display every other frame

Support Compositing and Post Processing
1

I’m mostly using Blender as an compositor for 2D animation done in other applications, imported as image sequences in Blender.

For some scenes I’ve created animated elements in Blender, compositing these together with the 2D stuff.

Now much of the 2Danimation is done on twos which makes the Blender animation much too smooth in the mix.
How can I display every other frame of the blender animation in the comp?

I’ve tried a few approached but haven’t succeded with any of them:

  • Rendering Blender animation to image sequence and manually removing every other frame, then using this sequence in compositor. Hoping to be able to change fps or clip length to twice to match length of comp. Havent found a way to change clip length/speed in compositor. Is there no way!?
  • Using the above image sequence, removing every other frame, then manually duplicating the rest and renaming these so there is a full length sequence with two alike frames every other frame. This gives me the result I’m after but is way to cumbersome.
  • Setting a keyframe every 2 frames in the animation and then making these stepped. Works but a nightmare if I want to edit the animation.

How can I use a clip in composition with half of the frames showing? (Scaling clip to half length, then scaling this to double length perhaps?)

2

If you bring in all the images and then change the render range step value to 2 it may render every other frame.
http://wiki.blender.org/index.php/Doc:2.5/Manual/Render/Output_Options#Dimensions

3

Thanks. I’ll try that next.

For now I figured out I can use the NLA editor, turn the animation into an action and adding a stepped modifier. This works, BUT, now I can’t see and edit the keyframes. Animation is there, keyframes is not.
I’ve named the action but with Dope Sheet set to action editor the stepped action is not in the list of actions. What is wrong?
I can’t find any good documetation on the NLA editor, does it exist somewhere? (I mean more than just a description of the functions or tutorials on how to cycle a walk. Need a little more in-depth tutorial)