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How does a ragdoll/Physics asset control a simulated SkeletalMesh?

I been working with ragdolls lately, and just wondering how they work under the hood.

You assign Physics bodies to bones, and connect them with constraints.

Are these bodies just attached rigidbodies on the bones?

And are the constraints “overwriting” the joints of the skeleton?

If so, does the Phyics asset create a new “ragdoll skeleton” for the simulation, or just retargets the original one?

How does it deal with the weightpaint data for each bone?

Basically, the bodies are just definitions that you need to match up to the skeleton (mostly.manually) and seemingly are created automatically based on weight paint.

the constraints cannot overwrite the skeleton joints. They work with them regardless of where they are positioned.
The limit the rotation, and twist of the joint according to how you set up the constraint.

There is no retargeting happening. Its just a specification that alters how skeletal meshes react to physics influences.

The phat asset doesn’t really deal with the weight paint (other than possibly deriving capsule size from jt).

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What do you mean by definitions?

Definition(s): the degree of distinctness in outline of an object.
In this case the definition is the capsule/box/sphere area that you place onto the skeleton to simulate the area of the bone.