I'm new to 3D data and want to know what I should be searching for when I'm looking to find all the triangles in a 3D building mesh that fall within a 2D footprint.

The mesh comes from LiDAR and broken into 1km grids, the largest tile contains some 60m triangles there are 1,000 tiles to process. I'm familiar with Python/QGIS/PostGIS and this seems like a problem others must have faced but I'm not getting any leads so think I'm not looking for the right terms where I've looked for 3D spatial joins in QGIS and generating 3D bounding box in QGIS from 2D polygon

  • There are a bunch of 3D functions. If you are trying to find intersections with a 2D footprint, you can probably safely drop the z-coordinates, using ST_Forced2D. Or you could use [ST_3DIntersects(postgis.net/docs/ST_3DIntersects.html), but this will likely be much slower, even with a 3D spatial index. – John Powell Jul 5 at 9:34

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