maker2
Posts: 113
Joined: Sun Jul 19, 2015 9:05 am

additional "features" mysteriously appeared on part?

Tue Aug 06, 2019 3:22 am

My print is underway and have noticed that there are additional traces present on the top layer that are apparent in the slicer (didn't notice them), but are neither present in the part nor visible in the mesh.

Any ideas what might be going on?

(Attached photo from slicer, screenshot of mesh and factory file itself.

The two disc like regions should be perfectly flat but they have additional tracks cutting accross them creating rectangular regions. As indicated by purple arrows. )
mesh.png
Attachments
factory.factory
(289.75 KiB) Downloaded 11 times
extra traces.png

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dkightley
Posts: 2088
Joined: Tue Mar 10, 2015 4:09 pm

Re: additional "features" mysteriously appeared on part?

Tue Aug 06, 2019 4:56 am

The surface of those indents must be at the cusp of the threshold between one layer and another...and you're getting an extra layer for some parts of the face.

Adjust the layer thickness to 0.2001mm and the effect goes away!
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

maker2
Posts: 113
Joined: Sun Jul 19, 2015 9:05 am

Re: additional "features" mysteriously appeared on part?

Tue Aug 06, 2019 5:08 am

That's a good fix.

Thanks.

Too bad didn't spot it before printing.

maker2
Posts: 113
Joined: Sun Jul 19, 2015 9:05 am

Re: additional "features" mysteriously appeared on part?

Thu Aug 15, 2019 12:47 am

In case it helps someone debugging, here's a similar example which is different because the activity appears in EMPTY SPACE.
Attachments
case_LEFT.factory
(310.05 KiB) Downloaded 10 times
image.png

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dkightley
Posts: 2088
Joined: Tue Mar 10, 2015 4:09 pm

Re: additional "features" mysteriously appeared on part?

Thu Aug 15, 2019 5:19 am

You're incorrect in saying your issue is similar.....

Having REPAIRED the shape (using the Win10 app 3DBuilder), the reported artefacts are no longer created.

Updated factory file attached.

I trust you realise that one of the bi-products of a slicer that slices so much faster than other slicers is that the mesh of the shape has to be far more accurate and contain fewer errors and artefacts!
Attachments
case_LEFT.factory
(343.38 KiB) Downloaded 9 times
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

maker2
Posts: 113
Joined: Sun Jul 19, 2015 9:05 am

Re: additional "features" mysteriously appeared on part?

Thu Aug 15, 2019 5:32 am

Interesting. Thanks.

Were there any clues that the model needed "repair"? (Would have sworn that it was fine because have printed more or less the same thing many times. Have never repaired a model before.)

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dkightley
Posts: 2088
Joined: Tue Mar 10, 2015 4:09 pm

Re: additional "features" mysteriously appeared on part?

Thu Aug 15, 2019 6:22 am

No "clues" other than the fact that there are artefacts generated.

There has been issues like this reported on the forum for a number of years now where other slicers seem not to be affected by such errors in the mesh, and S3D sees the errors as real lines and surfaces. All long-term S3D users are aware of these shape issues....and in fact its been said that around 25% of the downloadable stl files have one or more error of this type.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

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