jerky lateral movement problem

I am doing an animation tutorial here: My dog’s walk cycle has a jerky lateral movement. I tried decreasing the chest rotation on frames one, twenty-one (copy opposite), and forty-one. I still saw a jerkiness in the movement. I had a jerkiness problem with another animation character, and someone in this forum said I should use the graph editor to fix it. However, I can’t find any tutorials on how to use the graph editor to smooth out the lateral rotation of my dog’s walk cycle. Can someone tell me how to fix the lateral jerkiness of my dog’s walk cycle?

Blend file (modification of chest rotation not included):

in the graph editor tab into edit mode, select the offending control point or points ( keyframe/s ) and hit shift S ( snapping menu ) and select ‘flatten handles’. this may or may not work as expected. another thing you can try is Alt O ( smooth ) which also may or may not work as expected. another option would be to simply adjust those control points manually as if you were adjusting a curve in the 3D window.
(edit) there’s another thing you can try too, which is the ‘clean keyframes’ function, which will smooth things out a bit in a less drastic manner than ‘smooth’, and is hotkey O.

Betcha you can figure out the Graph Editor real easy. Switch the screen from “Default” to “Animation” (using the combo box at the top of the screen). Here you will see an alternate screen-layout which, among other things, shows the Dope Sheet and the Graph Editor one above the other. Click around the Dope Sheet and take a closer look at those Graphs.

What you’ll quickly see is that … they correspond.

Each one of those “dots” in the Action Editor (Dope Sheet) corresponds to a keyframe, which corresponds to a set of vertexes on those curves. Each curve is an F-curve (an “IPO”), which controls one particular variable in a group of related variables. One curve, for instance, might control Z-Location. Point the cursor at the window and hit Ctrl+DownArrow to take a closer look. (Ctrl+UpArrow will take you right back.)

At the end of the day, “those curves” are what actually runs the show. Everything, pretty much, in all of Blender “works that way.” The keyframes (vertices, control-points …) specify exact targets that must be “hit,” and interpolation using F-curves is used for every value “in-between.” You can adjust these curves directly.

You can also play-back your sequence in rough form, but at actual speed (or not …), in order to see what the actual instructions that are being given to Blender are telling it to produce. If the motions, say, of a simple wireframe, are still “jerky,” then you’ll see it, and the Graph Editor will show you curves that are, frame by frame by frame, producing that movement. But, on the other hand, if what you see there is smooth, then it clues you that maybe what you’re dealing with is some kind of playback problem, whereby (for some as-yet unknown reason or another) the computer can’t serve-up a succession of images to you smoothly enough to produce the illusion of continuous motion.

“On the one hand, it’s unfamiliar,” but, “on the other hand, it’s really not that hard to grok what’s going on.” I think that the “ah hah!” moment will actually come fairly quickly, with or without a tutorial.

“F-Curves (IPOs): in the end, it all comes down to this.™”