Inbetween frames created by setting the inbetweens value are only visible when playing or exporting the animation and are not visible in the timeline. This simplifies the timeline and uses less memory. However, you can expand an inbetweened sequence so that its inbetween frames get added to the timeline. The original key frames will have their inbetweens values set back to 0 so that the resulting animation will be the same when played.
This may be useful for a number of reasons such as having the ability to make changes to the inbetweened sequences that would not be possible using inbetweening alone.
Add inbetweened frames to the timeline by selecting at least one key frame in the timeline that has a inbetweens value set > 0 and clicking 'Add Selected Inbetweens to Timeline' in the Edit menu. This will only be enabled if an inbetweened key frame has been selected. Note that this action cannot be undone, so it may be wise to save first and check that the result is as expected before saving again.
The timeline before and after using 'Add Selected Inbetweens to Timeline'
All frames were first selected by using the Shift key. Auto-Easing is enabled.
Multi-Selecting frames with Auto-Easing
When adding frames to the timeline, the program only uses information from the selected frames. This means that if you only select one inbetweened key frame then the resulting generated frames will not be eased even if the frame is in a group of multiple inbetweened key frames and Auto-Easing is enabled.
For this reason It is important to select all key frames in a group of multiple consecutive inbetweened frames before using the 'Add Inbetweened Frames to Timeline' feature if you want the resulting movements to not change when auto-easing is enabled.
Select multiple frames by using the Shift key while clicking frames or by using the 'Multi Select' option in the right click menu.
Inbetweening Between the Newly Generated Key Frames with a Background Fade
The newly generated frames can now be treated as key frames and new inbetweens can be created between them if needed. However, with regards to background inbetweening, it should be noted that a frame cannot contain a blend of more than two backgrounds. If a newly generated key frame already contains a fade between two backgrounds, then you cannot fade between that key frame and a key frame containing a 3rd background in the expected way. One of the background images will be lost.
