Shin Megami Tensei V makes use the “Kawaii Physics” plugin for protagonist’s hair

An Epic Games Japan support engineer’s personal project.

Written by. Nick Mosier based on the original Japanese article (publication date: 2021-12-08 13:49 JST)

It has been revealed that Shin Megami Tensei V makes use of the “Kawaii Physics” Unreal Engine plugin, which was developed by Kazuya Okada, a support engineer at Epic Games Japan. Kawaii Physics is a pseudo-physical plugin for Unreal Engine 4 that is used for swaying things like hair and skirts in an easy and cute way. In Shin Megami Tensei V, the plugin is used to control the swaying of the protagonist’s hair.

Tweet Translation:
The recently released Shin Megami Tensei V makes use of the Kawaii Physics plugin I made! Thank you so much! (It’s apparently used to control the protagonist’s hair! I couldn’t believe it when I heard that lol)

Shin Megami Tensei V uses Unreal Engine 4, and from the ruins of Tokyo to the character models, is a step up visually compared to past titles in the series. The graphical improvements also extend to Nahobino’s long blue hair. As Nahobino runs, jumps, and performs other actions, those luscious blue locks beautifully sway along to match the movements. Players have likely taken notice considering how much of the game is spent looking at the character from behind.

Showing hair or a skirt swaying naturally is no simple feat. Many players have likely encountered unnatural looking hair and clothing movement in 3D games before, like hair that seems to not have weight or rigidity and just goes wild. But hair that’s too stuck in place also looks unnatural. Kawaii Physics is a plugin that handles that sway and movement in an easy and cute way.

The developer behind Kawaii Physics is a support engineer at Epic Games Japan named Kazuya Okada. In addition to helping companies with Unreal Engine 4, they can also often be seen taking the stage at seminars. Okada also interacts directly with the development community in their private time, and often spreads Unreal Engine 4 related information on social media. Plus, Okada is even making an action game called The Soldat with Twin Arms. Kawaii Physics is a personal project of theirs as well.

Kawaii Physics is said to be easier to set up than Unreal Engine 4’s standard “AnimDynamics” feature. In addition, it maintains the bone length, which helps prevent issues like unnatural expansion. It also supports collision detection and has a simple algorithm that is less taxing than the engine’s standard physics system.

This practical plugin was made available through the very unrestrictive MIT License. In other words, if game developers display the author and license, they are free to use Kawaii Physics.

On the Kawaii Physics GitHub page are side-by-side examples of Kawaii Physics compared to other methods. It’s notable how it doesn’t look unnatural and has a cute anime-style sway to it, similar to the protagonist of Shin Megami Tensei V, which uses the plugin.

Other examples of games that use Kawaii Physics include Scarlet Nexus, Blue Protocol, Final Fantasy VII: The First Soldier, and Trials of Mana. This personal project of Okada’s has made its way into a number of titles that are available on the market. Okada has also shared information on how to get the plugin working in Unreal Engine 5 (in Japanese).

Tweet Translation:
By the way, Kawaii Physics is a hobby project of mine and I’m not supporting it on a project-by-project basis. To all the programmers and artists who implement and finely tune it in their projects, I’m truly grateful.”