I am experiencing a problem where my character’s collision capsule is detaching from its mesh when I enable physics. Its very easy to reproduce - make a new 3rd person template, and do the following:
enable physics on the character’s mesh component by using “Set All Bodies Below Simulate Physics” with “root” specified as the bone (for the record, this is the UE4 mannequin which has an unweighted root bone)
delay for 3s, so your character has a chance to ragdoll
Turn physics on the mesh back off
You now have a separated mesh and capsule because the mesh has lost its parent (the capsule). This seems like extremely odd behavior - the root bone should still be in the capsule after all.
For reference, if you change “root” to another bone down the tree like “hand_r” the parent will NOT be lost.
You can repair the situation using “AttachTo” to reparent the mesh to the capsule after you turn physics back on. But is this a bug?
Workaround in case your mesh has a transform relative to the character BP’s capsule (mine was -18,10,-64 for location, 0,0-90 for rotation, 6,6,6 for scale), and you want to reset it back to that:
Its not much if an issue, its more by design.
And it was never a bug, just an engine feature.
The character capsule does not simulate physics with the mesh.
The mesh has to be released from the capsule to be free to ragdoll/simulate (if you use root that is).
What you normally do if you have to get back up and walk as a character is that you script things so that the capsule is kept in pair with the root bone while the simulation is playing out.
You then re-attach and resume normal ABP processing.
In unreal characters, all the capsule data/actor position rotation etc is complitely reliant and related to the root bone, even when root motion is off.
After ragdolling, you may want to place the capsule at the correct root bone position, but be careful about the rotation.
You want to retain the Z UP, if you mix it up you’ll only have issues…
