You can use the following keyboard shortcuts for keyframing in MotionBuilder.
| Action | Keyboard Shortcut |
|---|---|
| Add keyframe | S |
| Add Zero keyframe | Shift-S |
| Add Flat keyframe | Alt-S |
| Go to next keyframe | . (period) |
| Go to previous keyframe | , (comma) |
| Key at Time x | Ctrl-Shift-S |