[postgis-tickets] [PostGIS] #4270: ST_3DIntersects says 'no' despite geometries intersecting

[PostGIS]

#4270: ST_3DIntersects says 'no' despite geometries intersecting
--------------------+---------------------------
 Reporter:  tilt    |      Owner:  colivier
     Type:  defect  |     Status:  new
 Priority:  medium  |  Milestone:  PostGIS 2.5.2
Component:  sfcgal  |    Version:  2.4.x
 Keywords:          |
--------------------+---------------------------
 This ticket is a follow up on a question on stackexchgange:
 [https://gis.stackexchange.com/questions/293619/st-3dintersects-says-no-
 despite-geometries-intersecting?noredirect=1#comment471093_293619]

 Considering the following query I expect both geomb and geomc to 3D
 Intersect with geoma. According to postgis, only geomc intersects.
 Unfortunately I can't come up with a more simplified polygon as an
 example, this situation seems largely to depend on the configuration of
 the polygon.


 {{{
 WITH data AS (
 SELECT
 ST_SetSrid(ST_GeometryFromText('
 POLYGON Z ((
     122409.416 489410.194 6.64975853832649,
     122404.759 489412.266 3.76021877729423,
     122407.18 489417.708 3.82360012934401,
     122405.377 489418.511 2.70471051793069,
     122406.754 489421.606 2.74081838637221,
     122408.218 489420.954 3.64933000361367,
     122409.263 489423.303 3.67668436361495,
     122407.787 489423.959 2.76102260948305,
     122409.313 489427.389 2.80101513611236,
     122411.091 489426.598 3.90419939305872,
     122411.172 489426.781 3.9061156669998,
     122409.45 489427.547 2.83769648670792,
     122410.905 489430.819 2.87547799988339,
     122412.594 489430.067 3.92357220158512,
     122413.511 489432.131 3.94697470225165,
     122411.723 489432.926 2.83768486408258,
     122413.229 489436.312 2.87694266543155,
     122414.931 489435.555 3.93292998257874,
     122415.345 489436.484 3.94412204281057,
     122420.157 489434.343 6.9298432176791,
     122409.416 489410.194 6.64975853832649
 ))
 '),28992) as geoma,


 ST_Extrude(ST_SetSrid(ST_GeometryFromText('
 LINESTRING Z (
     122412.982 489429.097 0,
     122414.559 489432.685 0
 )
 '),28992),0,0,10) as geomb,
 ST_Extrude(ST_SetSrid(ST_GeometryFromText('
 LINESTRING Z (
     122414.559 489432.685 0,
     122412.756 489433.477 0
 )
 '),28992),0,0,10) as geomc
 )


 SELECT
 ST_3DIntersects(geoma,geomb) ab,
 ST_3DIntersects(geoma,geomc) ac
 FROM data;
 }}}

 Results in: f;t

 I guess I should look at sfcgal for the culprit.

 Please note: the given geoma above is non-planar because of rounding when
 exporting to text. In the database it shows ST_IsPlanar(geoma) as true and
 gives the same results. On top of that, in the database running
 ST_3DIntersection on geoma vs. geomb and geoma vs. geomc both give a good
 result. This is not replicable here because of non-planarity.

 The situation is perhaps better described in the attached picture, where
 geoma is blue, geomb is red and geomc is green. The geometries in the
 image have been Tesselated for display purpose only.

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/4270>
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