Construct a buffer for a 3D point or linestring using ST_3DBuffer - PolarDB

ST_3DBuffer extends a 3D point or LineString by a specified radius to produce a closed mesh buffer.

Syntax

meshgeom ST_3DBuffer(geometry geom3d, float8 buffer_radius, boolean round_end default true, float8 smooth default 0.5)

Parameter	Type	Default	Description
`geom3d`	geometry	—	The input geometry. Accepts Point or LineString.
`buffer_radius`	float8	—	The buffer radius.
`round_end`	boolean	`true`	Controls the endpoint shape for LineString buffers. `true` adds a hemisphere cap at each endpoint. `false` leaves endpoints flat with no cap.
`smooth`	float8	`0.5`	Controls the triangle side length on the buffer surface. Valid values: `(0, 1]`. A smaller value produces finer triangles and a smoother surface that more closely approximates a curved surface. Requires `round_end` to be explicitly set.

Parameter dependency:

All examples use ST_AsText to display the MESHGEOM output as text.

Buffer around a Point (default parameters):

SELECT ST_AsText(ST_3DBuffer('POINT(0 0 0)', 2));

Output:

MESHGEOM(PATCH(INDEXSURFACE Z (VERTEX(0 0 2,-0.894427190999916 0 1.78885438199983,-0.447213595499958 ...

Buffer around a LineString with flat endpoints (`round_end=false`):

SELECT ST_AsText(ST_3DBuffer('LINESTRING(1 2 3, 0 0 4)', 0.5, false));

Output:

MESHGEOM(PATCH(INDEXSURFACE Z (VERTEX(1.43294188107951 1.89763792560716 3.22821773229382,1.30266373925419...

Buffer around a LineString with hemisphere endpoints and custom smoothness (`round_end=true`, `smooth=0.6`):

SELECT ST_AsText(ST_3DBuffer('LINESTRING(0 1 0, 1 3 2, 2 1 1)', 1, true, 0.6));

Output:

MESHGEOM(PATCH(INDEXSURFACE Z (VERTEX(-0.89885050178969 1.01131599079557 0.438109260099278...