1 | P a g e

PMD/X Tutorial

…………………………………………….

Physics and Joints

First Published: 07/07/12

Updated On: 12/08/12

…………………………………………….

12/08/12 – Added a section on PMX Editor’s commands window. This should

help you to find the commands needed to make physics and joints.

14/07/12 - Updated Contents layout, fixed Title and added a section on Static

and Physical Physics.

2 | P a g e

Contents MAIN SECTION

1. Introduction …………………………………………………………… Page 3

As the title says, it’s an introduction to the tutorial.

2. Let’s make Physics and Joints! ................................... Pages 4-5 This section shows you how to make physics and joints.

3. The Idea of Joints …………………………………………………… Pages 6-9 Explains what the idea of joints are and what they are supposed to do.

4. Let’s play in Groups! ……………………………………………… Pages 10-12 Shows the importance of Groups when making physics.

5. The Final Test ……………………………………………………….. Page 13 Shows the final outcome of adding physics and joints.

EXTRA SECTION

6. What happens if you don’t use Joints? ………………….. Page 14-15 Shows what happens when you just make physics and no joints. It also highlights

what happens when you do not connect joints.

7. Resizing/Move/Rotate Physics ………………………………. Page 15-16 Explains how to resize

8. Static Vs. Physical …………………………………………………... Page 17-21 Explains the difference between static and physic physics. Highlights why dropped

physics may still occur.

9. PMX Editor Controls…………………………………………………Page 22-23 Shows the commands for adding physics and joints with PMX Editor.

#. Conclusion ………………………………………………………………. Page 24

3 | P a g e

1 – Introduction.................................................................... Today I am going to try and teach you about making physical physics. In other words physics that are

part of a dress/skirt/hair or whatever else you need to make move ‘freely’ or ‘physically move’ like

they do in real life.

We are going to use Miku (because I’m original). This is what she usually looks like with her physics

and joints;

But Meiko’s stolen her hair physics and joints (she’s jealous of Miku’s hair). So now they don’t work

at all with the physical operation.

So we’re going to have to fix that now aren’t we?

4 | P a g e

2 - Let’s Make Physics and Joints!..........................................

Firstly, let’s make some Physics and Joints!

Make sure that only the “B” is selected at the top of the window where you can see your model.

Then select the bone that you want to add a physic and joint to. (Only do one bone for now).

We then go to both of the following;

Edit > Bone (B) > Create Phys Found.

Creates a Physical Physic (Can be later changed to Static)

Edit > Bone (B) > Create Joint

Creates a joint to hold the physic in place.

5 | P a g e

Click them to add them to the model as show below;

Congratulations! You just made your first joint and physic! However we aren’t done yet. We still

have something very important to do with the joint you just made.

So we have to go to the Joint section on the other window;

It looks scary and a bit nasty, but It’s not really that bad;

6 | P a g e

3 - The Idea of Joints………………………………………………………… This may get confusing, but I can assure you that it’s actually very simple once you understand the

basic principle of adding joints and physics.

Okay. The idea of Joints with AttachA and AttachB is that you are telling Joint 1 that “Physic 1” (Hair

Physic 1) is attached to the Head Physic (Attach A) and also to the Hair Physic (Hair Physic 1) that you

just made (Attach B).

It’s basically like a jigsaw puzzle, you have to put them in the right place; else they won’t fit.

However, in order to put the piece there you have to tell it to go there.

Joints are the same. You are telling the Joint that Hair Physic One is attached to the head physic. This

tells it where the physic is in relation to the model/part.

So it turns out like this;

Joint 1 -> Head Physic -> Hair Physic 1

However, if you make a second Hair Physic, you don’t tell its joint that it’s attached to the head

bone. Instead you tell it that Hair Physic 1 is attached to Hair Physic 2.

Joint 2 -> Hair Physic 1 -> Hair Physic 2.

This means that your First Hair Physic is a part of Hair Physic 2.

7 | P a g e

I will show you what I mean by this. Do the same thing as before to create Joints and physics for

Bones 2 and 3. Look below.

Can you see the pattern yet?

Joint 1 has been told that its friend from down the street (Head Physic) has made friends with Hair

Physic 1.

Joint 2 has just been told that its neighbour Hair Physic 1 is related to its own Hair Physic 2.

However, at the moment, Poor Joint 3 doesn’t know that it can make friends with Hair Physic 2 with

its own Hair Physic 3 despite the fact that they’re both distantly related by blood. Should we fix

that?

8 | P a g e

This is what you should have so far. Do you see how it’s shaping out now..?

