Dev:Ref/Release Notes/2.79/GPencil

= Grease Pencil =

Interpolation Operators
Two new operators were added for interpolating between a pair of Grease Pencil frames:
 * Interpolate (Shortcut Ctrl+Alt+E) - This is equivalent to the Breakdowner tool for armatures. It allows you to interactively pick an new sketch interpolate from the neighbouring sketches
 * Sequence (Shortcut Ctrl+Shift+E)- This fills the space between a pair of Grease Pencil frames with interpolated frames. It is equivalent to the Sample tool in the Dope Sheet Editor

To use these operators, there need to be Grease Pencil frames on both sides of the current frame. (Also, note that the current frame cannot be on one of the frames that the interpolation is occurring between).

It is possible to control how the Interpolate Sequence tool blends between the two frames using the options under Sequence Options. There are 3 basic types of options:
 * 1) Linear - By default, the Sequence operator will perform Linear Interpolation. That is, it smoothly interpolates between the two frames at a constant rate.
 * 2) Easing Equations - The Robert Penner easing equations (and associated controls) can also be used to control the interpolation speed/shape, just like for F-Curves/Keyframes.
 * 3) Custom Curve - It is also possible to define a custom curve to get more fine-grained control over the interpolation using a curve-map widget.

To make it easier to fine-tune the interpolation, there's also a new operator, Remove Breakdowns, which can be used to get rid of the newly generated "breakdown" keyframes (i.e. the small blue ones).

All these operators and options can be found in the toolshelf under the "Interpolate" panel (between Edit Strokes and Sculpt Strokes).

Other Improvements

 * Per-layer option to always show onion skinning. Sometimes it can be useful to be able to keep onion skins visible in the OpenGL renders and/or when doing animation playback. This option can be found as the small "camera" toggle between the "Use Onion Skinning" and "Use Custom Colors" options. There are two use cases where this is quite useful:
 * For creating a cheap motion-blur effect, especially when the before/after values are also animated.
 * If you've animated a shot with onion skinning enabled, the poses may end up looking odd if the ghosts are not shown (as you may have been accounting for the ghosts when making the compositions).
 * Add Blank Frame (Shortcut D+B). This operator adds a new frame with nothing in it on the current frame. If there is already a frame there, all existing frames are shifted one frame later.
 * Numpad keys now work when doing sculpt sessions.
 * Tools in 3D View menus. Previously, many of these were only available in the tool shelf or pie menus.
 * Reproject Strokes option to project strokes onto geometry, instead of only doing this in a planar (i.e. parallel to viewplane) way.