The Mesh Collider takes a Mesh Asset and builds its Collider based on that Mesh. It is more accurate for collision detection than using primitives for complicated Meshes. Mesh Colliders that are marked as Convex can collide with other Mesh Colliders.
|Convex||Enable the checkbox to make the Mesh Collider collide with other Mesh Colliders. Convex Mesh Colliders are limited to 255 triangles.|
|Is Trigger||Enable this checkbox to make Unity use this Collider for triggering events, and the physics engine ignore it.|
|Cooking Options||Mesh Cooking オプションを有効または無効にします。このオプションは、物理エンジンがメッシュを処理する方法に影響を与えます。|
|None||Disables all of the Cooking Options listed below.|
|Everything||Enables all of the Cooking Options listed below.|
|Cook for Faster Simulation||Makes the physics engine cook Meshes for faster simulation. When enabled, this runs some extra steps to guarantee the resulting Mesh is optimal for run-time performance. This affects the performance of the physics queries and contacts generation. When this setting is disabled, the physics engine uses a faster cooking time instead, and produces results as fast as possible. Consequently, the cooked Mesh Collider might not be optimal.|
|Enable Mesh Cleaning||Makes the physics engine clean Meshes. When enabled, the cooking process tries to eliminate degenerate triangles of the Mesh, as well as other geometrical artifacts. This results in a Mesh that is better suited for use in collision detection and tends to produce more accurate hit points.|
|Weld Colocated Vertices||Makes the physics engine remove equal vertices in the Meshes. When enabled, the physics engine combines the vertices that have the same position. This is important for the collision feedback that happens at run time.|
|Use Fast Midphase||Makes the physics engine use the fastest mid-phase acceleration structure and algorithm available for your output platform. When you enable this option, the physics engine uses a faster algorithm that doesn’t require any R-Trees for spatial access. If you encounter mid-phase issues at runtime on some platform, you can still disable this option to use the slower legacy mid-phase algorithm instead.|
|Material||使用する 物理マテリアル への参照。物理マテリアルによりコライダーが他と衝突したとき、どのように相互作用するかが決定されます。|
The Mesh Collider builds its collision representation from the Mesh attached to the GameObject, and reads the properties of the attached Transform to set its position and scale correctly. The benefit of this is that you can make the shape of the Collider exactly the same as the shape of the visible Mesh for the GameObject, which creates more precise and authentic collisions. However, this precision comes with a higher processing overhead than collisions involving primitive colliders (such as Sphere, Box, and Capsule), so it is best to use Mesh Colliders sparingly.
Faces in collision meshes are one-sided. This means GameObjects can pass through them from one direction, but collide with them from the other.
Details about underlying algorithms and data structures used by mesh colliders can be found at PhysX documentation.
Mesh cooking changes a normal Mesh into a Mesh that you can use in the physics engine. Cooking builds the spatial search structures for the physics queries, such as Physics.Raycast, as well as supporting structures for the contacts generation. Unity cooks all Meshes before using them in collision detection. This can happen at import time (Import Settings > Model > Generate Colliders) or at run time.
When you generate Meshes at run time (for example, for procedural surfaces), it’s useful to set the Cooking Options to produce results faster, and disable the additional data cleaning steps of cleaning. The downside is that you need to generate no degenerate triangles and no co-located vertices, but the cooking works faster.
If you disable Enable Mesh Cleaning or Weld Colocated Vertices, you need to ensure you aren’t using data that those algorithms would otherwise filter. Make sure you don’t have any co-located vertices if you have disabled Weld Colocated Vertices, and when you enable Enable Mesh Cleaning, make sure there are no tiny triangles whose area is close to zero, no thin triangles, and no huge triangles whose area is close to infinity.
Note: When you set the Cooking Options to any other value than the default settings, it means the Mesh Collider must use a Mesh that has an isReadable value of
GameObjects that have a Rigidbody component only support Mesh Colliders that have Convex option enabled: the physics engine can only simulate convex mesh colliders.
You should not modify mesh geometry that is used for colliders because the physics engine has to rebuild an internal mesh collision acceleration structure every time you change the mesh. This causes a substantial performance overhead. For meshes that need to collide and change at runtime, it is often better to approximate the mesh shape with primitive colliders like capsules, spheres and boxes.
Optimization tip: If a Mesh Collider only uses a Mesh, you can disable Normals in Import Settings, because the physics system doesn’t need them.
2018–10–12 Page amended
Mesh Cooking Options は 2017.3 で追加NewIn20173
バージョン 2018.1 の更新機能
読み込み/書き込み可能な設定に関する制限を 2017.3 で更新
Inflate Convex Meshは、2018.3 で非推奨に。なぜなら、新しい凸状の計算アルゴリズム (Quickhull) が入力メッシュの不完全さに対してより寛容であるため。