Have you not seen stereoscopic 3D? Everything looks like it's a billboard. It is basically taking a bunch of pieces of an image (which are all 2D) and then giving them "depth" but essentially it's still 2D images on different "planes" so to speak. I don't think it'll really matter at all.
It's two 2D views of the same 3D scene from different positions. Which is exactly how eyes work in real life...
I'm wondering about calibration, as to get the perfect effect you need to specify an eye separation (distance between the two cameras) and focal range (distance at which the two camera views cross), and the ideal can be different for different people. In NASCAR Racing 2003 in 3D it took a few minutes to dial in the perfect settings, but once I had the results were amazing.
I think the closer you are to something the more true 3D the effect will be, for instance the planet in stardust is supposed to look great. The further in the distance something is the less information you get from looking at it from each angle and so your eyes rely more and more on visual cues like how an object is lit instead. If things in S3D are not lit properly the futher away they are the more they will look like cardboard cutouts rather than solid 3d objects. The good news is that current 3d games use lighting, shadows etc as there only tools to create a 3D effect and thus have got quite good at it, so it shouldnt be an issue. If an object looks 3D in 2D it should still look 3D in 3D, and the closer it is the more benefit it will recieve from the added information from S3D too look even better.
Exactly. A huge amount of how we perceive depth in real life is through visual clues such as highlights, shadows, parallax. Games have been relying solely on these tricks to make 3D scenes look 3D on a 2D monitor for decades, and we can judge depth on a 2D screen pretty well already using only these clues.
That's not true for billboard or simple-mesh trees. GT has always got away with simple tree models, but they will look like pieces of flat card stuck together in 3D, if the 3D is at all effective. Like a wardboard cutout of a person. Viewed from a distance it'll look convincing, but up close you know it's flat. Anywhere this gen that flat sprites have been used, such as crowds, will break in 3D if the player can get close enough.
I think it'll be less of an issue in 3D. There's one really obvious (jarring, even) appearance of a 2D tree in the centre of the first tight hairpin on the Indy road course:
Which they even use to get a camera effect looking through the 2D branches:
However, the "2D-ness" of this tree would be reduced in 3D because you would be focusing through the tree rather than relying solely on motion blur to "hide" it.
Looking at a flat object (or in this case, two intersecting flat objects) in 3D is no different to e.g. looking at a road sign as you approach and pass it. I think "billboard" is the wrong word to use as a billboard in 3D graphics is a special case which always directly faces the camera, and is distracting even in 2D. I can't think of a recent game using billboards for scenery, they're only really used nowadays for directionless effects where it doesn't matter, like smoke, or elements which should always be square on to the screen by design, like overlays. If you have something which should vary its appearance depending on the angle you look at it, then billboards break down really quickly (see how ents like dead bodies, candelabras and health kits always face the camera and 'spin' as the camera turns here
http://www.youtube.com/watch?v=yr-lQZzevwA#t=1m7s)
It's actually something of a problem. How do you get convincing 3D trees when they are such costly geometry to do right? I wonder is some sort of randomised displacement in the depth with maybe a second layer of billboard will work?
You can create layers at the expense of an alpha hit, or model them at the expense of a geometry hit. I think for a certain kind of tree, the blurrier you can make them the better, because it hides unnatural polygon edges and also, how can I put this, doesn't give you enough information to see how bad they look! I'm firmly of the opinion that you should do the minimum that works for your game. If you're making a game set in a forest, well, good luck with that
