[postgis-devel] Unexpected output from ST_AsX3D with PolyhedralSurfaceZ

[Regina Obe]

Tom,

 

Yah that looks wrong and I get the same bad rendering too and right rendering with the Tesellate.  Can you ticket this one and I'll take a look next chance I get.

 

http://postgis.net/support/

 

Thanks,

Regina

 

 

 

From: postgis-devel [mailto:postgis-devel-bounces at lists.osgeo.org] On Behalf Of Tom van Tilburg
Sent: Monday, January 18, 2016 11:25 AM
To: PostGIS Development Discussion <postgis-devel at lists.osgeo.org>
Subject: [postgis-devel] Unexpected output from ST_AsX3D with PolyhedralSurfaceZ

 

Im trying to display some extruded buildings as X3D but noticed that the output with concave buildings (U shaped) creates a convex faceset on the top and bottom of the building. This doesn't seem right.

 

When I tesselate first, and therefore go fom polyhedralsurfacez to TIN the output is allright.

You can try with and without tesselate yourself:

 

SELECT ST_AsX3D(ST_Tesselate(ST_Extrude(ST_GeometryFromText('Polygon((0 0, 0 10, 30 10, 30 0, 20 0, 20 5, 10 5, 10 0, 0 0))'),0,0,10)))

 

For completeness:

<X3D>

<Scene>

        <Viewpoint orientation='0.2 0 0 0.8' position='-10 -10 100'/> 

        <Background skyColor='1 1 1'/> 

        <Shape>

<!--PUT YOUR OUTPUT HERE, TESSELATED VERSION ALREADY INCLUDES SHAPE -->

</Shape>

    </Scene>

</X3D>

 

Best, Tom

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