Braided Hair with Removable Ties – How to Keep Separate Assets Synced During Animation?

[nick.sammelsorium]

Hey folks

I’m experimenting with custom hair and accidentally discovered something
I’d like to implement on purpose:
I want the hair ties that hold the braids together to be removable,
so the character can wear her hair loose in certain scenes.

Currently, the braids and the ties are part of the same mesh, using two different materials.
Depending on how I paint the weight map, either the ties stay in place or fall off unnaturally during animation.

So I figured I might need to combine them into a single mesh with one material, and then create a second version of the hair without the ties for the open-hair look.

But here’s my actual question:

Is it possible to have the braids and hair ties as separate meshes/assets,
and still make the ties behave as if they are clamping the braids – even during animation?

If so, how should the weight painting for the ties be set up
so they follow the braids properly, without lagging behind or falling out of sync?

Any ideas or best practices are greatly appreciated!

[4u2ges]

It’s better be one mesh/one material. And loose/tied braids should be separate accessories.

Braids physics is not that different from any other hair physics.
The “secret”, is braid sections and ties geometry design. In order to keep the braid sections shape and prevent mesh folding at physics simulation time, a tube profile has to have a special geometry.

There is an old thread where I have a tut for making a special flex tube in Blender.
https://forum.reallusion.com/FindPost443792.aspx

Not everything in the video would apply to your case, but I assume you can follow base steps for making braid sections with that special profile.

I also made a quick “loose” braid with 3 sections and included a sample project

Braid.iProject

Loose Braid Physics

When you make ties for a braid (braid with ties has to be a different accessory I suppose), the tie cylinder must also have the same profile as braid sections and be part of the same mesh. In addition braid sections must be interlocked in a few places along the braid lengths (with some faces geometry) as well as with ties so that ties do not fall apart and swept away during physics simulation.

[4u2ges]

Here is another with interlocked braid sections and a tie.

Braid Locked Tie.ccAcc

Braid sections and tie are interlocked with a some random hidden faces

Interlocked Braid Physics

Extreme…

Braid Physics - Extreme

[garrypye]

As someone who has just started my 3D journey, this information has been very helpful. I am currently working on just my second 3D acotr build ever, and she just happens to have braids and hair ties. The timing was perfect. Thanks for sharing!

[Nirwana]

@4u2ges

Here is another with interlocked braid sections and a tie.

Awesome. (I wish I could get something like this to work in C4D—with the native hair, not as an Alembic import from iClone).

[AutoDidact]

@Nirwana

(I wish I could get something like this to work in C4D

You would have to rig the hair/cloth with a bone chain.
Maxon C4D has a “Bone Dynamics” system similar to what we have in Blender.

BLENDER NPR WITH EEVEE

Also you might get something similar with C4D’s rope dynamics

Dynamic Twisting Rope in C4D - Cinema 4D Tutorial (Free Project)

[Nirwana]

@AutoDidact

You would have to rig the hair/cloth with a bone chain.

Well, as I said, I’m talking about the C4D hair system which means no bones/joints, and no rope dynamics because “hair” is—AFAIK—not yet part of the unified physics system (in the last update, Maxon introduced native liquid simulation to C4D (pretty solid start, but not complete yet; there’s still stuff that X-Particles can do in terms of liquids that the native sim cannot). However, the hair system is still old and does not play nice with the newer stuff (although I have not really tried it for a while, but I think if they updated the hair system, that would definitely be in the release notes)).

The NPR look is not really my thing, neither to consume nor to create.

[AutoDidact]

Well, as I said, I’m talking about the C4D hair system which means no bones/joints, and no rope dynamics because “hair” is—AFAIK—not yet part of the unified physics system

Well that is a bit of a silly semantic, technical argument.

First, no CG character has actual “hair”
just some polygons or splines etc that are a visual representation of the organic strands of the protein “keratin” that exist on most mammals… AKA “Hair”

Of course some “Hair” simulation methods are better than others depending on the level of realism needed and the length of the “Hair”
But in the end,the lay person who watches
a CG animation does make not any such granular distinctions as long as it matches the level of realism or cartoony style as the rest of the animated film and has an engaging story.

Also I get it, you are not an animator or CG filmmaker but just a hobbyist tinkerer with disposable income .

