[Taark]

Hey Everyone,

Just looking to see what techniques people use to measure an item and reproduce it in CAD.

The 2 ways I use are:

Trace 2D surfaces onto paper, scan and use a 2D program to sketch around it (not very accurate...)

Or

Grab my trusty verniers, pick a reference point and get measuring. This can be quiet time consuming...


What other options have I got?

Regards,
Tarrick

[daniellyall]

laser scanner there are some cheap option that work quite well well 1 out of 20 I tried anyway, or tormach camera scanner program

[Taark]

How accurate are they?

I use standard engine parts, copy the bolt patterns etc and re-design the parts to be machined in billet aluminum...

[FredSWUG]

Sometimes you can skip the tracing step and simply put the part on a flatbed scanner.
Laser scanning is great, but time consuming. The accuracy will be a function of how much the scanner and the associated software costs.
You could also take orthographic photos of the part, scale them, and use those as a basis for your sketches.
And my personal favorite low tech method involves taping a scale to the monitor to get a 1:1 sketch, and then holding the part against the monitor while sketching around it. I'll admit that it is not pretty or precise, but if the goal is to duplicate a curvy profile, it works quite well.
I also convert a lot of photos and sketches of parts to DXF files with Vector Magic. I can then import a DXF file, scale it, and start building a model.

[warrenb]

Well. There's laser scanning which I have found pretty useless for mechanical shapes. There's laser tracking which is good for large objects with generous tolerances. There are desktop digitizers like my Microscribe which is a fantastic gizmo but not super accurate. There is the trace 2D which is great, cheap and easy. Then there is the very accurate CNC CMM. It depends on your budget and requirements. For SW I trust my calipers and measuring devices. You can import 3D excel points but I prefer processing them in ZW3D or Rhino3D then exporting the point cloud to SW. SW does not work well with 3D point clouds even though there is the option. SW does work well with 2D point clouds to define sketches.

[awerby]

With good scanning hardware (like the Capture structured light scanner from 3DS) and reverse-engineering software (like Geomagic Design-X) you can do feature recognition and retrieve design intent to produce an accurate CAD model that will import into SW. You still need to check measurements here and there, but you get very close and tweak it to right on. This only works for parts that are visible, though - for internal volumes you can't get a line of sight into, the only automatic way to image them is with a CT scanner.

[deadlykitten]

i saw a movie with Jackie Chan using some nice gloves ..."The Spy Next Door" ? i am not sure