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How to get a complex tubular object into CAD? 1

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luke1201

Automotive
Mar 16, 2005
15
I have some complex pieces of tubing that I would like to get into CAD so that I can get quotes on getting it reproduced. I know there is some method or device, where they take something like a v-shaped wand, index it to a known starting point (x,y,z), then drag the v-shaped wand (straddling the tubing) down the tube and *poof* it appears in a CAD program.

What is this device/technology/service called?

Thanks.
 
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I would call it 3D part scanning/digitizing. If you plug that into Google you get some good hits. Here is one that caught my attention


This type of technology is currently employed in automated inspection.

Best Regards,

Heckler
Sr. Mechanical Engineer
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Do you trust your intuition or go with the flow?
 
Digitizing/scanning will do the job. Also, you write you have the xyz start point, if you know the other xyz points, you can plug them into SW and have the model.

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP2.0 / PDMWorks 05
ctopher's home site
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Actually CMM (coordinate measuring machine) was what I was looking for (same thing, different name). I had heard of it before, but couldn't remember what it was called, therefore I couldn't google. I found it this morning and called and found several in my local area and am going to take my parts to one tomorrow.
 
There are many types of this scanning technology. I think the general sub-heading is "reverse engineering." Not sure what I think of the term, but anyways.

There are CMM's that are generally servo arms, you point the arm where you want a datum point and the servos record the 3D position of the tip. The FARO Arm is a pretty good example:

There are also non-contact methods like the one Heckler linked to. It really seems to depend upon your desired precision and the size of the part. I've heard of some of these CMM's being used for entire aircraft fuselages.

A laser scanning device will give you a point cloud, which can then be processed into surface data. An articulated arm gives you as many points as you care to click upon - although the software will generally recognize sommon shapes (2 points for a line, 3 points for a circle or plane, etc.) It sounds like your usage would entail a CMM to describe the 3D spline curve, then you could sweep your cross-section.

Sorry for the novel-length post, I just think this stuff is really neat.
 
What I *wish* I could find is a place where I take my parts, they lay them on a table, push a button, bam, scanned 360 degrees, maybe even a penetrating scan like an MRI, CAT scan or 3D Xray, for inside surfaces/cavities, then translated into a nice 3D cad file of my choice (SW of course).

I know that technology has to be out there, not sure what its called, but its few and far between and way out of my price range. Its a shame, its that way right now. When its mainstream, where Joe Common can afford it, it seems like that would create a boon of new parts/inventions because it would make the creation/reproduction of parts so easy.
 
Hmmmm, can it make me a cup of coffee too? Just kidding luke, I understand what you seek and the Faro arm is the closest thing that comes to my mind that is a common low cost solution in manufacturing.


In the scientific world it is not uncommon to use xray technology for that sort of thing but I am not sure how or where you can find someone to do that.

Try this:
Google: "stereo lithography"
also try :"rapid prototyping"

Fill what's empty. Empty what's full. And scratch where it itches.
 
Maybe check with the big auto corps. Don't they do something similar with from clay to CAD designs?

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP2.0 / PDMWorks 05
ctopher's home site
FAQ371-376
FAQ559-1100
FAQ559-1091
FAQ559-716
 
luke1201,

Yes, technology of this type exists--try the Hollywood arena, more than the CAD arena. They do scans of this type with lasers all the time. The problem then is getting it into a standard CAD format (as opposed to non-CAD Hollywood format).

A couple of my friends developed a great laser scanner back in college, but I don't think it was ever developed all the way to market. The data is often brought into Alias|Wavefront or 3D Studio Max, or some other free-form modeling program. Think Pixar, and that sort of thing. If you need precision (as Hollywood doesn't, necessarily), you might want to stick with some of the methods listed above. This is certainly under the "reverse engineering" category.

You could also model it yourself.


Jeff Mowry
Reality is no respecter of good intentions.
 
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