By "set conditions" i assume you mean:-
1) Max available TO power or thrust,
2) Aircraft trimmed for TO,
3) Most unfavourable CG position,
4) max sea level TO weight,
5) Aircraft in most critical TO configiration with the gear up,
6) The aircraft airborne and ground effects negligble,
7) for props - the inoperative engine prop windmilling or feathered.
These criteria are used to determine Vmca.