【High-Quality Live2D Guide for Beginners】 Eye Physics① (Patreon)

Hello everyone! This is Kanbutsu Himono.

Sorry for the slight delay in posting, but I’ll continue with the beginner-friendly Live2D course!

Last time, we finally wrapped up the topic of eyelash deformation.

https://www.patreon.com/posts/high-quality-for-135146927?utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=postshare_creator&utm_content=join_link

Today, I’ll move on to the next part: eye physics!First, here’s the finished sample video:

https://drive.google.com/file/d/1JCvs5OpMcCXza52QnjvAddGTUE8TVhUS/view?usp=sharing

Isn’t it adorable how the eyes look glossy and tremble slightly? ✨

You can see the pupils contracting in sync with blinking, as well as the highlights and reflections shaking!

This kind of feature, where one movement automatically drives another part, is called Physics!At its simplest, you can use it to make hair or clothes sway... But if you push it further, you can correct angle deformations for the face, spin swords around, or even make the way something shakes change depending on a toggle.It’s the kind of effect that makes you wonder, “Is this magic?”

Of course, it’s also a complex feature that’s easy to get lost in, so I’ll go through it slowly. Take your time and follow along at your own pace!

By the way, I distributed the eye physics cmo3 file separately last month:

https://www.patreon.com/posts/cmo3-2025-latest-136074018?utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=postshare_creator&utm_content=join_link

Be sure to check out that file as you work through this too ✨

Also, if you’re a YouTube membership subscriber, you can watch the production process in video form:

https://youtu.be/C6gEizVoYZs

That said, if the articles alone are enough for you, there’s no need to force yourself to watch the YouTube content!Study in whatever way works best for you 🥰

------------------------------------------------------------------------------------------------------

Table of Contents

[Optional] Organize parameters into folders

[Essential] Rename parameters

[Optional] Create new parameters

[Optional] What is a Blend Shape?

[Optional] Creating highlight “flower” sway

Bonus: How to check which parameters are linked to an object

Tip: Press Ctrl+F (or Command+F) and type the section titles above to quickly jump to them!

Note: I personally don’t think beginners need to force themselves to create physics for eyelashes, so I’ve marked all physics-related steps as optional.If you’re not planning to use physics at all, you can basically skip this entire article lol.

------------------------------------------------------------------------------------------------------------

[Optional] Organize Parameters into Folders

If this feels like too much hassle, feel free to skip it.From here on, the number of parameters will increase at an incredible pace, so to avoid confusion, let’s create folders and group them by purpose!

You can create a folder by right-clicking in the Parameter Palette → “Create Folder,”or by clicking the folder icon in the bottom-right corner.

Once created, folders are automatically named “Folder1,” “Folder2,” and so on.Double-click the folder name to rename it.

You can also drag to move the folder’s position, and drag parameters into the folder to organize them. Of course, you can also take them back out.

https://drive.google.com/file/d/1dWlx7pBFbfTbEkzwqymXECJOGioOQKTa/view?usp=sharing

You may notice some symbols attached to the folders.I briefly explained this before in the article 【High-Quality Live2D Guide for Beginners】 ①-3 Bonus Section

(To make it easier to jump with Ctrl+F, I’ve added a Table of Contents to each article. In that article, search for "Bonus Section ③: Why I Add Symbols to Parameter Names～" to jump straight to the relevant part.)

To summarize the naming convention:

Names with “〇” = parameters driven by tracking

Names with “★” = parameters driven by physics

“◆” = for physics correction

“◇” = for toggles or animations

“▽” = for blend shapes

By dividing parameters with these symbols, I can tell at a glance what each parameter is used for.

This time, let’s create these three folders:Following the above symbol rules, that gives us:

〇Angle = angle-related parameters driven by tracking

〇Eye = eye-related parameters driven by tracking

★Eye = eye-related parameters driven by physics

We’ll decide what goes inside later, so for now just make the folders.

By the way, I don’t personally use it, but you can also give folders a label color.It makes them really stand out, so it’s even easier to keep things organized. Try it if you’d like!

https://drive.google.com/file/d/1VXg50XpoBk3SWzm2GnG45jR9Oq6dZrtg/view?usp=sharing

[Essential] Rename Parameters

Technically this could be optional too, but if you skip it you’ll almost certainly get confused later when working with physics.Even if you don’t use physics, the names alone can get messy, so I’m marking this step as Essential.

