# 3D Design / 3D Scanning / 3D Modeling > 3D Printing Slicer Discussion >  printed patterns of flat surfaces

## grue

hello.  new to 3d printing. i have a creality cr-10s.  i noticed when printing some flat surfaces like a rectangle or square, the printer prints concentric rows from the outside in, creating an overall pattern of 4 triangles, points in the center.

in a logo model i have, a box with raised letter in the middle top, the area around the letter is recessed, so it's like carved in, the pattern it printed for that lower flat area is not an even pattern, it prints a triangle in one direction then another triangle in another direction and smaller etc...  it looks like random sized triangles and random orientation of the triangles, setup to fit around the curved letter and the outside walls of the recessed area.

is there a way to adjust that in the actual 3d model, or in the slicer software?  or is that pretty much what you get.

in my 3d model, i have created a simple box, then inset the top surface, the extruded the inset face down a bit, the shape merged the letter, then selected the letter face and extruded it upwards the same amount the face was extruded down.  so the letter looks like it was carved in.  maybe my models needs to have that surface around the letter subdivided into even squares or triangles?

thanks!

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## fred_dot_u

Your slicer software has a setting for infill both internal and external. The external settings are apparently set to concentric and should be set to rectilinear. If you would provide the name of your slicer, it may be possible to have a more concise answer.

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## grue

> Your slicer software has a setting for infill both internal and external. The external settings are apparently set to concentric and should be set to rectilinear. If you would provide the name of your slicer, it may be possible to have a more concise answer.


thank you fred!  i was able to track down what looks like the setting you mentioned in cura 3.1.  tricky of them to hide it and post the settings user manual under version 2.0 on their website ha!

so now when i preview the box with the letter carved into it, if set to _concentric_ then that top surface looks all random triangle like.  switching to _lines_ it filles in the surface very nicely.

since my letter type face has a circle in it, like a dot over an _i_ that changes from concentric circles to lines as well.  it's definitely nice looking with lines, but it must be a or b not a mixture of both.

can't wait to print it again!

EDIT: actually, when i opened the logo box initially, the surface looked nice with concentric lines, like the bottom.  it was when i scaled the box +200% that the random triangles appeared.  like i said though, lines as the top/bottom pattern look good too.

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## grue

hm.  in cura 3.1 i'm not seeing this out of place lines on the bottom layer or the top, these prints are in progress, but the support failed so having to restart the print.  they seem to correspond to the print nozzle path according to the layers view in cura.  could it be some odd infill problem? thanks.

20180203_190954.jpg20180203_191000.jpg

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## grue

update. indeed someone else has had this issue  :Smile:   i saw that retraction seemed to be the issue.  in cura i was able to disable combing mode, i set it to off. then i made sure retraction was enabled.  i did nothing with z hop when retracted.  the 1st layer looks better with no angled line in it and i'd guess that the infill will not have those lines either.

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