Heh, I too have been capable of shaping objects out of 3d.

Whenever I want to ''create'' an object out of thin air, I just turn into a totally ''emotion-less'' and passive state, then the object I want just comes out of thin-air (or from the ground). It's pretty hard to master for most, but it's cool when you can just go THINK "I want this" *Plop* "Giant Mecha appeared out of nowhere".
Yes you read it right, THINK, don't shout. that's how I do it.

Though if you can't master it, ''imagining stuff behind you or behind stuff'' isn't that bad now is it? You still achieve what you want, even though it's true a ''side-path''.