The spatial reference of a Geometry object coming from MultiPatchBuilderEx.ToGeometry() is null even if the MultiPatchBuilderEx does have a spatial reference.

Solución alternativa

Consider the following code:

        var multi = new MultipatchBuilder(mpb.ToGeometry() as Multipatch);

        multi.SpatialReference = gda94;

        mutltipatch = multi.ToGeometry();

where mpb is a MultipatchBuilderEx object and GDA94 is a spatial reference. By getting the geometry of the mpb and sending that as a parameter for the Multipatch Builder constructor, the user can set the spatial reference of the multipatch geometry to whatever the user wants and then use the ToGeometry() method to get a geometry object with a spatial reference.

Pasos para reproducir