What setting is causing this effect? Weird top layer.

[ido]

I have 2 Prusa mk2s profiles, one that comes from Simplify3D and the other coming from a user from the Prusa forum.

I printed an object only to notice the pattern difference on the top layer. This difference is also seen in the preview screen within S3D. I tried to compare the 2 different profiles but cant find what is causing this. Perhaps a more experienced S3D user knows.

Same object, but sliced using different profiles



thanks in advance.

[brian442]

I'm guessing your part is not perfectly level. Because the top surfaces are at a slight angle, that's why you're seeing the layer changes across the surface.

[ido]

I am thinking that too, but looking at it, it looks ok, mmmm
more to investigate

[gearsawe]

This can happen from low accuracy on a STL file. you might have built a part with a shelf on it where it was designed at 1.2 but when you open the STL and start looking at data which make it up the z values for some levels might be 1.19999999999999923123 and other 1.2000000000000001233 for all the vertices on the same level. So when the slicer takes a stab it and slices it at 1.2 it see some parts are below which will not slice. Or simply it is not level or flat to the build platform. just guessing the 2 profiles have different layer heights?

just for fun double click a part and change the ZOffset to -0.01 and see if the oddity goes away.

[ido]

Both profiles have the same layer height. But indeed, if I change the Z offset, suddenly the model looks perfect when sliced.
Also default Z offset when I use "center and arrange" is -0.13, so the model isn't leveled to the service to begin with.