Name
CG_3DDifference — Perform 3D difference
Synopsis
geometry CG_3DDifference(geometry geom1, geometry geom2);
Descrizione
Returns that part of geom1 that is not part of geom2.
Availability: 3.5.0
Questo metodo richiede il backend SFCGAL.
Questo metodo implementa la specifica SQL/MM. SQL-MM IEC 13249-3: 5.1
Questa funzione supporta il 3d e non distrugge gli z-index.
Questa funzione supporta le Polyhedral Surface.
Questa funzione supporta i Triangoli e le Triangulated Irregular Network Surfaces (TIN).
Esempi
3D images were generated using PostGIS ST_AsX3D and rendering in HTML using X3Dom HTML Javascript rendering library.
SELECT CG_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
50, 'quad_segs=2'),0,0,30) AS geom1,
CG_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
50, 'quad_segs=1'),0,0,30) AS geom2;
 Original 3D geometries overlaid. geom2 is the part that will be removed. |
SELECT CG_3DDifference(geom1,geom2)
FROM ( SELECT CG_Extrude(ST_Buffer(ST_GeomFromText('POINT(100 90)'),
50, 'quad_segs=2'),0,0,30) AS geom1,
CG_Extrude(ST_Buffer(ST_GeomFromText('POINT(80 80)'),
50, 'quad_segs=1'),0,0,30) AS geom2 ) As t;
 What's left after removing geom2 |