While "Auto Sync" is checked, changes to the mesh will automatically be reflected in Unity. If Auto Sync is disabled, use the "Manual Sync" button to sync changes.
Checking "Sync Camera" will sync the camera in Metasequoia. "Camera Path" is the camera path in Unity.
Clicking "Import Unity Scene" will import the currently open Unity scene. Changes made to the scene can be reflected in real time.
Mirroring and smooting will be reflected in Unity.
However, "reflective surfaces where the left and right are connected" type mirroring is not supported.
Hidden objects in Metasequoia will also be hidden in Unity. Mesh details for hidden objects will not be sent to Unity, so when the number of objects in a scene makes sync heavy, making them hidden as appropriate should also speed up the sync process.
Materials will not be reflected in Unity, but they will be split into appropriate sub-meshes depending on the Material ID.
Subdivisions and metaballs will not be reflected in Unity until you freeze them.
Check "Sync Normals" to reflect vector changes supported by Metasequoia 4 versions.
Check "Sync Bones" to reflect bones supported by Metasequoia 4 versions. Checking "Sync Poses" will reflect the pose designated under "Skinning".