You might have wanted to create a map series of your model and realize it with View Frames in Civil 3D.
In the Model View you see all your View Frames and how they line up to each
other. To give an overview of where each View Frame is located in the model you
might want to create an overview map and plot it, but the View Frames are not
displayed in the Layout.
The solution to this is to check the Viewport Frame Type and set it to “Undefined”. After a REGENALL command the View Frames should be displayed in the Layout View and the overview map can be plotted.
To illustrate please see these two images:
View Frames in Model View
View Frames missing in Layout View
After selecting “Undefined” for View Port Type and a REGENALL the View Frames are displayed.