Hi again,
I look at havok plugin code and I agree with you, it returns only world point and world normal of raycast result. I thought it was a bug because in the documentation hitPointWorld says : “Gets the hit point in the world” and hitPoint “Gets the hit point.” so when reading at it I assume that hitPoint was in local coordinates of the hitten body.
Doc here : Babylon.js docs
I made a small matrix/transform and I get my local coordinates.
Thanks again for the answers, bye.