Ballistic Ghosts

Ballistic Ghosts is a dedicated tool for working with character rotation in a state of free flight. These silhouettes show presumed physically correct positions of your character in mid-air. Positions are calculated on the basis of character's angular momentum, as well as the poses set for the character in the keyframes.

By using Ballistic Ghosts you can make mid-air animations look much more realistic without spending a lot of time manually refining each frame.

This instrument is controlled by the following buttons on the Toolbar:

(1) Ballistic ghosts
This button enables the ballistic ghosts.
The instrument tries to take into account poses of the character in the keyframes, but this might sometimes lead to situations where physically accurate positions are impossible. In such cases, some of the poses might be ignored.

By default, the first and the last pose on the ballistic trajectory are considered the most important.
If one of the in-between poses of the character is deemed important, mark it. Now, when you alter this pose, ballistic ghosts will be recalculated so the character would go through the newly altered pose.

Note

You can mark several poses, but the more poses you mark the harder it is for the program to take them all into account. Marking more than four poses is not advised.

(2) Snap to ballistic ghosts
Pressing this button aligns character's position with the ballistic ghosts.

(3) Set physics priority frame
This button selects frames that should be taken into account for calculating the object’s rotation during ballistic movement.
A selected frame is marked with a red flag
Multiple frames can be marked at once, but the more positions are 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.

The way Ballistic Ghost work is also affected by a number of settings available in the Settings Window:

ValuableFramesWeight
Defines the weight for priority frames. Increasing this value means less changes would be made to the priority frames, but more changes would be made to the rest of the frames.
Set to 200 by default.

WeightAngleRotations
Controls the extent to which rotation is preserved. Increasing this value means less changes are made to the object's rotation.
Its default value is 1.

WeightAngularVelocity
Controls the extent to which the rotation axis is preserved.
Its default value is also 1.

WeighLastFrameRotation
Controls the extent to which rotation on the last frame is preserved.
By default, it is set to 200.

 

If Ballistic Ghosts are not visible in the scene, you'll need to snap the character mesh to the Center of Mass. To do this:

1. Switch to the Mesh Mode.

2. Select the mesh.

3. Switch to the Point Controller Mode.

4. Select the center of mass.

5. Select Center of mass →​ Snap mesh to the center of mass from the Commands menu:

 

See Also

Ballistic Trajectory

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