well i read that they only made it looks like he was standing on the ledge because if he was struggling there, then it would kill the drama. also, if he was standing on the ledge and they showed his legs in thater, it would also slightly ruin the mood. they used the excuse to beam the sun down to make a glare in the water to put up kind of a..."halo" effect around aeris, and that's also why they moved the shadow that cloud would normally give off. i call it like i hear it, what i just said wasn't MY actual idea, it was from the link i posted a few replies above.