未打大 tesellation!
1. select your model
2. open attribute editor
3. in the shape node, expand "Tessellation"
4. u can check the "Display Render Tessellation" to preview the smoothness of model (remember to check off when u finish)

5. expand "Advanced Tessellation"

6. check "Enable Avanced Tessellation"

7. u can tune the attributes "Number U", "Number V"
remember!! don't set the tessellation too high, it will make ur render very slow
