Animating in Flame – P8 – Extrapolating & “Baking” the curve – Flame 2020.3


Hi everyone, Grant for the Flame Learning Channel. In previous videos, you’ve been learning all about keyframes… And creating animation on a curve. In part 8 of the animation series… You’ll learn how to manage your animation… beyond the keyframes and the curve. This is called Extrapolation… And you can do various operations… Like repeating animation, reversing looping an animation… Or simply keep the animation travelling in a linear direction. You’ll also be baking the extrapolations… Which converts them into editable keyframes. This is very handy… If you want to create repetitive animation… And then tweak the keyframes. If you’d like to follow along… Import a graphic… And animate the Y position channel from frame 1 to frame 10. So during this 100-frame composite… You have an animation over 10 frames… And nothing else. If you have framed your animation to the window… Zoom out and pan the view to show the entire 100 frames Now whatever happens before the first keyframe… And after the last keyframe… is known as extrapolation. By default, this is set to CONSTANT. This means, that before the animation begins… and after the animation ends… the value of the keyframe is constant. This is why you see the flat line. To change the behaviour before and after the main animation… Go to the extrapolation pulldown menu… And change it from CONSTANT to CYCLE. When you play the animation… It is repeated every 10 frames. Now this extrapolation is dynamic. If you were to make any changes to the animation curve… The extrapolated curves would update with the changes. So for testing and trying out repetitive animation… This is very interactive… Without having to resort to a mathematical expression. If you change the Extrapolation to REVERSE + CYCLE… The curve keeps reversing itself… in each cycle of the extrapolation. Really handy for bouncing graphics etc. Now if you manipulate the tangents of a keyframe… You can see how you can completely change the outcome of the extrapolated animation. Now the tangents also play a role… When you use the last extrapolation mode. Change the mode to LINEAR. Now if your tangents are horizontal… The expected behaviour matches CONSTANT… Because the tangents maintain a consistent value. However, when you start adjusting the tangents… The curve will be projected on a linear curve. In artistic terms, the object will continue animating in the same direction. One practical use case… is if you’re tracking an object… and it’s meant to go off-screen… you can continue its trajectory… even if you can’t generate tracking data as it moves off screen. So these extrapolation modes… can definitely enhance and accelerate experimentation and creativity. I’ll switch the extrapolation back to REVERSE AND CYCLE. Now it’s worth pointing out… That the extrapolated animation… goes to the end of the 100 frame composite. However since the actual animation curve… only exists between frame 1 and frame 10… You currently cannot make any changes to the animation curve beyond frame 10. In order to convert the extrapolated part of the curve into something editable… You need to “bake” the curve. Go to the Keyframe menu… And open the Curve Functions. We’ll be coming back to a lot of these in later videos… But for now, choose BAKE. Looking at the animation curve… The extrapolated region has now been converted into keyframes… And you have one keyframe per frame… In order to maintain the exact look of the curve. Very importantly… Only the portion of the extrapolation… that falls within the duration of the 100 frame composite. Will be converted to keyframes. Anything outside this region will still use the original extrapolation setting. To illustrate this… Set the Extrapolation back to CONSTANT. Now even though the curve is editable… I wouldn’t call this a completely useable state. So next to the Bake option… Start dragging the curve value… Which will reduce the number of keyframes in the baked portion of the curve. As you drag to the right… The curve will eventually get to the least amount of keyframes… to maintain its shape. It will not degrade any further using the BAKE curve function. So now that you have a totally editable curve… You can go ahead and tweak the keyframes to reduce the bounce over time. I am doing this manually… But you could also combine this curve with an expression… To make the animation smoother. Check out the expression series if that interests you. So moving on from this… In the next video… You’ll start looking at some of the other math operations… With Curve Functions. This will help with operations… such as reversing keyframes and more. Comments, feedback and suggestions are always welcome and appreciated. Please subscribe to the Flame Learning Channel… And click the bell to be notified for future videos. Thanks for watching… and hope to see you soon.

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