Let’s continue our work and make the rest of the physics and joints.

Well. Look at that! We’ve just completed adding in all our physics and telling the joints what physics

go where and who attaches to who!

Now let’s save her and open her in MMD and let’s switch display bodies on…..turn her physics on…..

and-----

9 | P a g e

WHAT THE EFFFF?! D: It eats people!

Don’t worry. There’s a way to fix this. I just wanted to allow you to see what happens when you

don’t change a physics groups. Let’s go onwards~!

10 | P a g e

4 - Let’s play in Groups! ……………………………………………………...

Re-Open her in PMDeditor and go to the PH tab~ Locate her hair physics.

You see the problem here is that we didn’t set up which physics can go through each other and

which cannot.

In this case, the hair physics that we made currently conflict with each other because they aren’t

allow to pass through each other to become a freely moving physic.

We can however fix this with groups! You see where it says Group with a number in a drop down

box and then those little tick boxes under it with Collide next to it? We use those.

I’m going to choose Group 16, because its unlikely that anything else on the model – like legs and

arms will go through her hair instead of repelling it. Make sure you have the following blue swirl (it’s

a blue physic really) on so you can see the change in the change in physic colour.

11 | P a g e

Look at the difference now in PMDeditor. However we are not done yet. See the Collide box?

We have to now check Group 16 there as well. This tells the Hair Physic’s that they can go through

each other.

Should we test it out..? Let’s open MMD and turn the physical operation on.

See! It now works~ However, the battle isn’t over yet. Look at her Left Pigtail. Its very lonely… You

should cheer it up by adding Physics and Joints in the same way!

12 | P a g e

Make the joints and physics back in PMDeditor using the same method above, but make sure that

you are attaching the correct physics to each other and that their groups are correct, as shown in the

example below;

Remember that the first Hair Physic will attach to the head physic via the joint, with the rest of the

physics following them with their own joints.

13 | P a g e

5 - The Final Test……………………………………………………………..

Then it can be all happy again. Like this;

There isn’t much more to say on this note.

You may be interested in looking at the resizing/moving and rotating tips in the extras section in

order to make sure that the physics repel each other – like on the original Animasa Miku model.

All that’s left to do now is just sort out the physics settings, from experience the higher the number

is, the more ‘weight’ it has so it won’t move around as much, the lower the number the less weight

it has – and the more it flies around. Think panty shots.

It’s probably easier to explain if you take a look at other people’s physics and see how much weight

there is on the physic in order for you to decide what your physics settings should be.

Physic settings can be found here in the PH tab;

However, I currently do not know much about them to describe to you what each one does, so you

will have to experiment through trial and error.

14 | P a g e

EXTRA SECTION……………………………………………….. This is just a little add on section to help you understand some joint and physic related problems.

Along with some tips and tricks on resizing physics.

6 - What happens if you don’t use Joints?...........................

Many users experience these kind of problem’s when they do not use joints to hold their physics in

place.

No Joints (Miku’s skirt) Missing Joint (Miku’s Second Tie Joint)

As you can see, this is what happens when there are joints missing. This can also happen when you

have not connected the right joints and physics together. Except from my experience they like falling

THROUGH the coordinate axis rather than resting on it (falling to the floor).

This is why it might be best to put English names after the Japanese on the bones so that when you

make the joints and physics they will also have the English after the Japanese, making it easier for

you to tell which is which. You can always delete the English afterwards.

JP: (Japanese) 1 [Front. Skirt 1 Left]

English: Front L. Skirt 1

On a side note, while the first hair physic attaches to the head physic, skirt physics attach to the

lower body physic.

The first Boob physics will attach to the upper body bone – depending on how many of these bones

are on the model will determine where it’s connected to. If you have three upper body bones, they

connect to the third one; look for the one that is connected to the neck bone.

Any physics in sleeves will probably attach to the second arm bone – the one before the wrist.

15 | P a g e

I think that this concludes this small section. The bottom line is to make sure you know where the

physics should be connected to via joints. Just test it out and experiment.

7 - Resizing/Move/Rotate Physics…………………………………….

Another thing to add is that you can also move physics, resize them to an extent and rotate them

into place.

In order to resize, move and rotate physics you can use the following. The Control Window [C], or

the options within the Physics tab [PH].

Resizing Physics

For example with a new physic this is what it looks like when you change the

Si/Pos settings to 2. It becomes a square. You can also make it larger by using the Control Window [C]’s box at

the end at the top; which will resize the entire physic – like it does

with model parts e.g. hair, clothes ect. You can ONLY use that button to

enlarge physics if you use the Control Window, if you want to change the shape you HAVE to use the Si/Pos

settings in the PH tab; else it won’t work.

