Function curves

[Simon Edmondson]

I've reached the point were I need to learn how to use the function curves to edit the ease in and out after the keys have been set. This is something avoided for a long time but, have to learn some time.

 

I have a figure hitting a tree top and that then bends down with the weight and force of impact. It bends over to the point were its going to snap back and launch him upwards. I'm reasonably happy with the keys but would like to adjust the curves so that there is a chance for the facial expressions to read.

 

There are five bones on the tree. If I open up the graph editor which are the axis that I need to edit, x, y, or Z and what is it that needs to be adjusted ?

If the curve going through the key is steep in and rounded out, does that mean its fast in and slow out

 

I appreciate this may be a 'piece of string' type question but, these are the curves before editing ?

Any help gratefully received. Thank you.

regards

simon

[robcat2075]

My

will give you some general info.

 

 

 

 

There are five bones on the tree. If I open up the graph editor which are the axis that I need to edit, x, y, or Z and what is it that needs to be adjusted ?

 

It looks like you've been rotating the bone mostly along one axis and that's why one curve (the red) is most curvy.

 

You can edit the shape of those curve much like you can edit splines in the modeler. Turning on "Show Bias handles" works in this curve editor for adjusting the slope thru a CP.

 

You can also experiment with an edit by grabbing a PC, sliding it up and down and observing how that changes the bone in the animation.

 

The reverse also works. You can move the bone in the animation window and see how that changes the curves.

 

 

 

 

If the curve going through the key is steep in and rounded out, does that mean its fast in and slow out

 

basically , yes.

 

steep lines mean the value is changing fast and not-steep lines mean the value is not changing much. The actual numbers aren't too important, the steepness/flatness is.

 

 

Note that the window typically only shows curves for what is selected. You have one bone selected so only the curves for one bone show. You can CTRL-select several bones to make curves for several of them display if you want to study several or grab and move their keys together.

[robcat2075]

On your tree... it looks like you have the bias of the splines that run vertically up the tree trunk set to some large value and that is what is making it not bend smoothly.

[Rodney]

In order to really see what is going on you might have to share a project file.

Ease (Slow In/Slow Out) is mostly just a matter of increasing/decreasing the spacing of an object or character so that an effect of acceleration/deceleration is generated.

 

I still think the easiest way to get that face up close to the camera is to cheat it but you can do it manually or through adjusted focal distance or a combination of all three approaches.

 

But back to your question... concerning Ease in the Timeline.

 

If you have seven keyframes then you would likely stagger them out.

12.3..4..5.67 (This would be a slow in/slow out)

1.2..3...4....5.....6......7 (This would be a slow out)

1......2.....3....4...5..6.7 (This would be a slow in)

 

If you consider the entire motion of the tree moving down under weight and then launching upward that a reversal of the slow in/slow out:

 

1...2..3.4.5..6...7 (The center keyframes 3, 4 and 5 would be where the characters face delays just in front of the camera)

 

Because of A:M's splinebased animation you might be able to accomplish this with only two keyframes and by stretching out the arc's tangent.

 

Let me see if I can draft up a quick animation...

[Simon Edmondson]

On your tree... it looks like you have the bias of the splines that run vertically up the tree trunk set to some large value and that is what is making it not bend smoothly.

 

Robert

Thank you for this reply and the one above it. Before I get onto curve editing, could I ask what you mean by the values on the splines, are you referring to the gamma values ? ( thats not something I've ever known about or understood really ). When I was modelling the trees I just extruded the different spline rings, then scaled them in the x/z axis and did not set any gamma values, leastways thats rthe memory but it was a few months ago so could be mistaken,

regards

simon

[Simon Edmondson]

...

But back to your question... concerning Ease in the Timeline.

 

If you have seven keyframes then you would likely stagger them out.

12.3..4..5.67 (This would be a slow in/slow out)

1.2..3...4....5.....6......7 (This would be a slow out)

1......2.....3....4...5..6.7 (This would be a slow in)

 

If you consider the entire motion of the tree moving down under weight and then launching upward that a reversal of the slow in/slow out:

 

1...2..3.4.5..6...7 (The center keyframes 3, 4 and 5 would be where the characters face delays just in front of the camera)

 

Because of A:M's splinebased animation you might be able to accomplish this with only two keyframes and by stretching out the arc's tangent.

 

Let me see if I can draft up a quick animation...

 

 

Rodney

Thank you for your reply and particularly for the video. There is much to digest there and I will try this afternoon.

Is the method you describe above analogous with the system drawn animators use when they put tick marks on the exposure sheet ?

I've not used it myself bu have read about it a bit and seen it demonstrated.

regards

simon

[robcat2075]

could I ask what you mean by the values on the splines, are you referring to the gamma values ?

 

In this case I'm talking about the bias>magnitude. Alpha and gamma are like a twist in the direction of the spline through the CP. Magnitude is like a stiffness of the spline as it goes through the CP

 

Here are three copies of a spline that is bent like your tree. The magnitude of the CPs on the top have the default 100%. The second one has a higher magnitude, it looks lumpy, like your tree. The third one has a low magnitude, it has sharper corners.

 

 

Magnitude has separate In and Out values. You don't know which side is In or Out until you try.

 

You can change a bias directly with the bias handle or by numbers in the Properites.

You can change several selected CPs at once with either method.

[Simon Edmondson]

Robert

Thank you for your reply. I followed your suggestion and looked at the magnitude values and both the in and out were set to 100% on both the horizontal and vertical splines so I had a look at the cp weightings instead and got the following result.

Thank you for your help.

regards

simon

 

[robcat2075]

that looks better!

[Rodney]

Is the method you describe above analogous with the system drawn animators use when they put tick marks on the exposure sheet ?

 

It is. Both the Timing Charts you'll see on the Extremes (Key Poses) as well as the breakdowns on the Exposure Sheets (xsheets).

The same thing is accomplished in CG but generally the computer is doing all that stuff behind the scenes.

The problem with this is that when we let the computer do the inbetweens (which it always will unless we use stepped/held keyframes or tell it to do otherwise) we get a very mechanical result in our animation. Unless we specifically are looking for a mechanical result this is rarely a good thing.

 

 

There is a really simple exercise that will demonstrate Ease and that is to set up a ball (or other object) and set to key positions.

(for demo purposes I like to create these on frames 1 and 2)

Frame 1 is the initial Extreme and Frame 2 is the final Extreme. These two 'keyframes' are your storytelling poses/frames.

 

With Frames 1 and 2 in place, then move frame 2 to frame 3... which then leaves an automatically generated (but unkeyed) inbetween on frame 2 in between. Keying frame 2 then gives you a mechanically generated Inbetween exactly between Frames 1 and 2 that can be altered/manipulated as a Breakdown. It is this Breakdown that will dictate the Favoring or Ease of the motion from frame 1 to frame 3. This Breakdown is the sequences primary performance Extreme. You can then spread this three frame sequence out to the desired time and create additional Breakdowns if/as necessary.