Strange surface with higher quality

[Smitti 0]

Hi all

Im pretty new to 3D prints and want to print a mobile phone case which i have downloaded from thingiverse.

If I print with standard quality, everything looks fine (Pic1)

 

If i set the quality to to dynamic or super quality, some strange things happen to the surface. (Pic2).

 

Do someone know what impacts this behaviour?

 

Thank you and best regards

Smitti

[GregValiant 1,357]

There may be something going on with the model.  If a defect is lower than 1 layer height then Cura may miss it.  Lowering the layer height could catch it and Cura wants to print it that way.

Use the "File | Save Project" command and post the 3mf file here.  It will contain the model, your settings, and your printer.

Sometimes a model can contain artifacts like that if the designer altered a model and wasn't careful when cleaning up from a previous design.

[Smitti 0]

Hi Greg

Thank you fro the reply. I have attached the 3mf. In Thinkercad the model looks fine.

 

BB Cover I14 Pro.3mf

[obewan 37]

Flip it over and print it face down, looks a lot better.

[obewan 37]

Had another look and it seems the model is not quite laying flat on the buildplate.

click on the model and open the rotate screen, in there is the option to lay flat.

But printing it that way up will probably need support.

Edited September 13, 2023 by obewan

[GregValiant 1,357]

This is one of the side holes.  You can see all the faceting, and that one long skinny triangle forms an extra surface.  That makes it a tough slice.

 

Here is the report from formware.co/OnLineSTLRepair

--> 0 Naked edges (?)
--> 0 Planar holes (?)
--> 0 Non-planar holes (?)
--> 133 Non-manifold edges (?)
--> 177 Inverted faces (?)
--> 8 Degenerate faces (?)
--> 15 Duplicate faces (?)
--> 0 Disjoint shells (?)
-> Repairing: 100.00%
----- Repair completed in 9039ms ------
-> Vertex count changed from 13298 to 13994 (+696)
-> Triangle count changed from 26886 to 28280 (+1394)

 

Even after repair that small error remains.  That tells me that it isn't affecting the integrity of the model, but it is affecting how it slices.

I think this is what @obewan is referring to.  Those areas on the left end are simply taller than the rest of the top.  This slice is at 0.1 layer height.

 

I used MS 3D Builder and subtracted .05mm off the top.  You can see that the defect is gone.  This is also  at 0.1 layer height.  You can see that this one is 125 layers and the one above is 126 layers.

 

One more.  This is the skin under the logo.  The logo was at a slight angle when it was subtracted so one side goes down before the rest of it.  Computers are dumb, but they are amazingly accurate so it wants to print the model it was given.

Somehow, someway, the model got out of square.

[Smitti 0]

3 hours ago, obewan said:

Had another look and it seems the model is not quite laying flat on the buildplate.

click on the model and open the rotate screen, in there is the option to lay flat.

But printing it that way up will probably need support.

Hi Obewan, thank you, that will fix the Problem. Flipping causes Support in the Logo which is a pain to remove 🙂

[Smitti 0]

54 minutes ago, GregValiant said:

This is one of the side holes.  You can see all the faceting, and that one long skinny triangle forms an extra surface.  That makes it a tough slice.

 

Here is the report from formware.co/OnLineSTLRepair

--> 0 Naked edges (?)
--> 0 Planar holes (?)
--> 0 Non-planar holes (?)
--> 133 Non-manifold edges (?)
--> 177 Inverted faces (?)
--> 8 Degenerate faces (?)
--> 15 Duplicate faces (?)
--> 0 Disjoint shells (?)
-> Repairing: 100.00%
----- Repair completed in 9039ms ------
-> Vertex count changed from 13298 to 13994 (+696)
-> Triangle count changed from 26886 to 28280 (+1394)

 

Even after repair that small error remains.  That tells me that it isn't affecting the integrity of the model, but it is affecting how it slices.

I think this is what @obewan is referring to.  Those areas on the left end are simply taller than the rest of the top.  This slice is at 0.1 layer height.

 

I used MS 3D Builder and subtracted .05mm off the top.  You can see that the defect is gone.  This is also  at 0.1 layer height.  You can see that this one is 125 layers and the one above is 126 layers.

 

One more.  This is the skin under the logo.  The logo was at a slight angle when it was subtracted so one side goes down before the rest of it.  Computers are dumb, but they are amazingly accurate so it wants to print the model it was given.

Somehow, someway, the model got out of square.

Hi Greg

Thank you much for your detailed explanation. I have downloaded another stl. from thingiverse and it looks much better.
But.. how can I remove this little angle in the Logo? I am using tinkercad. Or do you recommend another 3 D tool which is so easy to use?

 

 

[GregValiant 1,357]

"Or do you recommend another 3 D tool which is so easy to use?"  

I don't think any of them are "easy to use".

I like MS 3D Builder but it's a Windows program so if you are on MAC or Linux it isn't an option.  I've tried other software and there are problems with the leaving openings (non-watertight) or jagged edges.  3D Builder is not very intuitive, but it gets the job done for me and leaves a nice clean result.

It also has "Subtract", "Merge" and "Intersect" tools so you can customize an existing STL.  It does not have tools for adding chamfers or radii on edges.  For that you must go back to a real CAD app.  You can do it in builder but it is certainly no fun.

Blender has it's fans.  Mesh Mixer is also an option.

[GregValiant 1,357]

I tried to fix that model.  There is still some wonkiness in the bottom of the logo, but the top and bottom surfaces are now planar parallel so it's better.

I'd print it as Obewan suggested, but here it is the way you liked it.  This is a good model for Normal supports.

When you open  the 3mf you can just bring in the model.  If you open it as a project then your printer may be over-written.

 

GV BB Cover I14 Pro.3mf

Edited September 14, 2023 by GregValiant