GameObject.sceneCullingMask

Description

The Scene culling mask defined for the GameObject. (Read Only)

Unity uses SceneCullingMasks to determine which scene to render the GameObject in. The sceneCullingMask is a bitfield stored as an unsigned 64-bit integer ulong. Cameras only render an object in a scene if the bits set on the Scene's mask (retrievable withEditorSceneManager.GetSceneCullingMask) match those in the object's sceneCullingMask.

using UnityEngine;
using UnityEditor.SceneManagement;

[ExecuteInEditMode]
public class ExampleClass : MonoBehaviour
{
    
    void Start()
    {
        //Check if gameObject is visible in scene
        if(gameObject.sceneCullingMask == EditorSceneManager.GetSceneCullingMask(gameObject.scene))
        {
            Debug.Log("Object is visible");
        }
        else
        {
            Debug.Log("Object is not visible");
        }
    }
}

Additional resources: SceneCullingMasks, Camera.overrideSceneCullingMask, EditorSceneManager.SetSceneCullingMask