60 lines
4.0 KiB
Markdown
60 lines
4.0 KiB
Markdown
# Navigation Samples
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The Navigation Samples showcase various usages of the NavMesh. They contain eight samples:
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1. Multiple Agent Sizes: Demonstrates how a different radius on an agent type can change the way agents navigate through the same scene.
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2. Drop Plank: Demonstrates dynamically changing walkable paths by allowing the player to add walkable planks by pressing space.
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3. Free Orientation: Demonstrates a controllable agent that can walk on a tilted plane.
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4. Sliding Window Infinite: Demonstrates a controllable agent that can walk through a dynamically created world that gets updated to simulate infinity as the agent walks through it. The NavMesh is only built in some set bounds that follow the agent.
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5. Sliding Window Terrain: Demonstrates a controllable agent that can walk through a terrain for which the NavMesh is only generated within a set distance of the agent.
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6. Modify Mesh: Demonstrates agents walking aimlessly on planes whose mesh can be modified dynamically by the player.
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7. Dungeon: Demonstrates a controllable agent that can walk through a maze generated from pre-baked tiles that connect to each other at runtime. The link traversal animation can be modified with some presets (teleport, normal speed, parabola, curve).
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8. Height Mesh: Demonstrates two agents walking down stairs. The environment on the left uses `NavMeshSurface` with a Height Mesh which allows the agent to snap to each step in the stairs as it goes down. The environment on the right uses a `NavMeshSurface` with no Height Mesh; the agent simply slides down the stairs.
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Note that some of these samples require that the `Packages/manifest.json` file of your project [references](https://docs.unity3d.com/Manual/upm-manifestPrj.html) the following default modules:
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```
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"com.unity.modules.physics": "1.0.0",
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"com.unity.modules.terrain": "1.0.0",
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"com.unity.modules.terrainphysics": "1.0.0"
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```
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# Introduction to NavMesh
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The Navigation package allows you to set up pathfinding AI in your Unity project. Two fundamental concepts of pathfinding are (1) agents and (2) world representation.
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1. An agent is a game entity that travels autonomously between two points in a scene. In Unity, a GameObject can be turned into a navigation agent by adding a `NavMeshAgent` component to it.
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2. World representation is what allows the pathfinding program of an agent to understand the traversable surfaces of a world. It is a simplification of a 3D world. In Unity, a traversable surface is represented as a mesh of polygons which we refer to as NavMesh.
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To convert some or all of the geometry in your scene into a surface that is traversable by an agent, you can use the `NavMeshSurface` component. However, you must also generate the data of the `NavMeshSurface` by using the `Bake` button in the Inspector. The process of baking is what actually creates a representation of the geometry in your scene that agents and their pathfinding program can understand.
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Whenever there are modifications done to the scene's geometry that can impact the navigation, the related `NavMeshSurface` component must be rebaked. The baking process is not done automatically because it can be a long process depending on the size and complexity of the input geometry. Note that baking cannot be done from the Inspector during Playmode.
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In order for an agent to move, it must know its destination. In Unity, the destination of a `NavMeshAgent` can be set through code with the `destination` property or the `SetDestination()` method. You can find an example of this in the `ClickToMove` script.
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For more information, refer to the [AI Navigation package manual](https://docs.unity3d.com/Packages/com.unity.ai.navigation@latest).
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# Agent Types
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The following agent types are created and used by the samples:
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1. Name: Humanoid for Navigation Sample
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Radius: 0.5
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Height: 2.0
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Step Height: 0.75
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Max Slope: 45
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2. Name: Ogre for Navigation Sample
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Radius: 1.0
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Height: 2.0
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Step Height: 0.4
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Max Slope: 36
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