Fullbody VR attemp and questions

Guys, I want to acheive this posted by Jonas:

He replied in the commented that he acheived it using IKinema. I decided to try to make the similar effect using UE4’s native FABRIK node, here’s what I did so far(not so good but made some progress):

  1. Create a ThirdPerson Project

  2. Edit the ThirdPersonCharacter Blueprint and add three Transform type variables, check Editable and “Show 3D widget”. So they represent left hand, right hand and head in the game

  3. Edit the ThirdPerson_AnimBP,

    First the Event Graph:

Then the Anim Graph:

Note that the “Effector transform space” property of the FABRIK node has to be “World Space”!

You can try the result like this:
Click the ThirdPersonCharacter in the scence, you’ll find three “sockets” at the center of the human body(stacked together at first), click and move them one by one to the proper place, you can find it work (at certain level, questions will be raised at the end of this post)
I believe the three sockets can be driven by htc vive controllers and hamlet in some way(haven’t tried yet).

Here're the problems:
  1. The rotation doesn’t work right, it’ll go crazy if i rotate the “sockets”.

  2. How can I drive the character’s position and rotation, or even better, make the character play walk anim and rotating anim when user really moves and turns with the controller and hamlet.

Need help guys

Here’s the project file, please open with 4.13

Are you using “Compose Transform” with the inverse transform of your playermesh to the head, left and right hand?