The long one.. You then have the required reference to scale. Cnc might need a cad based file so whatever you scan will need to be vectorized. Difference from a raster image produced by a scanner (dots per inch) and a vector drawing (which illustrator should do) they are points and lines. I could scan, import into cad, scale, and trace a keyboard layout, then dxf for any cnc process, in about 1/2 hr.

Gimmie a hollar if u need any help, heck email me the scan (with ruler) and I'll do it fo free.

Timthegeek
Posts: 20
Joined: Thu Apr 01, 2010 12:54 pm

Re: How to scan an object to scale?

Post by Timthegeek » Sun Apr 04, 2010 10:58 pm

Sorry, I realized I didn't answer your exact question.

Sounds like you have dpi issues.
Scanners are highres 300-2400dpi
Screens are somewhere around 70ish up to 100ish
illustrator has a setting for the file you are working with
if your scan is 6 x the actual size it is possible that the scan is 1200dpi and the file is 200dpi thus causing the scan to scale upon import.

both the scanner and file have settings confirm they match

also note that screens/monitors are never actual size even when zoom is 100%
and printers need some calibration when printing exact scale
cad plotter software or drivers most all have a setup.

Print a 3x3 square and measure it, this will confirm the printer isn't skewing the aspect

hope that helps

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