First, take the default angle parameters (Angle X, Angle Y, Angle Z) and add “〇” to their names.

From this...

To this!

If you’ve already created the “〇Angle” folder in the previous step, go ahead and throw them in there too.

Later on, we’ll be making parameters like “★Angle X” for physics or “◆Angle X Bounce” for bound parameter, so if you don’t rename them here, you’ll end up in total chaos lol.

Next, let’s rename the eye-related parameters by adding “〇” and placing them into the “〇Eye” folder!If you’ve been following this tutorial, you’ve probably noticed that most of my screenshots already show parameters with “〇,” so many of you may have already renamed them by now lol.

For example, “〇Smile” is the parameter we created by merging the left and right smile parameters in the article Eyelash Deformation②.

https://www.patreon.com/posts/129004125

Since that merging step was optional, if you’re still keeping the left and right smile parameters separate, just add “〇” to each of them and drop them into the folder.

Finally, let’s clean up the eyebrow parameters.

By default, there are rather many eyebrow parameters.

But honestly, with tracking you won’t be able to fully make use of so many.So let’s reduce them.

Much cleaner ✨Here’s what I did:

Deleted the “Left/Right” parameters entirely

Optionally merged left and right for “Up/Down” and “Deform”

Added “★” to the angle-related ones, and “〇” to the up/down and deform ones

Later, we’ll also be making parameters like “〇Left Eyebrow Angle,” but for now, let’s leave those aside.

Eyebrows can be made in many different ways, so you don’t need to copy me exactly.But if you do, you’ll probably end up with eyebrows that give much more expressive movement—so please look forward to that!

https://drive.google.com/file/d/1KUT1Icsb-sCDGKLMg2gqLyJXkpRNszBg/view?usp=sharing

↑ These are eyebrows I made a few years ago using almost the same structure.

※ By the way, I actually forgot to create a “〇Brows” folder in both the distributed cmo3 file and the membership videos. Ideally, you should also make that folder and put all your edited eyebrow parameters inside it. If you have the time, go ahead and do that first… lol

-----------------------------------------------------------------------------------------------

[Optional] Create new parameters

Sorry for dragging out the parameter talk, but we’ve got one more round to go.From here, we’ll be creating quite a few new parameters.They’re mainly for making expressions richer or for giving the eyes a jiggly, shimmering effect, so if you don’t need that, feel free to skip this section entirely.

First, let’s add four new “〇Eye” parameters.

↑ You’ll notice the parameter IDs end with a “T.”That stands for Tracking.Later, we’ll also create parameters like “★Smile Eye Shape,” so I’m using the “T” here to keep things distinct.

↑ Nothing special to note here. Just make them as shown.

↑ For 〇EyeBallX, make sure to check the box for Blend Shape.We’ll be using Blend Shape a lot in this article—it’s a super-powerful, incredibly convenient function. For now, just remember it as that! I’ll explain in detail in the next section.

Next, let’s make 〇EyeBallY.Here we can try out the Replicate Parameters function.

https://drive.google.com/file/d/1tRaHE9nALczSiGGGNDVR6FTxRoHHXIFQ/view?usp=sharing

Right-click on 〇EyeBallX → Replicate Parameter→ A new one appears called 〇EyeBallX2 (same structure, just the name/ID gets a number at the end).Then, simply repurpose that to make 〇EyeBallY.

This way, it’s much easier than creating it entirely from scratch!And since we’ll be making a lot of similarly named physics parameters later, you’ll want to use this replication trick whenever possible to save time.

Now, let’s move on to the “★Eye” parameter.

Yeah, there’s a lot… sorry lol.But every single one of these needs to have Blend Shape enabled, so don’t forget to check that box.For the ones with numbers like “1” or “2,” just use the replicate function—it’ll take only seconds to make them.I’ve included all the IDs for reference, too.

That’s it for all the new parameters!Preparation complete! 🎉

-------------------------------------------------------------------------------------------

[Optional] What is a Blend Shape?

Now then, let’s talk about the ultra-handy, god-tier function: Blend Shape.If you already know this, feel free to skip ahead.

