Re: stl file comparison

From: Innomation Systems & Technologies Pte. Ltd., (
Date: Mon Jun 15 1998 - 13:18:17 EEST

Hi Mr.Greg,

Surfacer software from imageware can do the comparision,
but with point clouds. You can get the scanned data of the
rp component from any 3-D digitizer. You can use any standard
reference like parting plane or features to compare with the
original cad model. Here the comparision can be with
points to surface or point to point or surface to surface.

Converting the scanned point clouds to stl file directly is
not advisable (personal opinion) as any single outlier point can
drag your stl file out of limits. Also, there is better control available
in the software like "max. checking distance" to avoid these outliers
if you use point data.

Alternatively, we can unpolygonise the original cad stl file to
get points and this can be used to compare
with the scanned point data. The output will be a color map showing
the deviations.

Application Engineer
> From: Greg Morwood <>
> To:
> Subject: stl file comparison
> Date: Saturday, June 13, 1998 7:54 AM
> gudday again,
> Thanks for the responses on the mesh to stl question. I bit the bullet
> wrote a little piece of code to translate I-DEAS .unv files into .stl
> It requires a bit of hand fiddling, including fixing the normals
> but it seems to work. --available if anyone wants it.
> I have another problem though.
> Is there software available that will compare two stl files of the same
> (nominally) part. What I am looking for is some kind of report on the
> geometric difference between the two stl files. For instance, I might
> to compare an stl file from a scan of the SLA model with the .stl file it
> was made from. Is anyone doing this?
> Regards,
> Greg.
> For more information about the rp-ml, see

For more information about the rp-ml, see

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