Yu Higuchi’s Anatomy: A Lesson on MMD Bones

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Yu Higuchi’s Anatomy – or – A Lesson on MMD Bones.

ANYTHING THAT MOVES, on a model, will have a corresponding bone attached to it. That’s why some models have weird things like hair bones and eye bones and other bizarre anatomy that you’ve never heard about in any of your Health and Anatomy classes.

Bones are made of marks and lines.  The marks indicate points of rotation and movement. The mark is where you select, rotate, and move the bone. Lines show you the direction you are going with that bone.

There are 4 basic types of bones (according to Yu Higuchi from his tutorial video):

1. Normal Bones (Rotate Only) have a blue circular mark surrounded a blue circle and blue lines.
2. Normal Bones (Rotate and Move) are indicated by blue square marks surrounded blue square and blue lines.
3. Normal Bones affected by an IK (Inverse Kinematics) Bone are noted with a blue circle and yellow lines.
4. or IK Bones (Inverse Kinematics) are distinguished by blue squares with yellow squares and lines. Sometimes, you’ll see a blue square with a yellow outline and blue lines.

The most common bones are 1 and 4. I included the other two because you might find these on older legacy models. Or occasionally, some model designer might do something exotic with their models.  Generally speaking, IK bones have square heads; Normal bones do not.

All bones rotate and move to some extent however, IK bones (attached to joints) allow you to manipulate an entire appendage all at once. Most often, IK bones are associated with the legs and feet. They are activated by double clicking on the mark. You’ll also notice that the Move button is not “greyed” out and you’ll see “IK” listed in the Bone field on the top left. This is not to say that an entire limb can’t be moved with a normal bone. You just have more options with IK bones.

All these bones can be moved by using the Rotate Axis Tool by clicking on the mark and clicking Rotate on the Bone Manipulation Menu.  Or, you can use the XYZ icon field in the lower right-hand corner of the model screen.

Personally, I find the Rotate Axis Tool the easiest to use. This in concert with a mouse and scroll wheel is the most efficient to use (Unless, you have a serious masochistic streak then use the XYZ icon field-to each their own).

Trust me, after 5 minutes of using only the XYZ icon field -You’ll get yourself a three button mouse!  Especially, when you start doing your own camera motion data, then, you will see the value of the mouse.

The last bone I want to mention isn’t really a bone?!? It is just a blue circle with a blue “x” inside of it.  That is just a rotation point. Try as you may, it won’t move up, down, nor side-to-side. It just rotates.

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This is just a basic primer on bones. MMD modelers are always pushing the envelope and creating new stuff.

I now hope you now have a better idea of what you are looking at, when you use MMD.

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– SEE BELOW for MORE MMD TUTORIALS…

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