netfabb repair ruins smooth surface of model

I have run automatic netfabb repair (following the Shapeway tutorial precisely) on a .stl file, and I am now noticing a difference in the surface of the repaired .stl file from the original file, when I render it in Keyshot (see attached image to se the difference).

It doesnt look good, and I do not have confidence in uploading this file to Shapeways. What am I doing wrong? Is this normal? Can I adjust something in the repair process to avoid it from happening?

Hope someone will help!

Thanks

Same shader settings in both images ? To me it looks like the software varied the surface normals of the triangles in the render of the "original" stl to get a smoother appearance. (How big are the ripples compared to the entire object and the printer resolution - stl is a triangle mesh so there is bound to be some roughness if you look closely enough ?)

the model is made in zbrush where the surface is totally smooth, like in the original render.

The ruined surface is from the file where I have run the atomatic repair in netfabb and opened that .stl file in Keyshot.

Is it normal that the surface get like this after repair in netfabb??

The object is very small it is a ring.

This sometimes happens when you export, an exclamation mark appears informing you that the model has degenerative triangles or manifold edges to be repaired. If you choose to 'Optimize' then this may roughen your model. There is a tolerance setting to adjust that may help. For a better explanation look up the online help file. It may be best to try to fix these degenerate triangles and manifold edges in your original software before you try Netfabb.

Thank you! That helped a lot!