3D Printed Model has blemish

[Reynard1066]

I create a B-Spline model in Blender and exported as an STL. Excellent mesh and consistent triangle size at a given height.

Imported into FC and created a solid from the mesh, then a base feature. I tried to pocket the base but FC wasn't having it. More FC mysteries I have yet to learn.

[TomB19]

I also changed Maximum Mesh Deviation to 1umm and the blemish was reduce to an unnoticeable size. Large file but good result

May I ask where this is configured? I can't find it in pre-0.19.

[Reynard1066]

Select the Mesh Design workbench.
Edit->Preferences.
Import-Export, select Mesh Formats tab, Export group box.

[drmacro]

I create a B-Spline model in Blender and exported as an STL. Excellent mesh and consistent triangle size at a given height.

Imported into FC and created a solid from the mesh, then a base feature. I tried to pocket the base but FC wasn't having it. More FC mysteries I have yet to learn.

Without the stl and maybe the FreeCAD file for others to look at...it will probably remain a mystery...

[Reynard1066]

The FC file is some 17Mb.

Attached is the STL file from Blender.

[drmacro]

The FC file is some 17Mb.

Attached is the STL file from Blender.

Import into Blender and it says there are 128 non-manifold edges and 128 non-manifold verts.
And all the polygon normals are reversed. (pointing inward)

This wold be expected to fail, but:
In FreeCAD I had to set the tolerance lower than .1 to convert mesh to shape.
Afterwards there are a large number of self intersecting faces & edges according to Check Geometry.

After correction in Blender it seems fine:

[Reynard1066]

Hi drmarco,

Thank you for looking at this. You are correct the normals are all pointing inwards. I have done a recalculate to outside and will try again.
I am a bit concerned that there may be a very small hole in the top centre that didn't close during the 360 spin. To be checked out.

Again thank you for the pointer. Still a bit of a noob with FC.

Reynard

[drmacro]

Hi drmarco,

Thank you for looking at this. You are correct the normals are all pointing inwards. I have done a recalculate to outside and will try again.
I am a bit concerned that there may be a very small hole in the top centre that didn't close during the 360 spin. To be checked out.

Again thank you for the pointer. Still a bit of a noob with FC.

Reynard

There was one in the top and the bottom, that is the source of the non-manifold.

[abasel]

I also changed Maximum Mesh Deviation to 1umm and the blemish was reduce to an unnoticeable size. Large file but good result

May I ask where this is configured? I can't find it in pre-0.19.

For export there is a setting from Mesh Design WB

Edit > Preferences > Import-Export > Mesh Formats tab > "Maximum mesh deviation"

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OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/NewZealand (en_NZ)