Name
CG_3DBuffer — 计算几何体周围的三维缓冲区。
Synopsis
geometry CG_3DBuffer(geometry geom, float8 radius, integer segments, integer buffer_type);
描述
Generates a 3D buffer around the input geometry geom with a specified radius. The buffer is constructed in 3D space, creating a volumetric representation of the geometry's surroundings. The segments parameter defines the number of segments used to approximate the curved sections of the buffer, with a minimum value of 4 segments required. The buffer_type specifies the type of buffer to create: 0: Rounded buffer (default) 1: Flat buffer 2: Square buffer
Input geometry must be a Point or LineString.
可用性：3.6.0 - 需要 SFCGAL>= 2.0.0
该方法需要SFCGAL后端。
示例
SELECT ST_AsText(CG_3DBuffer('POINT(0 0 0)', 1, 8, 0));
-- Result: POLYHEDRALSURFACE Z (((0 0 1, 0.5 -0.5 0.71, 0 -0.71 0.71, 0 0 1)), ... )
下一张图片是通过将 ST_AsX3D 查询的输出粘贴到 X3D Viewer 中进行绘制的结果。
SELECT string_agg('<Shape
>' || ST_AsX3D(cgbuffer3d_output) || '<Appearance>
<Material diffuseColor="0 0.8 0.2" specularColor="0 1 0"/>
</Appearance>
</Shape
>', '');
segments=32（球形缓冲区）
SELECT CG_3DBuffer(ST_GeomFromText('POINT(100 90)'), 50,32,0);
|
5边形球
SELECT CG_3DBuffer(
ST_GeomFromText('POINT(100 90)'),
50,5,0);
|
32边球形
SELECT CG_3DBuffer(
ST_GeomFromText(
'LINESTRING(50 50,150 150,150 50)'
),
10,32,0);
|
32边方形
SELECT CG_3DBuffer(
ST_GeomFromText(
'LINESTRING(50 50,150 150,150 50)'
),
10,32,2);
|