🖖 If you FAQed up in Unity Engine, perhaps you'll find the answer here. 🖖

Unity: Shadows and Lights

How to fix ripples on surfaces/objects etc?

Try adjusting Bias and/or Normal Bias settings for the light source, for example:
Unity shadow ripples (resolve)

Unity: ECS (Entity Component System)

Why do entities appear in editor but not in the game build?

In the editor, the subscene with entities is loaded and ready to use, while in the build, you need to delay systems until it is fully loaded. For example:

public partial struct YourComponentSystem: ISystem 
void OnUpdate(ref SystemState state)
{
    if (SystemAPI.Time.ElapsedTime > 10)
    {
        foreach (RefRW<YourComponent> comp in SystemAPI.Query<RefRW<YourComponent>>())
        {
            // do stuff
        }
    }
}
 
 

public partial struct YourComponentSystem: ISystem

1 2 3 4 5 6 7 8 9 10	`void` `OnUpdate(ref` `SystemState state)` `{` `if` `(SystemAPI.Time.ElapsedTime > 10)` `{` `foreach` `(RefRW<YourComponent> comp` `in` `SystemAPI.Query<RefRW<YourComponent>>())` `{` `// do stuff` `}` `}` `}`

Why does the Rigidbody (Physics) stop working in main scene when using a subscene?

Probably at least one of your entities in the subscene (or prefabs turned into Entities) has a Rigidbody component attached.

Why aren't entities visible in scenes (either in the editor or at runtime)?

Perhaps you're missing the Entities Graphics package (if so, reload scenes after installing the package). Note that Entities Graphics doesn't support the Built-in Render Pipeline (at the moment, v1.2.1); it requires either URP or HDRP to function properly.