Dear list,
A few weeks ago I reacted on a mail of Ed Grenda, on the small
CNC mill and scanner from Roland Corp. I gave my view on the mill
and promised to soon post my experiences with the scanner.
Here they are.
Best Regards,
Lex Lennings.
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Some experiences using the PICZA lowcost 3D scanner.
The Picza comes in as a cute little desktop machine:
dimensions a bit above 30 cm square, nicely styled outside.
It must be used with a separate AC adaptor, and Win 95
control software (both included with the machine).
Connection to the PC by serial cable (either Com1 or Com2
can be selected).
The object to be scanned must be attached to the table,
for which aim a piece of clay is present. Max scan volume
is 150 x 100 x 40 mm. For the actual scanning a needle is
used that comes down and touches the object. In all cases
a rectangular grid of points is measured, of which the
resolution (pitch) for both X and Y can be set (any value
between 0.05 and 5 mm). The scanning is done using some
intelligence: for each line first locating the object on
several heights (layers), then measuring.
Control of the machine is quite simple using the Picza
software: set the area to be scanned, set the two
resolutions and press scan. The scanned points are
automatically converted to triangles (large triangles
are generated on flat areas). After the scanning a number
of options is available like viewing, rendering,
deskewing, smoothing, inverting etc. Saving is done in
a proprietary format, export is possible to DXF (entity
3DFACE) and VRML V1.
Our first observation is positive:
The system works ! We could directly produce prototypes
using our DeskProto RP system.
However, a number of side remarks has to be made as well.
- As the needle has a sharp point and is thus tapered,
vertical walls cannot be accurately measured.
- The repeatability is not perfect: as said the Picza measures in
layers and in the result we could vaguely see some transitions
between these layers. We were told by an experienced user that
it helps much to fixture the piece as high as possible: when the
needle can stay high up the result is more accurate.
- The Picza software is not great. It looks like a childrens game
(which is not really a problem), it is dreadfully slow in drawing
etc, and it is very memory-intensive (continuously swapping memory).
Regularly warnings are issued that the program is short of memory,
however after ignoring it just continues.
- No STL output: our free DeskProto demo can convert DXF to STL,
however no guarantee on correct facet normals.
In our test we actually measured a small Mickey Mouse
(dimensions ca 40 x 40 x 20 mm) at 0.2 mm resolution.
Total scanning time ca 6 hours (the Picza software gives an
estmation of the time to go). The software reported insufficient
memory (32 MB machine), however the resulting DXF (ca 11 Mb) was
fine. It did indeed include all small details from the original.
A direct software interface to the Picza is available for
the ArtCAM 3D CNC engraving software. This is called ArtPIX, and
directly reads the proprietary Picza PIX format.
My overall conclusion is positive: for a very low price you have
in house 3D scanning (the price of the machine is below 2,000 USD).
The accuracy ans size limited, however the price-performance ratio is
great. We have thus decided to include this machine in the range
of products that we do offer. I hope we can soon show some
pictures on ouw Web Site.
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Delft Spline Systems, The Netherlands.
We offer DeskProto: affordable Rapid Prototyping using CNC milling
mailto:info@spline.nl
website:http://www.deskproto.com
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:47:13 EEST