Boob Simulator: Yes, It’s A Real Unreal Engine 4 Game

Using Nvidia’s FleX and the power of Epic Games’ Unreal Engine 4, one creator is taking the next step in virtual reality, interactive entertainment by introducing a game centered around the realism of boob physics. Yes, a game centered around the dynamic transfer of mammary mass through human simulated skin and the aftereffects of how said mass affects the bounce, jiggle, vibration and physical reactions of boobs. The Boob Simulator project is obviously NSFW. So viewer discretion is advised.

Designer Rathren is attempting to make the simulator include both the unrealistic and the uber-realistic elements of physical reactions attached to boobs. Think of it as the boob edition of BeamNG, which is a car physics simulator that aims to give gamers control of different vehicles under different weight classes and see how they physically react to crashes using soft-body physics deformation. You can check out a brief video of BeamNG below to get an idea of what it’s like.

In the case of Boob Simulator, Rathren explains…

“This projects goal is to simulate boobs with the most realistic physics and graphics possible. Doing so I use the newest technologies like Nvidia FleX [which] isn’t yet and might never even be officially released for UE4!”


“This is the very begin of this and there isn’t much content yet and the physics are far from realistic. The video is the best example for whats included so far. You guys are always welcome to give advises and ideas about what could be added to the game to make it as awesome as it can get!


The game needs a decent PC but there are changeable graphic options at startup so it should run on most of the PCs.”

If you’re unfamiliar with Nvidia FleX, it’s a particle simulator. It’s used oftentimes for mass liquid or soft body simulation… like impressionable skin or water waves. Soft-body physics can be extremely taxing on hardware and Nvidia has been working quite hard to find ways to ease the processing requirements for liquid, particle and soft-body physics. You can get an idea of how it’s used and what the technology looks like in the demonstration video below.

For now, Rathren explains that a demo is in the works for Boob Simulator, but he hasn’t released it yet because he doesn’t want anyone to steal his content before he’s at least set a lot of the groundwork in place. You can see what he has to offer so far in the video below, which could be labeled NSFW if seeing bare breasts jiggle is an offensive thing for you.

The project is currently being funded through Rathren’s Patreon. He has plans on releasing a demo soon enough with leap motion support, VR support, FleX liquid simulation and an editor so gamers can change the different sizes, shapes, textures and density of the boobs.

Later on in development he has plans to add a reactive face when the boobs are touched, as well as music, collision sounds and different skin materials.

It’s obvious some people might instantly yell “Perv!” but one thing to keep in mind is that Rathren could technically design an API out of this and distribute it separately from his game as a plug-in for the Unreal Engine 4. In this way, game developers could easily load up the API and have easily adjustable boob physics for their game, tech demo or prototype.

Anyway, discussion and suggestions are taking place for Boob Simulator on Hongfire or Game Vixen Zone, and Rathren is expecting to update and release new content on a monthly basis.


Billy has been rustling Jimmies for years covering video games, technology and digital trends within the electronics entertainment space. The GJP cried and their tears became his milkshake. Need to get in touch? Try the Contact Page.

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