[Strange patterns over several layers of print]

Hi 

Does anyone know which setting(s) or conditions can cause or prevent these weird patterns? I find it often but not always and as shown here, on the same part, angle and plane, some areas can have it while others don't.

BTW, the yellow is PLA and the red is PET. Printed months apart, before and after nozzle maintenance and replacements also. I think it only occurs on flat surfaces - can't recall ever seeing it on a curved surface now that I think about it.

 

[Hollow print intent not honoured]

Hi @GregValiant, I now found the the problem, I missed one default setting to change for this case: The number of bottom layers!

 

[Hollow print intent not honoured]

Hi @GregValiant, thanks for your reply but no, the facets are intended and not the problem that I am describing.

In the image, both the faceted and spherical balls show the same problem: there are additional layers on the insides of the balls, but only at the bottom. With the chosen sizes and settings, both balls are suppose to have wall thicknesses of only 2 layers, but for some reason both show additional layers. In the new attached image, I  hope this detail is a bit clearer. I also attached the project file. The spherical file is very large because of its high resolution so I did not attach it, but it's just a solid sphere. 

WDI3M_balls.3mf

[Hollow print intent not honoured]

I wanted to print a hollow ball (from a solid STL model of a sphere) by using 0% infill and no supports, but in the preview I see a very strange few layers on the bottom inside that I can't explain and won't be able to remove afterwards.

See image attached.

Any idea what this can be?

 

I installed the new version 4.7.0

Faceted ball.stl