I need a low cost instrument for 3d measurement.
I need to acquire a small surface (30 x 40 cm) for creating a 3d model and
the model doesn't have to be too accurate.
1: What kind of istruments do you know for 3d measurement (laser)?
2: Who are the best productors according to you?
3: Which of this instruments are near to my needs?
Thank. Paolo Salvucci
"Irshaad" ha scritto nel messaggio
not strictly. I'm interesten inall kinds of coordinate measurement not only
As far as i know there are other systems for 3d measurement which are not
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.
"Smelly Belly" ha scritto nel messaggio
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.
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.
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
3D space on a button press. The data can be directed into AutoCAD with a TSR.
Rhino receives it directly.
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'.