For existing Drainage and Utilities, any data can be brought in and used in the design environment.
The most fully-integrated data would be OpenRoads Designer Drainage and Utilities design files. These would include 3D, spatially-accurate, fully-attributed smart BIM-ready graphics. They would simply be referenced in to the active design file. In standard Project File Setup, these existing utilities files would be referenced into the Project Container file for full integration into the project.
As part of the design setup process, other formats of existing utility data can be used.
"Unattributed" 3D pipes and structures can be referenced in. Though they may not yield information, they are still useful for spatial analysis and visual and programmatic conflict detection.
Attribution can be added via the Extract Utilities from Graphics tool, which requires only 2D or 3D linestrings to create physically representative 3D solids. 2D line work can be imported and draped relative to a surface.
Model Builder is a tool that takes any structured data schema (GIS, database, Excel, etc.) and creates 3D BIM-ready attributed solids.
These tools can be learned in an hour or two. Once converted to smart 3D utilities and referenced into design files, they are fully integrated into the "standard" Bentley Civil environment and workflows.
In the Drainage Modeling Learning Path, these classes are helpful: