Hmm, partially answering my own question, but it's obvious the output is not 2D, but I can't say I quite understand the product it is creating... .
Best, Steve On Sat, Dec 7, 2013 at 5:55 PM, Stephen Mather <[email protected]>wrote: > Hit send too soon... > > Hi All, > > Digging SFCGAL... . Quick question-- is ST_MinkowskiSum a 2D calculation > of the Minkowski Sum when non-polyhedral surfaces are fed in? For example, > I tried this: > > WITH pointt AS ( > > SELECT ST_MakePoint(0,0,0) AS the_geom > > ), > > buffered AS ( > > SELECT ST_Buffer(the_geom, 30, 20) AS the_geom FROM pointt > > ), > > rotatedOnItsSideX AS ( > > SELECT ST_RotateX(the_geom, 0.25 * pi()) AS the_geom from buffered > > ), > > minkowski_sum AS ( > > SELECT ST_MinkowskiSum(x.the_geom, b.the_geom) AS the_geom FROM > > rotatedOnItsSideX x, buffered b > > ) > > SELECT ST_AsText(the_geom) from minkowski_sum; > > > I get: > > > MULTIPOLYGON(((-60 -7.45012945754965e-14,-59.9075200119938 > -2.35377287183542,-59.8150400239877 -4.01814163088313,-59.538170229848 > -6.35740271025471,-59.2613004357083 -8.01151008244411,-58.8017478297844 > -10.3218370469144,-58.3421952238606 -11.9554849102494, (...) > > > Thanks, > > Best, > > Steve > > > > > On Sat, Dec 7, 2013 at 5:51 PM, Stephen Mather > <[email protected]>wrote: > >> Hi All, >> >> Digging SFCGAL... . Quick question-- is ST_MinkowskiSum a 2D calculation >> of the Minkowski Sum when non-polyhedral surfaces are fed in? For example, >> I tried this: >> >> WITH pointt AS ( >> >> SELECT ST_MakePoint(0,0,0) AS the_geom >> >> ), >> >> buffered AS ( >> >> SELECT ST_Buffer(the_geom, 30, 20) AS the_geom FROM pointt >> >> ), >> >> rotatedOnItsSideX AS ( >> >> SELECT ST_RotateX(the_geom, 0.25 * pi()) AS the_geom from buffered >> >> ), >> >> minkowski_sum AS ( >> >> SELECT ST_MinkowskiSum(x.the_geom, b.the_geom) AS the_geom FROM >> >> rotatedOnItsSideX x, buffered b >> >> ) >> >> SELECT 1 as gid, ST_AsText(the_geom) from minkowski_sum; >> >> >> >
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