Smoothing the Region?

There is a 2D Pi

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I successed transformed it to 3D.

extrudeImage[image_] :=    Block[{res, img},    img = DeleteSmallComponents[Binarize[image, 0.9], 500];   res = ImageMesh[img];   RegionProduct[res, Line[{{0.}, {10.}}]]]  img = DeleteBorderComponents@         ImageResize[Import[""], 100]; r = Region[extrudeImage@img, Axes -> True,          AxesLabel -> {"X", "Y", "Z"}]; r = TransformedRegion[r, TranslationTransform[-RegionCentroid@r]] 

enter image description here

I tried to rotate it to create a more 3D Pi, but the surface seemed to be too rough, MMA can’t export STL format.

RegionUnion@  Table[TransformedRegion[r, RotationTransform[i, {0, 1, 0}]], {i, 0,   Pi/3, Pi/10}] Export["test.stl", %] 

enter image description here

How to make the surface smooth so that 3D printing can be used?