Servo Force

118 Servo Force (Go to Video Tutorials)

Introduction

From Miarmy 2.7, we introduced the servo force. It’s able to simulate the internal forces from agents itself. Instead of simple rag-doll "dead man", servo force simulates the muscle force and it can drive your agent to target animated pose/action after the agents enabling dynamics. And it can achieve more lifelike internal/external spontaneous physical simulation, such as some agents falling and struggling from cliff, self-restitution.

Under the Hood

Traditionally, after agent enable dynamics, the agent will act like a rag doll (dead body) no any internal force inside, and just influence by gravity or other outside forces. This is not lifelike and non-realistic.

However, with servo force, we can add force to each joint and this kind of internal force can rotate each rigid body of rag doll to desire pose or animation sequence.Servo force use each frame action data as the target pose/animation, and push each dynamic body from to the target.

Please check the below image, after agent enabling dynamics, agent will be took over by dynamics system and turn into orange joint chain, the red dots between each dynamic body are dynamic joints. Please notice at this time the blue chain is the action data in memory, and our dynamic joint will push the dynamic body to the same angle of the action data.

So in below image, the orange chain will finally be pushed to blue angles, whereas it also can be influenced by outside forces like gravity or push force. We can easily simulate the result like agent pushed by outside force and still perform stuggling behavior and this behavior is controlled by internal force not.

blue action data rotate, orange: dynamic rigid body, red: dynamic joint

Example

Servo force can be used very wide range, mainly it used for:

    1. Agents struggling while falling or pushed put in the air

agent stuggling after enable dynamics

    2. Agents pose restitution such like 2 boxer fight each other

agent self restitution when hit by obstacle

Channels

The servo force channel is very simple, after enable dynamics for full body or partial bodies

servo.force