In short, Blend Shape is a feature that automatically combines multiple deformations.

Here’s what that means:Normally, if you link more than two parameters to an object, the combined motion isn’t automatically created.

For example—say you want your character to roll their head around in circles, like this:

https://drive.google.com/file/d/1AFWHj8qOXkrPC41glbPiYQlvR3rScoe-/view?usp=sharing

To make this, a common approach is to use two parameters: one for up-down movement, and another for left-right.

https://drive.google.com/file/d/1cDVK2x9DHDMg7f3k1yPrbt3KdO4lv5qE/view?usp=sharing

But if you just leave it at that, the motion becomes awkward whenever both parameters are set to a non-zero value.That combined movement often needs manual adjustment.We usually call this kind of thing the “combined movement.”

https://drive.google.com/file/d/1PX3E7IOYI5dIubUMESl6NXMdMu1iYcTh/view?usp=sharing

※ By the way, in case you forgot: to link two parameters together, just click the button to the left of the parameter names. (We covered this in the previous article!)

https://drive.google.com/file/d/15uchXKcZDE-oZnbePRYpX6gIa4nxRESF/view?usp=sharing

And here’s the key difference!!Unlike regular parameters, Blend Shape automatically generates those combined movements for you.No extra tweaking needed!

https://drive.google.com/file/d/1b6emjvqL2Qc4ZbunSkmqabJlM7Mzq61G/view?usp=sharing

↑ This is an example of creating motion with Blend Shape.See? The combined movement that wasn’t working properly before is now being handled automatically!

It’s seriously convenient.Like I mentioned in the last article: with normal parameters, the more keys and parameter types you add, the more exponentially the amount of manual adjustment grows.

Here’s a simple calculation:

2 × 2 = 4

3 × 3 = 9

4 × 3 = 12

3 × 3 × 3 = 27

3 × 3 × 3 × 3 = 81

Scary, right?!

But with Blend Shape, no matter how many keys or parameter types you add, everything is calculated automatically—so your workload is crushed★down.

↑ You could pile on this much complexity and still be totally fine.

At this point, you might be thinking:“Wait, then why not just make everything with Blend Shapes?”

Unfortunately, it’s not that simple.Blend Shape can only do automatic calculations.

So, you cannot make movements that differ drastically from the auto-calculated result.

Here’s an example: I tried making a blinking motion with Blend Shape.

https://drive.google.com/file/d/1oMb0lCbYK51sMsHNQJ97RaBubRlnyXjR/view?usp=sharing

See how the smiling-eye blink ends up looking completely wrong? lol

What happened is that the deformation from “normal closed eyes → smiling closed eyes”got automatically reflected onto “normal open eyes → smiling open eyes.”

Not what we wanted at all.

That’s why Blend Shape isn’t suitable for things like blinks or face angles, where you need delicate, key-by-key control.

Instead, it shines in situations like jiggle deformations used in physics, or small expression variations such as “tired eyes” or “duck lips.”

https://drive.google.com/file/d/1muj6oZzeUj-sDOTbyn55FXaC9RAMhKLX/view?usp=sharing

↑ Example: hair jiggle. Thanks to auto-calculation, the movement is super smooth!

https://drive.google.com/file/d/1YlC7HjKPjGhQw4qByZ0vhDnS9luDb5cO/view?usp=sharing

↑ Example: duck lips and tired eyes. Since eyes and mouths usually already use two base parameters, adding small extra movements via Blend Shape saves a lot of time.

So, keep these pros and cons in mind, and make good use of this ultra-handy, god-tier feature: Blend Shape.※ Starting from the next section, we’ll be using it a lot!

------------------------------------------------------------------------------------------------------------

[Optional] Creating highlight “flower” sway

Finally, we’re getting into deformation! Sorry the introduction always gets long whenever a new feature shows up, lol.

If you’ve never touched Live2D’s Physics function, this might not click right away.But for movements intended for physics—like in this case, the “highlight jiggle”—you still first rig them by setting keys on parameters or Blend Shapes!

https://drive.google.com/file/d/1JxbfYibKxRyqwgGiANch_E5-TUdiES5X/view?usp=sharing

↑ Like this! When you move it manually, it looks way too exaggerated and unnatural,but once you later automate the motion with the physics function, it suddenly looks super cute. Strange, right?