16 | P a g e

Rotating Physics

Like with resizing physics, you can rotate them in the same way, except that it is easier to do so with

the Control Window [C] rather than using the Si/Pos section. You can also click the physic to bring up

the Arrow Control thing (shown below) which is actually easier to use. All the options on the Control

Window [C] work with Rotation.

It is important to note that SOME of the controls may change when you rotate a physic. For example the resizing options may change slightly because the physic has been rotated. You’ll see what I mean when you try it out, as it is hard to

make an example for every different change.

Moving Physics

You can just move physics in the same way that you do with model parts with either the Control

Window [C] or the Arrow Control (pictured previously). Just make sure that the joints are moved with it else you’ll probably end up with

weird results.

I think that this is all I can say for this section, as there isn’t much more to add on the subject. As I

stated before, it is probably best to just experiment with different sizes of physics and the physics

settings. It might also be an idea to have a look and see how other model’s physics are – such as

Animasa Miku’s Hair Physics.

17 | P a g e

8 - Static Vs. Physic………………………………………………………………

A few days ago when I was adding physics, bones, joints and rigging to the hair piece pictured below,

I suddenly realised that I had forgotten one important thing that I forgot to tell you; when to use

Static Physics and when not to use them - or rather when not to use the physics automatically given

to you when you first make them with the “Edit > Bone (B) > Create Phys Found” command.

When you use a Static Head Bone. (Greenish) When you use a Physical Head Bone. (Orange)

But what are Static Physics? And how are they different from physical physics? The Two pictures

above show you what to avoid, but why do you avoid them?

This section attempts to explain Static and Physical joints along with showing you how to activate

them and deactivate them.

Static Physics

Static physics are physics which do not move, but still give the bones physics in order to repeal

certain physics or hold them in place – like with hair physics. Examples of such physics can be found

in the arms and body of the model.

The legs are also static physics, if they appear to look a different colour than the arms and body, this

is down to the Group that they are in, but if you look at the outline of the physics and the physics

side colours you’ll notice that they are remarkably different creatures all together.

18 | P a g e

For example, if you look at the picture of ETO Haku’s body physics pictured below you will notice

that they are Static Physics but they have different groups all together.

A models static physics shown above. ETO Haku. The type of physic is shown on the Left and

its Group is shown on the right.

It is also important to note that Static Physics are not affected by the Physical Operation control and

are instead used to repeal other physics which also depends on their Group, as metioned previously.

We covered groups before, and it is the same sort of Groups that you used when you made your first hair physics and were trying to stop them from conflicting with each other. It is important that you make sure that you know what a phyics group is, else you may run into conflicting problems and/or things like hair physics going through the models body.

This is why models repeal their hair when it comes towards their body. Alternativly if the model does

not have an upper body physic and they have long hair physics, the hair physics will go through the

body. The same also applies if their arms do not repeal the hair physics.

You may have also noticed that with many of the 3DCG hair physics that a lot of them seem useless

due to the fact that they do not have ‘working’ physics. In actual fact what you are seeing are static

phyics which can be changed to physic physics which will then be affected by Physical Operation in

MMD7.39. This means that you do not have to ‘redo’ the entire models physics, you can just change

their properties to being Static or Physical.

19 | P a g e

These types of physics still need to be connected to a Physical physic via joints in the same

manner/order. Just because you changed them from Physical to Static does not change anything

about the importance of joints!

Physical Physics

Physical Physics are physics that will be repelled by Static Physics. Of course we also all know that

they also make things like skirts and hair more realistic when a model moves when the Physical

Operation option is on in MMD7.39.

As covered previously you need joints to hold these physics in place along side the static physics.

Without joints the physics will fall to the ground dragging the bones and parts down with them.

I think that that’s all I can say on Physical joints in this section, due to the fact that the first half

focused on their properties, settings and groups more than the Static Physics.

It is important to know that you should never make any part of the body – unless it’s the models

boobs, have physical physics because without joints this will happen. Just don’t do it.

When to use them

If you are using Static Physics on hair such as 3DCG, it may be a good idea to make sure that the top

hair physics which are connected to the head physic are static physics. Why?

20 | P a g e

From experience if you do not do this, then the physics will fold in on themseleves. This can probably

be solved if you place enough head physics near the hair, but there is always a risk that they will

suffer from confliction problems and/or twitching/updraft hair. Small twitching does not matter,

although it is slightly annoying.

