Legality of animated ?

While recently researching software designed to create animation like “POSER” or “DAZ” I searched 3D models, what I found inter-mixed in the results were several sites dedicated to the creation of animated using the creation of life like renderings of people engaged in ual activity’s. At first I was amazed at the artistry of the graphic artist and the capability of the state art software., but soon found some very disturbing images created obviously to appeal to the fantasies of pedophiles. Child like renderings engaged in ual situations with adult renderings in a storybook fashion and occasionally mpeg type format. Anatomically the graphics were very realistic. While I realize that no living child is being exploited, I still wonder of the legality of portraying these types of situations in such a life like manner.