how to caculate area,force and moment in Fluent

mimibenben

here is my question: i get the Fluent caculated pressure data of a missle,now i use these data to caculate some part of the missile's(the tail is dropped) normal coefficience,in a simple integral way,but the integral results was different from the Fluent results. i want to know exactly how to caculate force and moment in Fluent,whether some faces are not included in some caculation of force or moment, so i can check if something was wrong with my integral program. by the way,some of my areas are different compared with the Fluent Report,and i don't know why. please give me help!thanks a lot!