3D Printed Model has blemish

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Reynard1066
Posts: 27
Joined: Sun May 10, 2020 7:27 am
Location: Scotland

Re: 3D Printed Model has blemish

Postby Reynard1066 » Mon Jul 06, 2020 10:53 am

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.
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TomB19
Posts: 161
Joined: Wed May 01, 2019 4:58 am

Re: 3D Printed Model has blemish

Postby TomB19 » Mon Jul 06, 2020 1:17 pm

abasel wrote:
Sun Jul 05, 2020 10:17 pm
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
Posts: 27
Joined: Sun May 10, 2020 7:27 am
Location: Scotland

Re: 3D Printed Model has blemish

Postby Reynard1066 » Mon Jul 06, 2020 1:30 pm

Select the Mesh Design workbench.
Edit->Preferences.
Import-Export, select Mesh Formats tab, Export group box.
drmacro
Posts: 1358
Joined: Sun Mar 02, 2014 4:35 pm

Re: 3D Printed Model has blemish

Postby drmacro » Mon Jul 06, 2020 1:34 pm

Reynard1066 wrote:
Mon Jul 06, 2020 10:53 am
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... 8-)

;)
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
Reynard1066
Posts: 27
Joined: Sun May 10, 2020 7:27 am
Location: Scotland

Re: 3D Printed Model has blemish

Postby Reynard1066 » Mon Jul 06, 2020 2:06 pm

The FC file is some 17Mb.

Attached is the STL file from Blender.
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Skittle.stl
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drmacro
Posts: 1358
Joined: Sun Mar 02, 2014 4:35 pm

Re: 3D Printed Model has blemish

Postby drmacro » Mon Jul 06, 2020 3:32 pm

Reynard1066 wrote:
Mon Jul 06, 2020 2:06 pm
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:
Attachments
Skittle-mac.png
Skittle-mac.png (146.99 KiB) Viewed 88 times
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
Reynard1066
Posts: 27
Joined: Sun May 10, 2020 7:27 am
Location: Scotland

Re: 3D Printed Model has blemish

Postby Reynard1066 » Mon Jul 06, 2020 4:36 pm

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
Posts: 1358
Joined: Sun Mar 02, 2014 4:35 pm

Re: 3D Printed Model has blemish

Postby drmacro » Mon Jul 06, 2020 4:58 pm

Reynard1066 wrote:
Mon Jul 06, 2020 4:36 pm
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.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
abasel
Posts: 105
Joined: Sun Sep 02, 2018 12:22 am

Re: 3D Printed Model has blemish

Postby abasel » Mon Jul 06, 2020 9:35 pm

TomB19 wrote:
Mon Jul 06, 2020 1:17 pm
abasel wrote:
Sun Jul 05, 2020 10:17 pm
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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