public bool inflateMesh { get; set; }

The physics engine imposes restrictions on the number of vertices and faces of convex meshes used for collisions. For that reason, the minimum-volume convex mesh automatically generated from the original non-convex mesh may not be suitable for use in physics. In order to address that, the mesh inflation can be used. It effectively extends the source data by a margin of MeshCollider.skinWidth and bevels the sharp edges so that the resulting mesh suits physics better.

Note: Setting this to true can decrease the accuracy of the collision mesh. Inflating a MeshCollider creates a new instance of the input mesh. This takes additional memory.