Oops, my reply came after yours Ray, making the whole thing a bit confusing :-) I don't want anything nearly as detailed as the Aha video. It's literally lines roughly drawn with a pen on paper like a quick outline drawing done in biro. The objects don't actually need to look 3D at all. In fact, I would prefer it if they didn't. But some of the objects will need to rotate, for example a crane which will swing round. It seems to me that if this is created as a 3D object it will be easier to achieve this effect than redrawing the object in a different position in each frame.
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moto