Frame transparency while animating

Development Feature discussions
1

Background:
Back in 1990 Disney made a tool for the Amiga, I think it was called “Disney Animation Studio”. When doing traditional animation the animator flip through each page to match up the animation sequence. This product allowed the animator see a few frames back, and a bit more transparent the further back in time the frame is. See the demo of the tool at youtube.com/watch?v=qSeYivHZpB8

Benefits:
This feature will make some specific animation tasks a little bit easier through fine tuning example - Lipsync, weight placement, direction, eyes, hair.

Feature Concept:

  1. Allow the user to enable a function to see “through” the previous 3 or 5 frames (not layers) before the actual frame. ( default )
  2. Added functionality: Show only keyframes ( checkbox )
  3. Added functionality: Custom frame amount to buffer. ( int )
  4. Added functionality: Custome colour of previous frame ( colour picker )
  5. Added functionality: Select layers to include or exclude from frames ( checklist of layers or extra checkbox in layer manager )
2

To allow such stuff synfig would realy need hardware acceleration for 2D-Vector Graphics, otherwise, i think, it will be to slow to do that.

3

In Synfig it is called Onion skin. It only seems to show the keyframes that are inmediately before and after the current position, though.

Those suggestions would be a good improvement to it though. For example using color to distinguish the “before” and “after” frames would be nice.

In theory, it should also be possible to do this manually by playing around with Duplicate layer and Time offsets. But it’s a lot of work to setup.

EDIT: A quick example using Duplicate layer:

The direction of motion is green->brown->pink->purple->blue (ie. hue is rotating). It makes Synfig slow and the Duplicate layer also has this nasty habit of breaking the display inside Synfig, though. Here’s the sifz file in case you wanna play with it:
http://members.multimania.co.uk/yoyobuae/frame_transparency.sifz

Create some layers inside the “[FrameTransparency]” encapsulation and then animate them to get the effect. Might want to use preview since the viewport doesn’t show things correctly.