Moho Forum

Hello,
I'm making underwater scene, in which when characters speak, the bubbles comes from their mouth and fly upwards. The bubbles should make few smooth movements to left and right while going up. And I need probably few hundreds of these bubbles. And the question is - how to do it quickly? I only know how to make each bubble and give each movement separately, but it would be better if I could make one bubble with programmed movement and then just copy and paste it. Copying bubble with movement is not a problem, but it will appear always in the same spot, and of course characters will stand in various places, so that's a problem. Is it possible to do? Making each bubble and give each movement to each of them will need many hours to finish.
I know that I can use "particle" layer, which "shoots" objects at certain angle, but I would like to add this smooth movement to left and right - is it possible?

Particles in Moho can be animated! Think of this as every particle being a little video clip. I'd try this:
- create a bubble
- animate its horizontal oscillation, starting narrow, then getting wider
- put it into the particle layer, create some ascending movement and let that run.
And the best part:
- you can have many different bubbles/animations in that particle layer, so you can have:
- different sizes
- oscillation starting left or right
- different oscillation frequencies
The particle layer should be bound to the mouth, as Greenlaw says.

You can use a particle emitter parented to a bone attached to the head to align the emitter with the mouth. The direction should be pointing up since that's what bubbles do underwater, and the head's movements should influence how they move from side-to-side. For example...





Here's the demo project...

bubbles.moho

I normally do this type of effect using advanced particle systems in compositing so I can add turbulence and other properties to make the bubbles move more naturally, but this example is fine if you don't need that level of realism.

Another option is to use Follow Path and have some animated bubbles follow the path. This way, you can build in the turbulence effect. To see an example of 'particles' following a path, I made this demo a couple of months ago...

Nachos Demo Project

Hope this helps.

What slowtiger said about animating the particles is correct; done well, this can make the particle motion look more believable. For example, you can add animation in the sprites to simulate turbulence. It wouldn't be physically correct but it might help sell the effect.

Amazing, thank You very much!

Sure, glad that helps.

One thing I should point out: in the project you'll find I added an offset motion directly to the particle layer; this moves the emitter slightly past the mouth drawing at the extremes. If I were doing this for real, I would add a child bone to the mouth bone specifically for offsetting the emitter and animate this child bone instead. This will keep more of my animation keys in one place (the Bones layer,) making it easier to animate and edit.

Whoops! Sorry, I just realized the link to the project file was incorrect. This has been fixed so you can download it now.

No problem, I already figured it out thanks to your description.

One more useful tip:

Moho doesn't allow you to keyframe the Particle properties, however it's still possible switch them off and on as your character speaks underwater. To do this...

1. Set up the child bone as described earlier so you can offset the emitter slightly for more realism. You can remove any existing position keyframes on the particle layer.
2. Keyframe the position of the particle layer at frame 1 and set the interpolation mode of this key to Step.
3. On the frame where the bubbles need to turn off, move the particle layer completely off camera. This will make the particle stream appear to turn off without erasing the particles that have already emitted (assuming you have the Free-Floating option enabled.) This is a cheat because the particles are actually still emitting, it's just doing this off-screen.
4. To turn the particle emission back on, position the layer back over the mouth. You can simply copy/paste the frame 1 keyframe for this.

Now you can have the bubbles emit when the character opens his mouth and stop when the character closes his mouth.

If you want to get clever about this, make a Smart Bone Dial to move the particle layer off- and on-screen. Just remember to use Linear keys for the Smart Bone's rotation inside the Smart Bone Action (set this mode at frame 1), and use Step keys to move the particle layer. When you're animating the Smart Bone Dial on the Mainline, use Step keys. (I just now tried this trick in the demo project and it works fine.)

Here's the version with the on/off switch...

bubblesOnOffSwitch.moho

Note: Actually, I didn't bother with step one in my example file. It's just a good idea in practice.

Maybe because I'm working in AS 11.2 my options may be limited, but I created a bubble sequence that emit from a characters underwater movement. I've not been able to get the particle layer to move with the character in the animation.

On frame 0 I can move the particle layer's position with the Transform Layer tool no problem, but not on the actual timeline. It remains anchored to it's placement wherever it exists on frame 0.

At first I had it as an independent particle layer behind the character for ease, but when that didn't work, I nested it in the character and bound it to the parent bone. Still failed, so I created a child bone, bound the particle layer to it, but the particle layer still remains anchored in it's frame 0 position and will not move with the character.

I'm basically trying to do what Greenlaw's demo does with the bubbles following the mouth, but in my my case I utterly failed and the bubbles source location remains static.

Any help would be much appreciated

Even in 11.2, you should be able to bind a particle layer to a bone to move and rotate it.

synthsin75 wrote: ↑Mon Jul 01, 2024 11:40 pm Even in 11.2, you should be able to bind a particle layer to a bone to move and rotate it.

It will bind to a bone and works perfectly on frame 0...but when in the timeline there's no responsiveness and it just stays fixed in place with the particle source no longer moving with the bone, and I can't manually animate it by simply using the Transform Layer tool either. I'm wondering if I have a setting that's preventing the source from moving in the Particle Options??

I'm stumped

Do you have any animation channels muted or something?

My original reply before solving the issue (I have to plead ignorance....I don't know how or where to mute a channel, I've never been aware of that function in the software)


Good news!!!!! I just fixed it!!! Woohoo!!!! I had the "Free Floating" box checked which made it independent from my rig!!

Thanks for your replies, much appreciated as always

Ah, glad you figured it out.