I created two parameters for the highlight:

★→ Iris Highlight 1 and ★→ Iris Highlight 2

First, select the Highlight Flower → art mesh, and set 3 keys on ★→ Iris Highlight 1.

If you’re using Blend Shapes, the way you set keys is the same as with normal parameters! Click the green circle mark at the top left.

(Totally trivial side note: for Blend Shapes, 2 points are fine as well.The result is the same whether it’s 2 or 3, so don’t worry either way.)

When you set a key on a Blend Shape, the key appears as a square instead of a circle.If it shows up as a circle, that means the parameter isn’t set to Blend Shape. In that case, delete the key, then right-click the parameter → Edit Parameter → and make sure to check Blend Shape!

(If you’ve already set a key on a parameter, you won’t be able to switch it to Blend Shape until you delete it. Conversely, once you’ve set a Blend Shape key, you can’t uncheck Blend Shape without deleting it first.In the screenshot above, the check is locked because I’ve already made the deformation with Blend Shape keys.)

Once you’ve successfully set square keys, adjust ★→Iris Highlight 1 so that when the value is 1, the highlight gets larger, and when it’s -1, it gets smaller.Hold Shift+Alt so it scales from the center without changing the aspect ratio. (Shortcut recap!)

https://drive.google.com/file/d/1d2XSDwrwrlSraZLBDKd9CaZsQuKh0xcY/view?usp=sharing

How much you scale is totally up to you! The more dramatic the change, the more dynamic the motion will feel.

However, when enlarging, make sure it doesn’t go too far outside the Deformer.

I explained a bit about deformer overflow in the previous article 【Essential】Eye Deformation

https://www.patreon.com/posts/135146927

If the mesh goes too far outside its deformer, it can cause unexpected behavior.A little overflow is fine, but having it stick way out unintentionally is best avoided!

The same logic applies to this highlight, so it’s better not to enlarge it in a way that makes it spill way out of the deformer like this:

Once you’ve finished the deformation for ★→ Iris Highlight 1, move on to rigging the deformation for ★→ Iris Highlight 2.

This time, we’ll make a motion that rotates left and right.You can rotate by dragging near the four corners of the red frame around the art mesh (the cursor will change shape).

https://drive.google.com/file/d/1laWN4CCELKGhfqDJlrRcvVM2_puYqY74/view?usp=sharing

When rotating, hold Shift while dragging to snap the rotation in 45° increments.

https://drive.google.com/file/d/1YhXE_9Va7VAl6WF5qJAotCtTUFtss3s5/view?usp=sharing

This time we want it to rotate exactly 45° to each side.So, while holding Shift, move it once in each direction!

https://drive.google.com/file/d/1mQmAfseaJLi9VU0BqDcnepywBbReq3Tb/view?usp=sharing

★→Iris Highlight 2 doesn’t end here—we’ll be adding one more adjustment.But since this is getting long, we’ll stop for now.Next time, we’ll continue with the correction process for ★→Iris Highlight 2.Stay tuned! 😆

--------------------------------------------------------------------------------------------------

Bonus: How to check which parameters are linked to an object

This bonus section was inspired by a comment from Takaki-san—thank you as always for your feedback! (´;ω;｀)(´;ω;｀)

Now that Blend Shapes are a thing, it’s no longer unusual for a single object (a general term covering ArtMeshes, deformers, etc.) to be linked to a huge number of parameters.

And that leads to one big problem:

When you’ve got five, six, or more parameters tied to a single object, it’s easy to lose track and fall into total chaos.

But don’t worry!

https://drive.google.com/file/d/1Z-93ngNMh4qI7D3UqIkuuX4v6qTLyPFC/view?usp=sharing

There’s a function that shows only the parameters currently linked to the object!!!

It’s super simple—just click here (the red circle).Clicking toggles it on and off.

Now, to be precise, the feature I introduced isn’t quite the same as the one Takaki-san asked about.His question was about filtering from parameter keys to specific ArtMeshes, whereas this feature works the other way around—from an object to its linked parameters.

So the functionality is similar, but not exactly the same.

Still, this method makes reverse lookup from an object to its parameters really simple! ✨

If you have more questions, feel free to ask anytime 🥰See you next time!!