Boolean modifier distort primitive

I embossed some text in a cylinder using the Boolean difference modifier. It works fine, but when I use the smoothing tool on the cylinder I get the distortion shown in the attached photo. It should just show OKO on a smooth surface. This also happens with even simple modifiers like a cube.

Is there a way to do this and still have a smooth surface?

thanks

What smooth tool ?
Did you convert text to a mesh ?
Did you apply the modifiers
Have you cleaned up the mesh so you have just quads/tris and no faces with > 4 sides

What does the mesh look like ? I assume you have lots of very long thing triangles. These will generally look bad with smooth shading on non planar surfaces.

Why have you failed to supply a download link to a demo .blend file for review ?

Also please use the appropriate support forum for support questions rather than just posting in the first subforum you see ! Threads moved.

Boolean modifier really messes up the mesh sometimes, try these settings and see if that helps