Make a loop with keyframe

Hello everyone.

So, I was trying to create looping animation using keyframes.

Imagine I’m trying to create a ball moving from left to right and then back to the left in one second. The whole animation is 24 frames, from frame 0 to frame 23. I created two keyframes:

frame 0: Keyframe A - ball at the left
frame 12: Keyframe B - ball at the right

From 0 to 12 (A → B) it moves smoothly, but then stops. Once the timeline reach frame 24 it jumps to 0 and animation start from the beginning.

Is it possible to tell Synfig that it should create in-betweens after frame 12 up to the frame 23 (B → A). I guess I can take a ball at frame 1 and create a copy for the frame 23, but I don’t want to create additional keyframes. Can this loop be done automatically?

Copy the first keyframe to frame 23. Why don’t you want to create an additional keyframe? It’s just one more…

Because if I change the second keyframe B, it will adjust frame 1 a bit, and then I need to copy 1-st frame to 23-rd again, and I need to do that after every change. I though there might be easier way.

No, based on what you are trying to accomplish, you only need three keyframes. For the first keyframe, the ball is to the left; for the second keyframe, the ball is to the right; and the third keyframe is a copy of the first keyframe. If you want the animation to loop throughout the rest of the timeline, just add a Time Loop Layer.

Hm, yes, this works, thank you!
I didn’t know I can create a keyframe on frame 24, but to play animation from frame 0 to 23.