You should divide your project data across multiple drawings using a strategy that both protects data integrity and supports ease of access.
In AutoCAD Civil 3D, there is one master copy of each project object (such as a surface, alignment, profile, or pipe network), and that master copy is stored in a source drawing that is stored in the project’s Vault database. There are virtually no restrictions on how many project objects you can store in the same drawing, but there are some factors you should consider.
A key determining factor in how you partition your project data is the ability of team members to create and modify project data when they need to. Because only one person can edit a drawing at a time, placing the master copy of every project object into the same drawing is too restrictive for a collaborative environment. In general, spreading your project objects across many drawings makes more sense than crowding many objects into fewer drawings.
For each project object, create a separate drawing that contains the geometry of the project object and, if needed, related project objects. Consider placing each surface in a separate drawing. At the very least, consider placing a key surface, such as an existing ground surface, in its own drawing. You should avoid placing all your project alignments in the same drawing.
The function of a drawing should match its content. If a drawing contains the master copy of a surface object, that drawing shouldn’t also be a plan profile sheet. Keep project object geometry in its own drawing and create separate drawings for viewing and annotating read-only copies of the geometry.
It is important to understand that a single project must contain all the data that is required for that project. A drawing cannot contain references to more than one project at a time.
Adhering to a consistent naming convention will make the drawings that contain master copies of project objects easy to identify. Name a drawing that contains a project surface with the same name as the surface; name a drawing that contains a project alignment with the name of the alignment. Store project drawings in appropriately named folders. For more information see Project Folders.
Develop procedures that minimize the number of shared project objects. Make sure that team members understand that when adding or checking in a drawing, they should not share an object unless it is needed by others.