I'm developing a character animation for a game, but they say that they need a trajectory bone to specify trajectory path of the character. Does any one know how to add Trajectory bone to a character??? If yes, please let me know. I'm using Maya for modeling,rigging & Motion Builder for animation.

You're in the wrong forum. This belongs in the Visual Arts forum.

Usually there is at least one extra bone on a model to define custom functions. For example, an extra bone on the hand to work as an attachment point for weapons... But a trajectory bone i am not familiar with. If they need to workout the trajectory (path of the character) why can't they just use one of the existing bones (like the spine)? If they perhaps need a bone to track a projectile sent by one of the characters, again, why can't they use an existing bone (like the hand)?
I'd ask them to be a bit more specific about their use, and to perhaps rephrase what they need, then report back. As it stands, i too am confused what they're looking for.

The origin of a character is usually the zero point of the model scene. Somewhere in the center of all feet. The hip bone can also be used as another type of orgin - being close to the center of mass and usually the parent of all other bones.

Strictly speaking, any point on the model can show a trajectory. You need to determine what the trajectory's function is.

Quote: Original post by jayawardhan
I'm developing a character animation for a game, but they say that they need a trajectory bone to specify trajectory path of the character. Does any one know how to add Trajectory bone to a character???
If yes, please let me know.

I'm using Maya for modeling,rigging & Motion Builder for animation.

Ive never heard that term before, but I would expect that it is the base/root node of the bone skeleton (usually something near the center of gravity like lower backbone). When you make an animation of say the figure jumping up and down, the entire body moves up and down so the motions is first imparted to the root/base node of the skeleton and from there the corresponding movements of the other body segments are based.

They must mean the root bone, because the root bone is the one that creates trajectories when an object movies as a whole. Typically the pelvis is chosen as a root bone (and it usually happens to be located at 0,0,0 in model space, but that depends). So I guess I would just tell then the name of your root bone (the one all other bones are children to).