Hi, I would want to know if these are "visualization's errors" due to my graphics card...or are they due to a wrong sleep-construction of the surface? (excuse me for my scandalous English...)

It seems you are very tired... :))
"sleep construction" ???
Letter "W" isn't even close to "L" :))

Sorry, I found it funny...

The answer is : Go to options window and check the "Add detail to inflections"

Hi Paolino,

Neither first nor second... It is sufficient to turn a particular option on. Look here.
You can also show a control points and check that their structure look well - no distortion.

Petr

thanks JTB and tyglik, resolved problem!
...it is better perhaps that I go to sleep...

I suppose I should turn this on by default pretty soon. It slows things down a bit but not really too terribly.

oh cool that helps me too

i was getting sweep anomilies - or so i thought