How nice for you.

But my point was that a long dynamic “hair” pony tail animation is likely already possible in C4D for those actual C4D animators or CG filmmakers
who do not want to migrate & learn Blender, Houdini
or Maya

Maya xgenhair

And are not waiting for everything to be in the “unified dynamic system” before trying to achieve a VFX for a shot.

(in the last update, Maxon introduced native liquid simulation to C4D (pretty solid start, but not complete yet; there’s still stuff that X-Particles can do in terms of liquids that the native sim cannot).

Well each individual can decide for themselves if continuing to pay rent for XP is justified for those few things you say it can do “better” than the new fluid engine in C4D

My C4D R25 has the Realflow fluid dynamics plugin which is more than enough for any rare occasion where I feel like working in C4D for mograph etc.

The NPR look is not really my thing, neither to consume nor to create.

Well it is definitely my “thing” to both consume and create so you might remember to skip clicking on any sample videos I post on this forum going forward…just to be safe.

[Nirwana]

@AutoDidact

Well that is a bit of a silly semantic, technical argument.

Why? The problem I have is not braids, but keeping hair ties/ribbons, etc. dynamically in the C4D hair when these (the hair and the ties/ribbons) are different dynamic systems (the same problem the thread starter was having), i.e. they don’t interact well.
So the point that the current (ancient) C4D hair system is not part of the unified system is IMO fairly critical and not just semantics. If you know how to do that in C4D, please feel free to enlighten me.

I’m not sure whether what the Maya video shows can be done in C4D (I frankly haven’t tried putting “hair” on splines as guides yet). However, that clip does not feature any ties/ribbons holding the hair together; simply animating hair is not the issue. That said, there is definitely no way to show self-collision on splines in C4D that I’m aware of.

BTW: As you said, I “tinker” with things 3D in lieu of telling stories and if I decided to do a “narrative piece”, I think I’d post it on a new channel. My current one is not really meant for the CG lay person.

@AutoDidact

Well each individual can decide for themselves if continuing to pay rent for XP is justified for those few things you say it can do “better” than the new fluid engine in C4D

It is a little early to tell, since the C4D system has been out all of 14 days. Also, XP is an annual thing, and it’ll be a while before the next “rent” is due and any decision needs to be made (in fact, the next C4D update should drop before then, which may help with that).

[AutoDidact]

@Nirwana

Why? The problem I have is not braids, but keeping hair ties/ribbons, etc. dynamically in the C4D hair when these (the hair and the ties/ribbons) are different dynamic systems

Well it is a matter of context.

You appeared to be reacting to the dynamic animation of a long tied/braided pony tail by 4u2ges
when you said:

“Awesome. (I wish I could get something like this to work in C4D—with the native hair, not as an Alembic import from iClone).”

I suggested that this same animation could be possible in C4D with dynamic bones on a mesh based ponytail and you responded by that your hair animation must to be done with the hair simulation system and it is out of date etc…

If that is your personal philosophy
that is fine.
But it can be extremely limiting if you refuse to consider learning other methods ,that actually exist in your software, to create a similar animation
without ridiculous 12 hour simulation times such as this blender addon ,we recently discussed,
as an alternative to a “real” fluid simulation for a boat wake.

Generate Dynamic Oceans - Easy Wake Addon Tutorial

[Nirwana]

@AutoDidact

I suggested that this same animation could be possible in C4D with dynamic bones on a mesh based ponytail and you responded by that your hair animation must to be done with the hair simulation system and it is out of date etc…

I must have missed where you said something about mesh hair before. I thought you meant combining bones with C4D hair (not mesh based hair) and, AFAIK, that cannot be done in C4D. And the Maya video you linked did not show mesh hair either.

Also, if I wanted to use mesh hair, I could just export that from iClone, but that would give me more of an NPR look than I like. That is why I specifically said that I’d like to be able to achieve that with C4D hair (i.e. combining dynamic C4D hair with a tie or ribbon). For a tech demo, you know?

With regard to the Blender wake addon, I’m aware of no such thing for C4D, so I would have to brute force it (i.e. simulate it).

Also, I’m afraid, we’ve been hijacking somebody else’s thread, and therefore I’ll leave it at that.