i need to use some codes wrote by someothers,after i add some of it,the net 2005 told me something unhappy. as the .net 2005 said: MotionClip.obj : error LNK2019: unresolved external symbol "class Vector3 __cdecl operator*(class Matrix3x3 const &,class Vector3 const &)" (??D@YA?AVVector3@@ABVMatrix3x3@@ABV0@@Z) referenced in function "protected: void __thiscall MotionClip::init(class BVH *)" (?init@MotionClip@@IAEXPAVBVH@@@Z) so,what's going on? miss *.cpp or *.h file? Actually, i did it.