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Spencer Renosis
Hi,

I am having some trouble importing .stl files. The following I posted to the Makerbot forum, and I was directed to the Openscad mailing list:

<begin first post>

I am trying to import my chatterbox teeth ( http://www.thingiverse.com/thing:8138 ), which were originally created in sketchup, as well as all the additional hardware for it. Well, I have redesigned everything in Openscad, except the teeth themselves, which would be too hard to do in openscad.

So I want to import the .stl file. Now, I have been sitting here putting the finishing touches on the new mounting brackets for the teeth and I go to compile and press F6, and I get the following error message:

ERROR: Illegal polygonal object - make sure all polygons are defined with the same winding order. Skipping affected object.

Now, for some reason Openscad has no problem opening the files during editing and viewing with F5. But when I go to compile, it dumps out the above error message and the teeth don't get displayed. I have tried running the file through netfabb. I have also tried my luck with meshlab, but I am finding it to be very confusing.

I even tried exporting the teeth from sketchup as a different file type and importing into meshlab, and then I exported it as an .stl file from meshlab and it still gives me the error message. I did this maybe thinking that the .stl exporter plugin I use in sketchup has some kind of bug.

Does anyone have ANY suggestion on how I can fix this?

<end post>


And then I tried these things:

<begin post>

I tried cadspan, the model has too many triangles for cadspan demo, they need my money to process that many triangles.

I've been trying for many many hours to get this to work. I have tried netfabb cloudservices and basic studio. I tries Meshlab. I tried a suggestion to load it in meshmixer and then export it. I tried loading it in various programs, saving in just about every 3d file format possible, using just all the various programs to open the new format, and then generate an .stl in other programs.

I also tried saving as a .off format, which the openscad site claims openscad has the ability to import. But when I try import_off ("teeth.off"); it returns an error saying that .off importing is not yet implemented.

I thought I was on to something, when netfabb studio said there were 2 shells. I had right clicked the teeth, and then clicked select shell, and then created a new file from just the one shell. Apparently the second shell was a renegade triangle hidden in the model. I was convinced that this would fix it. No such luck!

Any suggestions?

This is really disappointing!


<end post>


Does anyone have any suggestions for why my .stl file would have an issue during compile? It works fine with F5 view. And no other program that opens stls has any issue opening the file!


Thanks,


Renosis

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Re: (no subject)

clothbot
Also post which version of OpenSCAD you're running and on which platform.

Andrew.

On 2011-05-06, at 9:52 AM, Spencer Renosis wrote:

Hi,

I am having some trouble importing .stl files. The following I posted to the Makerbot forum, and I was directed to the Openscad mailing list:

<begin first post>

I am trying to import my chatterbox teeth ( http://www.thingiverse.com/thing:8138 ), which were originally created in sketchup, as well as all the additional hardware for it. Well, I have redesigned everything in Openscad, except the teeth themselves, which would be too hard to do in openscad.

So I want to import the .stl file. Now, I have been sitting here putting the finishing touches on the new mounting brackets for the teeth and I go to compile and press F6, and I get the following error message:

ERROR: Illegal polygonal object - make sure all polygons are defined with the same winding order. Skipping affected object.

Now, for some reason Openscad has no problem opening the files during editing and viewing with F5. But when I go to compile, it dumps out the above error message and the teeth don't get displayed. I have tried running the file through netfabb. I have also tried my luck with meshlab, but I am finding it to be very confusing.

I even tried exporting the teeth from sketchup as a different file type and importing into meshlab, and then I exported it as an .stl file from meshlab and it still gives me the error message. I did this maybe thinking that the .stl exporter plugin I use in sketchup has some kind of bug.

Does anyone have ANY suggestion on how I can fix this?

<end post>


And then I tried these things:

<begin post>


I tried cadspan, the model has too many triangles for cadspan demo, they need my money to process that many triangles.

I've been trying for many many hours to get this to work. I have tried netfabb cloudservices and basic studio. I tries Meshlab. I tried a suggestion to load it in meshmixer and then export it. I tried loading it in various programs, saving in just about every 3d file format possible, using just all the various programs to open the new format, and then generate an .stl in other programs.

I also tried saving as a .off format, which the openscad site claims openscad has the ability to import. But when I try import_off ("teeth.off"); it returns an error saying that .off importing is not yet implemented.

I thought I was on to something, when netfabb studio said there were 2 shells. I had right clicked the teeth, and then clicked select shell, and then created a new file from just the one shell. Apparently the second shell was a renegade triangle hidden in the model. I was convinced that this would fix it. No such luck!

Any suggestions?

This is really disappointing!


<end post>


Does anyone have any suggestions for why my .stl file would have an issue during compile? It works fine with F5 view. And no other program that opens stls has any issue opening the file!


Thanks,


Renosis


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Re: (no subject)

Giles Bathgate-2
On 6 May 2011 15:13, Andrew Plumb <[hidden email]> wrote:
> ERROR: Illegal polygonal object - make sure all polygons are defined with
> the same winding order. Skipping affected object.

This is a known issue in OpenSCAD importing some STL's

Some thoughts on how to fix the code for this issue:

1) STL file contains "normals" for each facet, using the normal you
should be able to work out the correct winding for the facet.

2) Could the function void DxfData::fixup_path_direction()  in
dxfdata.cc be used to solve all these winding order problems?

Regards

Giles Bathgate

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Re: (no subject)

nophead


On 7 May 2011 11:01, Giles Bathgate <[hidden email]> wrote:
On 6 May 2011 15:13, Andrew Plumb <[hidden email]> wrote:
> ERROR: Illegal polygonal object - make sure all polygons are defined with
> the same winding order. Skipping affected object.

This is a known issue in OpenSCAD importing some STL's

Some thoughts on how to fix the code for this issue:

1) STL file contains "normals" for each facet, using the normal you
should be able to work out the correct winding for the facet.

I think the normals are often wrong in STL files as well, so they are better ignored.
 

2) Could the function void DxfData::fixup_path_direction()  in
dxfdata.cc be used to solve all these winding order problems?

Regards

Giles Bathgate
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[hidden email]
http://rocklinux.net/mailman/listinfo/openscad

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Re: (no subject)

Giles Bathgate-2
On 7 May 2011 11:22, nop head <[hidden email]> wrote:
> I think the normals are often wrong in STL files as well, so they are better
> ignored.

Yeah, as I understand, STL files are rather odd in the fact that they
encode the way a facet is facing using normals, but its redundant
since the way its facing can be determined from the winding order of
the facet.

Admittedly whatever application is exporting the STL is free to abuse
the standard in which ever way imaginable. So what I meant by 1) was I
think it would be quite simple to do a check to see if the normals
agree with the winding order, and if they don't we can attempt to fix
them using 2).

Regards

Giles