I wa watching the films and was wondering how the transformers just spawn more and more. For example soundwave made the panther thing then it made the thin robot and all those construction guys too, then they made the huge robot with the balls.
Haha, well from what I remember, the bodies were assembled on cybertron. But that wasnt it. In order to create actual life the transformer needed The Matrix, an orb (or in the live action movies, a slender metal thingy?) which would allow a spark from the Allspark (which is essentially transformer heaven if I remember correctly) to enter the body and give it life. This can also reanimate deceased Transformers. The only other times I remember transformers coming to life in the show, is when the autobots found the Dinobots and somehow brought them back to life? Then there was the world eater, Unicron, who was able to upgrade other transformers. An example would be the transformation of Megatron into Galvatron made possible by Unicron.
It's all science fiction.