Better Mouth Posing by the addition of more controls: Proposal.

Hey guys! I’ve decided to do a little write about this idea I had that now seems to be accepted. I hope this could give a better light on what I want to do and maybe inspire other model builders to add it to their models as well. So let’s begin:

Problem

Mouth posing has been both a hit or miss in all models built by everyone. This is because there is not enough control for the user to work with.

Strategy

I don’t share the idea of everything should be posed via flexes. I’m more of the idea you only use flexes if don’t have bones, but if you have flexes and bones, combine them. This makes it another issue, but we will tackle it later.

Adding more bones does not necessarily means “add more weights.” Where we are currently sitting, I think it’s pretty safe to say we can’t have the luxury to weight in more bones.

After thinking for a while about it, I thought about an idea that could give users more control without many compromises.

Here are my findings.

Current Setup

Regularly, most models come with a regular bone hierarchy:

• Head
   
  • Upper Lips
     
  • Mouth Corners
     
  • Jaw
     
    • Lower Lips
       

While this is enough to work, I think it can be better. The issue I can see from this current setup, is that you have some control, but having more control is not bad.

This made me think how can I get more control with this current setup without the need of weighting in more bones and potentially disrupt the face rig?

And then I saw it.

Introducing “The Advanced Mouth Control” system.

Quick note: yes, I love pretentious names.

Objective

Provide better mouth posing without disrupting the current rig.

First inclusion in some models by accident

Interestingly enough, accidentally, I added in some models (the latest one thing, I believe, Ada Wong) the basic idea, but instead of going for the mouth, I went for the eyelashes.

Some models have their eyelid bones positioned in bad places. Normally, when you rotate Eyelid bones, the result should be either an eye more open or a blink. In some models, none of that happens, as the eyelid only moves the fold around.

To fix this, I added a new bone that would control the proper eyelid bones (Eyelid Root) and when the Root were to be rotated, now it will give me the desired result: an eye more open or a blink.

By adding that bones, I inadvertently made eyelid posing not even useful for me to create flexes, but it was better for the user to pose.

It was thanks to the Eye Roots that I was able to come with this idea to make posing better.

Description of the system.

Stated above is a clue of how does the system work. The system works by the use of roots for every major set. Here’s the list of the roots that are involved here:

• Mouth Root
   
• Lip Corners Root
   
• Lip Upper Root
   
• Lip Lower Root
   

With this information, this is how every root should work.

Mouth Root

Normally, every main face bone is parented to either a “Face” bone or straight to the Head Bone. That is the case for the jaw, the upper lips and the corners, so if the head bone moves, the face bones follow along.

Instead of that, every Mouth bone is going to be parented to another bone: the Mouth Root, which in turn, is going to get parented to the Face/Head Bone.

That way, if the Head bone is moved, it will follow along as it always does, but now, by having a Mouth Root, you get control over the whole mouth, thus giving you more control for pose adjustments.

Lip Corners Root.

This is Parented to the Mouth Root Bone. I first saw bones like this in Dragon Ball Xenoverse models. I think the XNALara community renames them as Smile bones.

By having a Corner Root bone, you get to pose both corners in the proper position and you still have access to each corner bone for even more adjustments.

I recommend Rotating this bone and use Translations the less as possible.

Lips Root.

The Upper Root is parented to the Mouth Root Bone while the Lower Root is parented to the Jaw. By having these roots, you can adjust the upper and lower lip independently, and once you have that position, you can use the regular mouth bones to make pose adjustments.

As you can see, the only bone that doesn’t have a Root Bone, is the Jaw, however, that is not the case, because the Jaw should not have to be adjusted unless is broken. This is why it’s parented to the Mouth Root.

In a Hierarchy Look, the system looks like this:

• Head/Face
   
  • Mouth Root
     
    • Jaw
       
      • Lower Lip Root
         
        • Lower Lip Bones
           
    • Mouth Corners Root
       
      • Mouth Corner Bones
         
    • Upper Lip Root
       
      • Upper Lip bones

Issues and Limitations

As every solution, there is also a few limitations. And this one is no exception. Even I’m pretty sure the system works, there’s one huge caveat for this setup: it is intended for bone posing instead of flex posing. Yes, one can argue you can use SFM’s native presets to make things work, but I’m not about that “Forcing people into doing stuff certain way” life.

The other limitation, is the one that came on my dreams: there’s a big chance posing is going to be more difficult in very specific scenarios.

The scenario that happen in my dreams, was because I made the manual bone adjustment first and then do the flex adjustment second (or as I call it, “Bone First Flex Second.”)

Doing this not only is incorrect, but is also a really bad practice.

The reason is pretty simple: if you use a flex, the bones do not change positions, which means, if you use Jaw Drop and were to select the Lower Lip bones, you are going to see the highlighted bones floating while the Jaw is all the way down.

So the solution is Learning how to use this combination, and it’s pretty simple:

Step 1: Make use of the flexes for the general pose.

Step 2: Once the general pose is done, make adjustments using the bone.

