ST_3DArea
Name
ST_3DArea — Computes area of 3D surface geometries. Will return 0 for solids.
Synopsis
    
     float
     
      ST_3DArea
     
     (
    
    geometry
    
     geom1
    
    
     )
    
    ;
   
Description
Availability: 2.1.0
   
    
   
   This method needs SFCGAL backend.
  
   
    
   
   This method implements the SQL/MM specification.
  
SQL-MM IEC 13249-3: 8.1, 10.5
   
    
   
   This function supports 3d and will not drop the z-index.
  
   
    
   
   This function supports Polyhedral surfaces.
  
   
    
   
   This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
  
Examples
Note: By default a PolyhedralSurface built from WKT is a surface geometry, not solid. It therefore has surface area. Once converted to a solid, no area.
SELECT ST_3DArea(geom) As cube_surface_area,
	ST_3DArea(ST_MakeSolid(geom)) As solid_surface_area
  FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
    ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
    ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
    ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
    ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
    ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);
 cube_surface_area | solid_surface_area
-------------------+--------------------
                 6 |                  0