I’m struggling with the TopologyBuilder transformer and, since I’m sure my use case is quite common, I hope someone might be able to help me.
I want to extract the topological boundary polyline from polygons. In addition to the polyline geometry, I’d like to carry polygon attributes through to left and right-side attributes of each new polyline. For example, if my input polygons were countries of the world, I’d like my output polylines to be borders with each attributed with the country on each side. e.g. Left: France, Right: Germany.
I’ve got the polylines geometry coming out of the TopologyBuilder perfectly, but not so lucky on the attributes. I get _left_face and _right_face attributes coming out, but these edge IDs don’t seem to mean anything. They don’t relate to any input attributes, nor are the polygon table row id.
I’ve also tried “Generate List From Input Faces”, defined a list name, Selected Attributes, and my attribute field name. Sadly, none of these are populated on the output. Ideally, I would like attributes associated with the left and right of the line, rather than a list, anyway.
Any help appreciated!
/Warren
