3d sprite

I'm slightly confused about what you are asking because of your terminology.
By 3d sprite do you mean 'animated 3d model?'

I'll try to answer though :)

The 3d sprites in Xenogears are simply multiple 2D sprites that switch when the viewing angle changes above a certain threshold.
You just need a telented artist to do this, no 3d program needed to create the actual sprites. And yes, its a heck of a lot of frames even for a character with few animations. Programming wise it's pretty easy to implement this,
you could have a variable
float horizontalRotation
and float verticalRotation
You round these off depending on how many angles you want on your sprite, then use it to index into the sprites texture.

As for true '3d sprites' you need a mesh editor like blender or milkshape.
Most often people use box modelling (start off with a box and then extrude edges and so on). Then you create textures in a 2d paint program and then you have to map this texture on to your 3d model in the 3d editor.

As for animations on the model common methods to use are:
*Key framing is where you put you model in the extents of its movement and the program blends between the positions. The advantage is that it's easy to do and can have good results depening on the amount of keyframes you specify.

*Skeletal deformation (also called mesh skinning) where you define bones for your model and each bone influences the surrounding vertices, so you can animate your model just by moving a bone. There are many advantages to using this method, for example model data will be smaller and you don't have to preanimate all possible movements - you can implement ragdoll physics using this method.

Thanks

So then each individual frame must be redrawn to the screen as the character moves forward or turns the camera? That seems like an awfull lot of artwork...in order to make the background match the characters turning angle must you include several object positions for all things on the screen? Or do you simply make the character several different sprites and then make the background/environment true 3d? Damn, it seems awfull complicated. How hard of a difficulty would low poly characters in a low poly environment be to do in 3d, the programming side anyways? I want to know for an RPG I am thinking about making a design doc. for, I want to use something that is 3d, has a certain amount of detail but is not extremely hard to program for a decent programming team. Is it best to just pick up an engine somewhere else? Im a writer and 3d artist so the programming side I have no idea.

i have been developing a 2D rpg (still working on the engine), if you want to help. www.the-grid.tk.

Sick of today's game plots

The AI Love Story

genjix at gmail dot com

looks like a good story but I dont know how much I would have to offer, I'm mostly a writer and do some 3d graphics, but you already have writters and they seem to be really good, you are also doing 2d graphics and I only do 3d, ot good at 2d for some reason. Good luck on your game though, great plot.

The term for this rotation of "2d Sprites" is called a 'billboard', I do believe.

You may be able to find some more information by searching google for it.

Even in a 3d game engine, a plane can have the same function.

There is actually something like 3D sprite but it's called: i3D --> image 3D.

It has three dimensional texture maps like 128x128x128 but it's made by voxel -->volumetric pixels.

Houdini support it