Blender STL errors - Shapeways doesn't like my STL

[Penrhos1920]

So I'm new to Blender having had to stop using autocad as I no longer have a license through work.  I've uploaded my first STL to Shapeways and this is what 3D Builder thinks the STL is:

 

 

and this is what Shapeways makes of the STL:

 

 

Notice the missing planks on the doors.  What's going on?  How do I get the planks to appear?  This is after using 3D Builder to repair the mesh as it was incorrectly defined by Blender !!

[MikeTrice]

Chances are you have some errors in the Blender model.

 

Make sure that the model is manifold and then check the "normals" are correctly orientation.

 

I use an early version of Blender so the following may not be correct.

 

Open the stl in blender by importing it.

Select the van then go into edit mode.

Choose vertices mode and ensure no vertices are currently selected.

From the "Select" menu choose "Select all by Trait" and "Non-Manifold"

 

If any vertices are highlighted you have problems with the model.

 

For the Normals switch the view to "Faces" then select all faces ("A") then select "Mesh", "Normals" and "Recalculate Outside"

 

Worth doing the non manifold test again just to check all is well.

 

[JCL]

If you're on Windows 10 or 11, another option is to open 3d Builder (you may have to download it from the MS Store).

1. Open the STL in 3D Builder, click on the tick mark above "Import Model" in the toolbar,
2. Click on the 'repair' panel, bottom right.
3. Click on the "hamburger menu" in the top left (three horizontal lines)
4. Choose Save As and choose the STL format. I tend to add an f to the end of the file name so that I know it's kosher.

This is a part of my workflow now.

 

cheers

 

Jason

[Penrhos1920]

Thanks folks.  STL now fixed.  3Dbuilder first followed by importing back into blender to find the residual errors.  If I skip the 3dbuilder step blender shows that its own STL file has 100s of errors!

 

In this case the error was several inside faces.  I find it hard to understand why blender creates a file with so many errors.  I’ve looked at STLs made with autocad and they are faultless.  Years ago autocad used to require you to union all the parts you were exporting before creating the STL but now it usually does it all by itself.  I guess that’s the difference between software created by a company  or open-source.

[PaulaDoesTrains]

If you truly believe the problem is caused by bugs in Blender then I'm sure the Blender devs would be happy to look at it.