One possible cause for a "freeze" delay if you have a few fairly complex models is the trace that is routinely sent out by the mouse pointer. You can test if this is the cause by placing a few of you models around you, then when you rotate them into view see if the position of the mouse arrow makes a difference as to when exactly the freeze occurs.

The way to eliminate this problem is to make sure the UNTOUCHABLE flag is turned on for each model.

my.UNTOUCHABLE = ON; // C-Script
my.flags2 |= UNTOUCHABLE; // Lite-C

Drawback is that the model is not detected by the mouse any longer in case you need it to be.

cheers