Stroke exposure animation

[Pesto]

Hi all,

I wanted to create an animated stroke so I was using the stroke exposure feature. When I keyframe it it does not show up in the motion graph. Is that normal?

Since it didn't show up in the motion graph I created a bone dial to animate it so I could control the animation in the motion graph. The only issue is the animation is not very smooth when I alter the bezier handles. Any suggestions?

Thanks!

[Greenlaw]

Oh, interesting...I've been using Moho in production for years and I never noticed that Stroke Exposure doesn't appear in the Graph Editor.

To be honest, I hardly ever use the Graph Editor in Moho, at least I don't use it nearly as much as I do in After Effects or in a 3D animation program. The reason is because the interpolation modes available in the Timeline usually do what I need.

Setting up a Smart Bone Dial is a good way to control velocity in an animation. If it's not playing smoothly, make sure you have enough frames in your action. Moho plays back the Smart Bone animation in whole frames (i.e., no interpolated in-betweens,) so if you don't have enough frames in the action, the animation can stutter when it's slowed down. The ideal number of frames depend on the complexity of the animation and just how slow you intend to play it back. Some of my actions may be only a few frames long and others may run several hundred frames (fully head and body turns for example.)

Also, set a key at frame 1 and set that to Linear, and then use Linear keys throughout the Smart Bone Action. You want the animation to run at a constant speed inside the Smart Bone Action; you can vary the speed or add eases to Smart Bone Dial on the Mainline.

Frame 0's Interpolation mode should be set to whichever mode you want to use for that Smart Bone Dial in the Mainline. (I usually leave this set to Smooth.) If you set the default Interpolation mode to Copy Previous Key, the Mainline will default new keyframes to whichever mode you set at frame 0 or the previous keyframe. Note: Copy Previous Key makes the Timeline behave like After Effect's Timeline, where you're not constantly having to change the interpolation modes.

Hope this helps.

[Pesto]

Thank you very much for the great explanation. I think my problem was I didn't have enough frames in the Smart Bone Dial.

I also think I need to read up on the graph editor and the interpolation modes a bit so thanks again for all the info!

[Greenlaw]

Sure, glad to help.

A good exercise is to make a simple animation and render it, and then try switching the interpolation modes to see how they affect the animation. It's fun to see this in a character but doing this with a simple bouncing ball animation might actually be more informative.

One thing that new users may find confusing is that the interpolation modes affect the outgoing side of a keyframe to the incoming side of the next keyframe. I think Smooth is the one exception where both sides of the keyframe are 'smoothed'. (Actually, I'm not 100% sure about that...let me check.)

Anyway, Smooth is the mode I use the most in Moho, even when I'm holding a keyframe. (I only use Step keys when I want a 'steppy' looking animation.) There are two ways to hold a Smooth key: 1.) Alt-Click drag the key to stretch it for the duration of the hold or 2.) copy and paste the key to later frame where you want to end the hold. I prefer the latter because it's less fiddly and easier to edit, especially when you're editing multiple selected items (like bones) at the same time.

[slowtiger]

Layer animation gives you a nice preview of the positions between keys, so I just took some screenshots. Last frame (100) set to step, first frame set to indicated. If we trust Moho that these represent the real interpolated positions, we find that:
Smooth appears to be non-symmetrical.
Ease in/out has a greater accelleration than smooth.
Ease out seems to be identical with Ease in/out (this bothers me for years now).

[ggoblin]

Thank you Presto for your neat workaround for the absence of Stroke exposure in the motion graph.

http://www.lostmarble.com/forum/viewtop ... 71#p204671

[ggoblin]

According to the motion graph there is a difference between the Ease in/Ease out and Ease out curves, a very slight difference.

Also both Smooth and Ease In/Ease Out curves look symetrical, though I might be wrong.

Apologies for the screen shot, would be clearer if each curve was a different colour.

[Greenlaw]

That seems like a good setup. Thanks for sharing Slowtiger.

[Greenlaw]

Smooth behaves differently from the Ease modes. I'm not completely sure about this but I think Smooth dynamically smooths the motion. That might sound vague but here's what I've observed...

1. When the object is starting or stopping at the keyframe, there is an automatic ease applied to the outgoing or incoming side of the key.
2. When the object is already in motion before the keyframe and continuing to move after the keyframe, then there is little to no easing applied.

I think this adaptability is why Smooth seems to work well for general character keyframing. For the most part, you just set it and forget it.

The Ease modes are more traditional and not so great for general character animation because they don't automatically adapt to what the character is doing. But they're behavior is more or less predictable when you're doing basic transforms with an object. So they're most useful when when they do is exactly what you want.

I really should take the time to re-examine these modes to make sure I fully understand how they work within Moho's environment. I grown so used to using only Smooth, Linear, Cycle, and occasionally Step, because they're predictable and pretty much cover everything I need.

[slowtiger]

Yes, that's exactly the same combo I use. In most cases it's good enogh, if I need some refinement, I just create another key.

However, doing complex camera moves or zooms are something different. No matter what I try, the default interpolation is not even near my intentions.

[SuperSGL]

Ease out seems to be identical with Ease in/out (this bothers me for years now).

I'm glad you posted that, that was driving me nuts ( although considering it's still gonna) but at least I know I wasn't setting it up wrong

[Daxel]

Smooth behaves differently from the Ease modes. I'm not completely sure about this but I think Smooth dynamically smooths the motion.

Yes, I am testing it and the context of the smooth keyframe not only dynamically affects the timing of the interpolation but also the trajectory of the element, that curves. This contextual adaptation happens with the ease in and the ease out keyframes too, but not with the ease in/out keyframes or any other kind of keyframe , for them the timing and the trajectory remains the same no matter the context.

Yeah I also feel like I would appreciate some more information about how these interpolation modes work and their intended use.