Ballistic Trajectory

Ballistic Trajectory tool is used to calculate physically accurate trajectories for characters in the state of free flight. Using it enables  animating convincing-looking jumps, flights and other moves that require your character to get off the ground. Ballistic trajectories can be adjusted somewhat like regular trajectories, but they are created differently and serve different purpose.

Controls

Ballistic trajectory can be created and managed using the dedicated set of buttons on the Timeline:

Ballistic trajectory (1)

Pressing this button adds a ballistic trajectory to the current scene.

Snap centers of mass to selected trajectory (2)

Pressing this button makes the character move so its center of mass is always aligned with the trajectory of the ballistic curve.

For this button to work properly, an interval on the Timeline should be selected beforehand. If you select a part of the interval on the timeline, the center of mass will snap to the curve only on the selected frames.

Set physic priority frame (3)

This button is used to select frames that should be taken into accout for calculating object rotation during  ballistic movement.

A selected frame is marked with a red flag

Multiple frames can be marked at once, but the more positions is used for calculating rotation, the harder it becomes to take them all into account. It is recommended to mark no more than 3 or 4 frames for one ballistic trajectory.

Other two buttons on this panel are for working with Ballistic ghosts: helper object used for creating physically correct rotations for characters in the state of free flight.

Ballistic Ghosts are described in greater detail in the dedicated chapter.

Ballistic ghosts

Pressing this button enables rendering of ballistic ghosts

Snap to ballistic ghosts

Pressing this button alignes character's position with the ballistic ghosts (see the Ballistic Ghosts chapter for more information)

Ballistic Trajectory Structure

Impulse Point (1)

This point controls the impulse that is applied to the object at the start of its ballistic movement. It should coincide with object's center of mass

By moving Impulse point you can adjust every parameter of the ballistic curve: its length, its height, its direction, and its framecount (the number of frames that the object would spend travelling this trajectory)

Note: The length of a ballistic trajectory is represented on the Timeline as a black line

First Frame of Ballistic Curve (2)

This should be the last frame where the object is on the ground

Moving this point adjusts the distance of ballistic movement without changing its framecount

Point of Height (3)

This point defines the maximum height of the ballistic movement (and subsequently its framecount). It can only be move up and down.

Landing Point (4)

The last frame of ballistic movement and the frame where the object touches the ground. This point can be used to adjust the distance of the ballistic movement without affecting its framecount

Grey dots on the ballistic curve represent frames. The current frame is marked with a circle.

 

See Also

Ballistic Ghosts

Fulcrum Points

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