However, as said in several previous sections of this tutorial, it may be best if you experiment with

them and see what works and what doesn’t. Remember, although this is a tutorial on Physics and

Joints, this is how I use them, you do not have to use them in the same way.

Only use Physical Physics on parts which you want the Physic Operation to affect and never use

them on the body unless its for the models boobs.

Changing Physic Types

All you need to do to change the type of Physics a Physic is is choose one of the following options

above and it’ll change the type of physic that it is. That’s all there is to it. I believe that there is no

real need to explain in detail how to change them, as there isn’t much to it.

Just experiment with it as I’ve said many times before, you will probably find something that works

for you without me breathing down your neck.

21 | P a g e

Just remember if you want a physic to move physically (hair/skirt) it needs to be physical.

If you want the hair to not go through the body then make sure that the body’s physic is Static and

that whatever group the hair physic is not allowed to enter the body physic. So if the Hair Physic’s

Group is Group 7 then make sure that the Body’s Static Physic does not have Group 7 checked in its

group section – else it is allowing the hair through it.

Unfortunatly at this moment in time I cannot remember what the Align Bone does. That is why I am

emphazising that you should experiement with your physics.

22 | P a g e

9- PMX Editor Commands ………………………………………………

This section is for those who use PMXeditor and are unsure where the commands are for making

physics and joints. Once you know where they are, the process should be the same as above; make

the physic and joint by selecting the bone, then telling the joint where the physic should be held up

and finally what group the physic is apart of. –phew-

Here they are. They’ve been staring you in the face this entire time. The only difference is that its

easier to tell the difference between making a static and physical physic.

The first option is “Create a Static Physic”. These are arm physics and so on.

Next is “Create a Physical Physic”, which includes stuff like hair and skirts.

However, this time we also have two joint commands. Just to confuse the hell out of you when you

try and make joints. I personally think that the first command gives you a ‘normal’ joint, while the

other option probably gives you a ‘special joint’ of some kind. But I’m not sure.

I believe that the tabs are more or less in the same order that they were before. So there shouldn’t

be any problems trying to find a specific tab. You should be able to tell what each tab is by looking at

each one seperately; although I have included screenshots of them below.

Sorry that I am not much help with PMX, but now that you know where the commands are, you

should be fine following this tutorial. You just don’t have to worry about choosing whether or not a

physic is static or physical anymore because PMX does it for you.

23 | P a g e

Physics Window

I do not think that much has changed in this window. It is mostly the same, its just in Japanese.

Joints Window

The only real thing that has changed in this window, is that the positioning commands have become

larger and now there is something that I’ve dubbed “Joint Type” because it appears to hold different

options for joints such as ones for facials and IK bones if I remember correctly. Everything is mostly

in the same place as it was before. So there is no need to worry.

I hope that this section helps you and hopefully soon I’ll be able to increase this section.

24 | P a g e

# - Conclusion…………………………………………………………………..

That concludes the tutorial on Physics and Joints as I think I have covered everything that I wanted

to cover in this tutorial.

If you have any questions then please feel free to ask if you are unsure about anything and I will try

to help you.

This tutorial is avaliable for download on the side under Add to Faves and I will also be including

Miku’s files for those who want to have a closer look at what I have done. I have even included all

the pictures as well. The download for this will be in the description below.

I hope that this has helped you to understand physics and joints a little bit more.

Also, while I realise that you can do this in MMD7.39, those tutorials do not help me at all when I

open MMD, so I made a tutorial explaining the process in PMDeditor instead.

I updated this tutorial on the 14th July 2012 with more information on static physics and physical

physics, which I also hope will help you understand some common problems that sometimes occur

due to not setting up physics correctly.

I also made the layout of the document more appealing and fixed up the contents and some

mistakes.

Additionally on the 12th August 2012, I also adjusted this tutorial to include some information

regarding the command windows of PMX editor. We hope that in the future we can add more about

PMXeditor to this tutorial – or make another separate tutorial for PMX.

Also, thank you to the people who have currently downloaded this tutorial and have used it. I am

happy to know that it has been useful to all of you in some way.

Thank you for reading.

- yesbutterfly

……………….……………….……………….……………….……………….……………….……………….……………….……………….

Credits go to 3DCG, ETO, MMDFakewings18, HousekineMinto and Amiamy111, whose parts that I

used in this tutorial. And also to Animasa for their default model which is also used for most of this

tutorial. Tda’s Append Miku model is also shown in this tutorial as well.