Step 3: Done.

Nothing else. In Math, the order of the factors doesn’t change the product, in this case it really does. Flexes are, to put it in a simple way, status changes into a model. These changes are only made on the mesh though, so when you try to move the bones, you can, but it’s going to give you different results because the state of the model has been changed.

Think of it like a car. If you are in Neutral speed and you kick the gas, nothing will happen. If you are on 1 and kick the gas with the exact same force, not only stuff will happen, but chances are you are going to call your Insurance Company. Please drive safely.

There’s more on this topic though.

In my dreams, one of the issues I ran and the one that made me say “I should have seen this coming from a mile away” was the Mouth Corner Root.

So I don’t want to repeat myself, basically this is another Bone First Flex Second issue.

This is why, in my dream, I came out with a solution for the corners: Two Stage Flexes.

Some people are not aware of this… actually, a lot are not, but here’s a fact that every people aspiring to both get better at posing or become Model Builders should know:

The Half State of a Flex does not equal to the actual half state of the pose.

I can only explain this easier with pictures.

The difference not only is visible in the front. The wireframes won’t lie. If it’s visible in the front, when you put look at them through another angle, the difference is really notorious.

THIS IS WHY YOU SHOULD NEVER RELY ON USING ONLY FLEXES FOR YOUR POSES.

So, with that in mind, this will make more sense. In the case people want to use this same setup, and the Rotating Bone doesn’t work as intended, I plan to make 2 Corner Rotation Stages:

At Stage 0: it’s the where they are. No changes.

At Stage 1: this flex is made only using half of the rotation.

At Stage 2: this flex is made using the full rotation.

As I’m writing this right now, and I’m thinking about how this may seem a little difficult to make. For certain, the corner lips should never be all the way to the bottom, but they need to be able to rotate nonetheless. Right now I’m thinking about the current setup instead:

Jaw Drop Flex.

Lips Corner Rotate Flex (Name still wip)

Lips Corner Rotate Fix (This won’t do any changes by itself, is a Trigger Flex)

Then, make a Corrective Shape by using Jaw Drop and both Lip Rotates flexes. The reason why Lips Corner Rotate Fix is used as a trigger instead of a base Flex, is because I just the idea to use it with the model features of Corrective Shapes. I won’t get too much into this topic because this may get way longer.

Wow I’m pretty surprised how the whole Corrective Shape thing just came out of nowhere lol

Key Limitation

Now, after this whole thing, there’s one key limitation for this setup: it is not available for every model. This feature is only available on models with face rig. This means most, if not all MMD models and FACS only flexes are not going to be able to get this… not that it matters for the FACS only models since they are banned.

Now, with all of that say, here’s a bunch of screenshots of experiments :D

Experiments

Model used: Tifa.

Objective: Create poses only with flexes, then make them better with the setup, using a combination of both flexes and bones.

Modifications made to Tifa: Implemented the Advanced Mouth Control. Added Corner Rotate Flex and Corrective Shape.

A thing to keep in mind, is that this model uses its original rig. The rig is not perfect, hence why some bones manipulation may look a bit off.

Pose 1: Smile with slight mouth Open.

Posed using flexes exclusively.

Mod - Posed using the jaw bone and the Corner Root bone, while using the Smile and some Lip flexes for adjustment.

Personal Conclusion: The use of Corner Root while also keeping control of the corner bones themselves can help greatly with mouth posing. It might not be as clear, but you can see the differences above the mouth corners.

Pose 2: Mouth open in a surprise.

Posed using flexes and the mouth corner bones to adjust the mouth (and failed.)

Posed using the jaw flex and the Corner Rotation flex, while using the Corner Root for adjustments.

Personal Conclusion: While it can be problematic to use them at once, having a good balance between the Corner Rotation Flex and the Corner Root bones can also improve the posing.

Pose 3: :eyes:

Posed using flexes exclusively.

Posing using a combination of flexes, Corner Roots and Corner Rotation flex.

Personal Conclusion: This particular one in this particular model seem to be debatable. I personally believe the Modded version looks better, while the regular version seems a little jaggy. The issue in here is the original rig though.

Bonus Screenshot: Mouth Manipulation

Whenever you wanted to manipulate the mouth, all you could do is move the lips and the jaw, and that was it. If you were to rotate the neck or head bone, this is all you could do.

Neck Bone rotated. Jaw Bone rotated.

With the Controls I propose, you can have control over the mouth, so if you were to rotate the neck or head bone, you can also rotate the Mouth, this way, you can go from micro adjustments in your pose, all the way through to fully stylized posing.

Neck Bone rotated. Mouth Root Bone rotated. Jaw Bone rotated.

Keep in mind this also can be implemented (and will be implemented regardless) to problematic Eyelids.

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Well, that’s everything I have to show. Now, this is where you guys decide if these changes are worth or not.

Please, I beg you, please, write a comment if you agree or disagree with these changes. I want people to voice their opinions, so please, help me by writing a comment.