Question: [![enter image description here](https://i.stack.imgur.com/vXXGd.png)](https://i.stack.imgur.com/vXXGd.png)

How can I smooth all crown but don't smooth the top of the crown? I did a subdivision surface, but this didn't work. All crown became smooth and changed form.

Answer: 
Here is a way to make a crown, maybe there's a simpler?

* Build a basic cube, delete its two side faces, give it a *Mirror* modifier.
* Drag up its central edge, add 3 vertical edge loops.
* Add some additional edge loops close to the angles so that it will sharp them later.
* Give your object an *Array* modifier. Choose a *Count* of 4. Enable the *Merge* option.
* Give your object a *Simple Deform* modifier / *Bend* mode. Choose an *Angle* value of 360°. If it doesn't turn around the Z axis, apply the rotation of your object.
* At last, give your object a *Subsurf* modifier (and press the *Smooth Shading* button on the *Tools* panel).
* Move a bit your edges with `G``G` to sharp the crest and the low of the crown.
* Apply the modifiers (except the *Subsurf* if possible), remove the doubles (where the 360° joint happens).

[![enter image description here](https://i.stack.imgur.com/ElpNJ.jpg)](https://i.stack.imgur.com/ElpNJ.jpg)
Add in more loop cuts on the subsurf mod. That should do it. I take it that smooth shading doesn't work?