In the case of a Character Creator character, the bones you need are the cc_base_l_ribstwist and cc_base_r_ribstwist, and the settings I've found to work just fine are the ones in the image below. Next, add sphere colliders to your breast bones, and resize them, so they resemble the size of your character's breasts, and set the physics type as Simulated, activate the MassInKg and then set the values of the linear and angular dampening. To do this, select all the colliders in your hierarchy and set the physics type to Kinematic. We have to do this because, if we don't, the entire skeleton will react like a ragdoll due to some settings we will activate later. Using Character Creator made this very easy, since the skeleton already includes those bones.ДЇirst, you need to turn off the physics of all of your colliders. All you need is your Physics Asset and a bone structure that includes breast bones. You can see the video below to see what I mean.ДЄdding breast physics isn't as difficult in UE4. Since one of my mini-studio's current projects, 'Just Let Me Go,'В features a very realistic protagonist (thanks to Reallusion's Character Creator 3), she doesn't look right when she's moving around with a very rigid chest. For example, if your character is a pre-teen or a young girl, the character is wearing an armor, or if the type of game does not need that kind of detail (like a cartoony side-scroller like 'Mega Man' or a top-down action RPG with small characters like 'Diablo'), you don't need to add those details. I say 'may' and not 'will' is because breast physics are not always required. If you're working on a videogame with a female character, you may find yourself in the need to add breast physics to her.

Unreal engine 4 rpg tutorial