Wrong option Laure : NOT Shading rate but below that.
Smooth Polygons to ON on every group you want them on.
And Crease Angle at 180 on every group you want smoothed.

"Smoothing" is one of Posers most flexible tools.
Beats Subdeviding from sunrise till sunrise in flexibility as you can set it for each and every group seperadly. => Smoothing on demand, at group level.

Or As I said before, just set it once in General Preferences.
Do not forget to set Smoothing to ON in the render settings.

 

;-)

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!