SELECT     dbo.BaseTable.ID, dbo.BaseTable.Color, dbo.BaseTable.Material, dbo.BaseTable.ComputedCol, dbo.BaseTable.User_id AS User_id1, 
                      dbo.Rights.User_id AS User_id2, dbo.Rights.Group_id, dbo.Rights.Chtenie, dbo.Rights.Zapis
FROM         dbo.BaseTable INNER JOIN
                      dbo.Rights ON dbo.BaseTable.User_id = dbo.Rights.User_id
WHERE     (dbo.Rights.User_id = USER_ID()) OR
                      (dbo.Rights.Group_id = CASE WHEN USER_ID() = '6' THEN 3333444 ELSE 0 END)

CREATE TRIGGER InsteadTrigger on InsteadView
INSTEAD OF INSERT
AS
BEGIN
  --Build an INSERT statement ignoring inserted.ID and 
  --inserted.ComputedCol.
  INSERT INTO BaseTable
       SELECT Color, Material
       FROM inserted
END;