In Unreal Engine, what if the simulation physics option of static mesh body is gray?

The solution is: double-click to open the static grid body, click the collision menu above, add the collision according to the actual demand, save, and then come back to see that the simulation physics option is ready to click.

Official explanation:

If true, this body will use simulation. If false, will be ‘fixed’ (ie kinematic) and move where it is told. For a Skeletal Mesh Component, simulating requires a physics asset setup and assigned on the SkeletalMesh asset. For a Static Mesh Component, simulating requires simple collision to be setup on the StaticMesh asset.


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