I'm trying to make pipes from lines. It would probably be easier to make them elsewhere and import, but I'd like to do it in CE. I tried to use the graph layer and inserting a cylinder object but it's pretty messy - modifying the street construction rule would probably get me somewhere but I figured I better ask first.
Yes, I would recommend writing rules on street shapes.
You could create a graph network where the streetWidth is equal to the pipe width, and the sidewalk widths are set to 0. Then, you could apply a rule on the Street, Joint, Crossing, and Junction shapes to insert cylinders on each face. But, the cylinders might not look nice at the joins, so if you can accept square pipes, a rule that just extrudes the shape by the pipe width would be a simple way to model the pipe network.
Oh, that's right. Good point. The pipes will break open with the current extrude method (and extruding along world.y will keep some pipes together but will not work at all for vertical pipes). We are working on new functionality for the extrude method which would solve this problem. Sorry, I'm not sure if there is a good workaround for 2015.2.