Using Mesh Colliders

A Mesh Collider builds collision geometry directly from your 3D model — every polygon, curve, and contour. Precise, but expensive. Use them for complex static geometry where multiple Box/Capsule colliders would cost more.

Concave vs Convex

Concave (default): Matches your mesh exactly — bumps, dents, indents. Static or kinematic only. Two concave colliders can’t collide; only convex shapes can bump into them.

A concave Mesh collider on a banana-shaped GameObject. (Unity — Manual: Mesh colliders)

Convex: Shrink-wraps your mesh into a smooth hull. Less accurate, faster. Can be dynamic, static, or kinematic. Can collide with other convex colliders.

A convex Mesh collider on the same banana-shaped GameObject. (Unity — Manual: Mesh colliders)

Enable “Is Convex” in the Inspector to switch. Use concave for static walls and props; use convex when the object needs to move or be thrown.

When to Use

Do use:

• Static scene geometry (walls, rubble, terrain rocks)
• Complex props that’d need 5+ primitives to approximate
• Convex shapes that move (shields, helmets, projectiles)

Don’t use:

• Deforming meshes. Recalculating geometry every frame kills performance.
• Simple shapes (use Box/Capsule instead).
• Dynamic objects in high-traffic areas.

Kinematic + Mesh Collider

Set Is Kinematic = true on the Rigidbody to stop physics from controlling the object. You move it via script or animation instead.

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Perfect for barriers and doors:

• Door has Mesh Collider (concave) + Rigidbody (Is Kinematic enabled).
• Script moves it via Transform.position.
• Collider remains precise; player can’t clip through edges.
• No gravity, no physics interference — full control.

Use this pattern for animated doors, moving platforms, rotating gears with complex geometry.

Inspector Settings (Cooking)

• Mesh: The mesh asset (must be read-write).
• Is Convex: Concave or convex.
• Cooking Options: PhysX builds collision geometry once at load time. Higher quality = more accurate, slower compile. Don’t change unless you hit accuracy bugs.
• Inflate Mesh: Slightly expands the collider. Helps with thin geometry.

Cooking happens once per scene load. Not per-frame unless the mesh deforms.

The Profiler Test

Mesh Colliders look efficient on paper but don’t always win. Profile before shipping:

• Physics Profiler (Window > Analysis > Profiler > Physics)
• Compare mesh vs. compound colliders (multiple primitives)
• Measure FPS and per-frame physics cost
• Use whichever is faster

Bottom Line

Mesh Colliders solve complex static geometry precision without manual labor. But they’re not free. Use them for static elements and convex moveable shapes. Enable Is Kinematic for animated barriers. Always test against alternatives.