Using NavMesh Agent with Other Components

You can use NavMeshA mesh that Unity generates to approximate the walkable areas and obstacles in your environment for path finding and AI-controlled navigation. More info
See in Glossary Agent, NavMesh Obstacle, and Off MeshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
See in Glossary Link components with other Unity components too. Here’s a list of dos and don’ts when mixing different components together.

NavMesh Agent and Physics

• You don’t need to add physics collidersAn invisible shape that is used to handle physical collisions for an object. A collider doesn’t need to be exactly the same shape as the object’s mesh - a rough approximation is often more efficient and indistinguishable in gameplay. More info
  See in Glossary to NavMesh Agents for them to avoid each other
  • That is, the navigation system simulates agents and their reaction to obstacles and the static world. Here the static world is the baked NavMesh.
• If you want a NavMesh Agent to push around physics objects or use physics triggers:
  • Add a Collider component (if not present)
  • Add RigidbodyA component that allows a GameObject to be affected by simulated gravity and other forces. More info
    See in Glossary component
    • Turn on kinematic (Is Kinematic) - this is important!
    • Kinematic means that the rigid body is controlled by something else than the physics simulation
• If both NavMesh Agent and Rigidbody (non-kinematic) are active at the same time, you have race condition
  • Both components may try to move the agent at the same which leads to undefined behavior
• You can use a NavMesh Agent to move e.g. a player character, without physics
  • Set players agent’s avoidance priority to a small number (high priority), to allow the player to brush through crowds
  • Move the player agent using NavMeshAgent.velocity, so that other agents can predict the player movement to avoid the player.

NavMesh Agent and Animator

• NavMesh Agent and Animator with Root MotionMotion of character’s root node, whether it’s controlled by the animation itself or externally. More info
  See in Glossary can cause race condition
  • Both components try to move the transform each frame
  • Two possible solutions
• Information should always flow in one direction
  • Either agent moves the character and animations follows
  • Or animation moves the character based on simulated result
  • Otherwise you’ll end up having a hard to debug feedback loop
• Animation follows agent
  • Use the NavMeshAgent.velocity as input to the Animator to roughly match the agent’s movement to the animations
  • Robust and simple to implement, will result in foot sliding where animations cannot match the velocity
• Agent follows animation
  • Disable NavMeshAgent.updatePosition and NavMeshAgent.updateRotation to detach the simulation from the game objects locations
  • Use the difference between the simulated agent’s position (NavMeshAgent.nextPosition) and animation root (Animator.rootPosition) to calculate controls for the animations
  • See Coupling Animation and Navigation for more details

NavMesh Agent and NavMesh Obstacle

• Do not mix well!
  • Enabling both will make the agent trying to avoid itself
  • If carving is enabled in addition, the agent tries to constantly remap to the edge of the carved hole, even more erroneous behavior ensues
• Make sure only one of them are active at any given time
  • Deceased state, you may turn off the agent and turn on the obstacle to force other agents to avoid it
  • Alternatively you can use priorities to make certain agents to be avoided more

NavMesh Obstacle and Physics

• If you want physics controlled object to affect NavMesh Agent’s behavior
  • Add NavMesh Obstacle component to the object which agent should be aware of, this allows the avoidance system to reason about the obstacle
• If a game object has a Rigidbody and a NavMesh Obstacle attached, the obstacle’s velocity is obtained from the Rigidbody automatically
  • This allows NavMesh Agents to predict and avoid the moving obstacle