ST_Overlaps for 2 TIN geometries

Question

ST_Overlaps, ST_Contains, ST_Touches, ST_Within works for TIN with point data. But, when I try with 2 TIN it gives error. Could you please help me understand the reason for failure and how to fix it. I need comparisons only between TIN objects.

SELECT ST_Overlaps
('TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))'::geometry,
 'POINT(0.5 0 0.5)'::geometry);

SELECT ST_Overlaps
('TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))'::geometry, 
 'TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),((0 0.5 0,1 1 1,1 0.5 0.5,0 0.5 0)))'::geometry);

ERROR: Unknown geometry type: 15 - Tin
CONTEXT: SQL function "st_overlaps" statement 1

-Note: ST_3dIntersects works with 2 TIN objects

Answer 1

It is something of a hack, but you can use a the replace function on the TIN Zs, convert those to POLYGON Zs, and then use ST_Dump to extract the individual triangles as polygons. For example:

WITH 
    tin (id, geom) AS (
       SELECT (ST_Dump(
                  ST_GeomFromText(
                     replace(
                        'TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),
                        ((0 0.5 0,0 0 0,0 0.5 0.5,0 0.5 0)))'::text, 
                        'TIN Z', 'MULTIPOLYGON')))
               ).*), 
    tin1 (id, geom) AS (
        SELECT (ST_Dump(
                   ST_GeomFromText(
                     replace(
                         'TIN Z (((0 0 0,0 0 0.5,0 0.5 0.5,0 0 0)),
                          ((0 0.5 0,1 1 1,1 0.5 0.5,0 0.5 0)))'::text, 
                          'TIN Z', 'MULTIPOLYGON')))
                ).*)
 SELECT 
      a.id[0], 
      b.id[0], 
      ST_3dIntersects(a.geom, b.geom) 
    FROM tin a, tin1 b;

As there is no 3D equivalent of ST_Contains, you would have to ensure that your TINs are closed in 3D (ie, are solids) and use ST_3DIntersection of of the two TINs and compare against ST_Volume of each individual one.