low cost 3d measuerement

you're talking about a CMM, coordinate measuring machine, right?

-- Hasta Luego

Irshaad (Faster than Bruce Lee)

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use a ruler?

hire someone to reverse engineer or measure your object on their cmm?

you want 3D measurement but give only 2 axis! what is too accurate? how many data points?

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not strictly. I'm interesten inall kinds of coordinate measurement not only "mechanical".

As far as i know there are other systems for 3d measurement which are not contact-based.

In my university, for example, I 've seen an optic system. The system is composed of a projector, a camera and a workstation. The system project a light with a "many parallel strips" pattern on the object you have to measure, takes a photo and process the image. Analyzing the deformation of the pattern the system build a virtual 3d model.

Of course there are many difficoulties: the object must not have too meny concavity, the color of the object should be omogeneus, the object shuld be glossy and not reflective, you can aquire only one side of the object per scan ..... however it can be a good choise for measuring large 3d artworks (statues ..) which cannot be measured by standard cmm or laser scanners.

Bye Paolo.

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The system has to be automatic and the measure should be instantaneus or at least very fast.

Not possible ( see below). Morover traditional cmm

resolution 0,5 - 1 mm

I intend to build a 3d system for prototyping and previewing shoes soles. As far as I know the process is still manual and i'm studing the possibility of building an automatized cheap system for doing it. For doing it i need to acquire somehow the bottom of the vamp (the upper part of the shoes made of lather) whic is mounted on a foot shaped support.

I even thougt to build an instrument on my own, based strictly on my needs, but before doing it I want to give a look at all commecialized gauges.

Bye. Paolo Salvuci.

If money is no object try x-ray ct scan

else stick with a manual gauge or create a custom fixtue to do repetative gauging for you.

you will need to answer the question "how many points" do you need.

Low cost, 3D measurement even if "not too accurate" is a difficult order.

A rotating base with a protractor. A fixed height gage column, with a horizontal 12 inch clock calliper is the cheapest method that comes to mind. About $60

Brian W

We have a Microscribe articulated arm 'sorta-CMM'. We got the 'high precision' and 'long reach' model, claimed accurate to +/-.009", and large enough to touch all of a basketball or about half of a car tire. The whole setup cost about $10,000, including a nice refurbished laptop, Rhino software, and two days of training for Rhino.

We get a lot of use from the laptop, and Rhino. The Microscribe pretty much gathers dust between dog- and- pony shows.

The Microscribe sends a series of characters describing the point location in

With a little practice, you can build a decent _looking_ image of most anything you can touch, but it's not accurate enough to use for inspection or for capturing the actual geometry of an object.

Yeah, Rhino can fit a surface to a point cloud, build circles or planes in space from three touches, stuff like that, but the generated model always comes out a little rough, with bumpy surfaces and edges that don't meet, stuff like that. Not Rhino's fault; the arm's data has a lot of scatter. Basically, you can build a sort-of 3D of an object, but then you need to go in and manually build a coherent and cohesive model over it, or spend a lot of time fiddling with individual points.

I think the original plan was to wear it out with use to justify the need for a bigger, more accurate Faro Arm, but we can't get anyone to use it twice.

I.e., 'not too accurate' is 'not too useful'.

-Mike-