4.9 KiB
4.9 KiB
Using NavMesh Agent with Other Components
You can use NavMesh Agent, NavMesh Obstacle, and Off Mesh 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 colliders 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 Rigidbody 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 time 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 Motion 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