Hi,

I would like to make a nice rounded hole, but the surface doesn't seem proper. I checked it with a mirroring material. I tried to set the 'set normal angle' to 85 degree, and set the edges to soften edges, but neither help. What is my mistake?

If I apply a mesh smooth, it looks good, but, I think it should be nice without smoothing as well. I do not want make ugly models/wires, so please give me advices.

thank you very much

There is nothing wrong with your mesh. I think it is really obvious that a low res mesh cannot render like a perfect smooth surface, especially if you assign a phong or blinn with sharp glossiness like you do in your viewport. Interpolation of surface normals has its limits. Expressed somewhat exaggerated it is like wanting a cube look like a sphere...
That you can see those artifacts in your viewport doesnt mean that you see them in your final rendering, you should have a try with your final materials. If you still notice them  you could apply a smooth modifier to only those faces or if using mental ray as renderer apply a surface approximation to your critical meshes, then they only get smoothed at render time.

PS: the value of "Set normal angle" means the maximum angle value neighbouring face vertex normals may have to become interpolated. For example your edges should start beeing interpolatet at 35 degrees or so, if you now set 85 degrees the result just looks the same because this value is just a treshold value.

Thank you very much Nowayfra!