Kawaii Physics - Simple fake physics to sway bones more easily and more cutely

Hi everyone!

I publish this plug-in developed for someone are struggling to adjust PhysicsAssets or AnimDynamics.

Kawaii Physics is a pseudo-physical plug-in created for Unreal Engine 4.
You can sway your hair, skirt, etc more easily and in a Kawaii way :slight_smile:

Show case:


  • Controls each bone physically while respecting the pre-physics shape
  • All you need to do is add Kawaii Node to AnimGraph and adjust few parameters.
  • Sway the specified bone and the bone below it according to the movement of the character.
  • Much easier to set up than AnimDynamics
  • You can use sphere, capsule, plane collision
  • You can adjust the position, orientation and size of each collision in the animation editor viewport
  • Since the bone length is maintained, even if the calculation is broken, the bone does not expand or contract.
  • Uses a simple algorithm without using PhysX, so the cost is lower compared to the engine’s standard physical system.




  • Content/KawaiiPhysicsSample/KawaiiPhysicsSample

My simple fake physics KawaiiPhysics sample level - YouTube


  • MIT


Hashtag of SNS:

  • #KawaiiPhysics

I made this as hobby. So I’m glad if you don’t expect great support.
Finally, I hope this plugin will help you :slight_smile:


Updated to v1.01

  • Fixed a issue Collision’s OffsetLocation doesn’t use bone rotation
  • Default settings of all debug display to ON
  • The type of collision currently selected is also displayed on the lower left of the preview screen.

Amazing! Thank you.

Hey @pafuhana1213, thanks for the plugin!

Updated to v1.1

  • Changed Wind property to take into account WindDirectionalSource. So, the affinity with NvCloth and SpeedTree should have improved :slight_smile:

Does the plug-in support ue4.23?

This is pretty cool.

Any chance of 4.19 support?

Updated to v1.1.1

  • Fixed wrong calculation of Bone.LengthFromRoot

I uploaded a compressed zip file with plugins from 4.21 to 4.23. Since 4.23 should continue to update, github master is still 4.22.

For versions prior to 4.21, build should succeed if you change
GEngine->ConstraintLimitMaterialPrismatic->GetRenderProxy () to
GEngine->ConstraintLimitMaterialPrismatic->GetRenderProxy (false) in KawaiiPhysicsEditMode.cpp :slight_smile:

This looks great!
Although I have a question.
Does version 4.23 require rebuilding the engine or Is It a standalone plugin?

Its standalone plugin.

@pafuhana1213 are you thinking to put it in ue4 store so it gets updated for everyone automatically?

It is in the description “I made this as a hobby. So I’m glad if you don’t expect great support.”

So…dont expect that.

The file already seems to be set to that?

This is the error returned when trying to compile for 4.19.

Plugins\KawaiiPhysics\Source\KawaiiPhysicsEd\Private\AnimGraphNode_KawaiiPhysics.cpp(67): error C2664: 'NodeType *UAnimGraphNode_Base::GetActiveInstanceNode<FAnimNode_KawaiiPhysics>(UObject *) const': cannot convert argument 1 from 'UAnimInstance *' to 'UObject *'

Amazing plugin!
I’m trying to use it but I’m facing some problems. When I put the AnimGraph node on a bone, the piece of a mesh of a skirt bend to inside. Have you faced this kind of problem? If not, can you help me? I sent you a private message with my discord.

Updated to v1.2.0

To Selentic,
I’m sorry. However, I don’t want to support engine versions older than a year.
The part where the error has occurred is the debug display part, so it should be solved by commenting out or implementing it in FKawaiiPhysicsEditMode.

To LeoRocha_GameDev,
It’s impossible to support all models, and I can’t support each various models directly.(Time is not enough …)
Probably, the orientation of the end bone may be incorrect. The character implementation included in the sample should be helpful.

No biggie, I’m going to be upgrading sometime next year probably. I look forward to giving it a shot then. :slight_smile:

Updated to v1.2.1

  • Improved support for variable frame rates

Binary for UE4.21, 22, 23

Why not support it by official store plugin distribution?

Can this be compiled for UE 4.18 ?

Hi AngeIV,
I don’t have much time for support, so I don’t think about release in the store. I also want to work with everyone to make a better plugin

Hi Sabudum,
I can’t afford to support older engine versions. 4.18 support tips can be found in past posts