Transfer Physics Asset

This is a required step or the character mesh will horribly detach when any impact physics or ragdoll is applied.

Alternatively, if you want to keep your own physics asset, make sure the root bone has a kinematic shape that the pelvis is constrained to. Check PHAT_MoveIt to see what this looks like.

1. To get started go to MoveIt Content and duplicate /Models/Character/Mesh/PHAT_MoveIt to your project
2. Rename it then open it
3. Under "Preview Scene Settings" select your character. The Physics Asset will reopen with your new character assigned

Full Image

Full Image

Adjust Result

If any shapes don't fit well, adjust them

Validate

Press simulate in the physics editor and ensure the character crumples in a sensible manner

Bad Physics Asset Result

If your skeleton differs significantly from UE4 standard then you will likely get a very poor result. A tutorial is coming on how to create physics assets from scratch, but for now it might be best to mimic PHAT_MoveIt as close as possible while building the physics asset from scratch for your custom skeleton.