ST_Volume
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## Name

ST_Volume — Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.

## Synopsis

`float ST_Volume(`geometry geom1`)`;

## Description

Availability: 2.2.0

This method needs SFCGAL backend.

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).

This method implements the SQL/MM specification. SQL-MM IEC 13249-3: 9.1 (same as ST_3DVolume)

## Example

When closed surfaces are created with WKT, they are treated as areal rather than solid. To make them solid, you need to use ST_MakeSolid. Areal geometries have no volume. Here is an example to demonstrate.

    SELECT ST_Volume(geom) As cube_surface_vol,
    	ST_Volume(ST_MakeSolid(geom)) As solid_surface_vol
      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_vol | solid_surface_vol
    ------------------+-------------------
                    0 |                 1

## See Also

ST_3DArea, ST_MakeSolid, ST_IsSolid

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