But what about the people who can't afford a 3d modeller that supports these formats? This is why i'm asking for a convertor for UU.
UU does Collada. As long as the built-in format can be represented in XML (although not necessarily exclusively so), "converting" it is at worst, a trivial task that can be automated.Also Collada was designed with video games (specifically video games for the PS3) in mind and is an open format.