RE: Difference between IMAC and Pattern
Pattern is only about precision aerobatics. There is a defined aerobatic box and geometric centering of center zone manuevers is one of the judging criteria. You must maneuver the model precisely within the aerobatic box to score well and do not need to be concerned with impression scoring to compensate for the lack of a defined box. Also, the sequences are longer, with roughly twice as many figures per sequence as with IMAC. Unknowns exist only in certain FAI contest venues, typically in the finals for the Nationals or potentially some other large or high stakes event. The K-factor targets for the sequences are achieved through figure selections that do not require a large number of snap rolls to raise the number, i.e. there is a higher emphasis on geometric complexity than adding snap rolls to figures.