Which is Cheaper?   How do you manage easily and effectively?

Do NOT resort to having mutliple files with some structures deleted in one and others deleted in another.

Rather than having to maintain separate files for different design scenarios, OpenRoads Drainage incorporates the longstanding OpenFlows (Haestad) Active Topology Alternatives capability. 

Active Topology Alternatives are essentially Subsets of the structures in a design file.  They take full advantage of the property inheritance of the Alternatives.  

All the structures remain in a single file, no separate file is necessary. Each Structure has an IsActive? property in each Active Topology Alternative..

The cyan structures are in both Topology Alternatives (including all the inlets).  The grey pipes are in one or the other.  The grey crossing pipes are in the Single Trunk Alternative. The grey right-side pipes are in the Dual Trunk Alternative.

Dataset: Drainage-TwinTrunkTopology.dgn

Video: Topology: Single vs. Dual Trunks