To control how levels and grids display in project views, adjust their 2D and 3D extents.
This video demonstrates the following:
Levels and grids have both 3D and 2D extents defined when they are placed in a project. By default, the 2D and 3D extents of the datums are in the same position. Making changes to these extents affects how levels and grids are displayed in your project views.
The 3D extents of the datum represent the model extents. If a change is made to the 3D extents, this change is reflected in all of the views. For example, when Grid Line 1 is modified in the elevation, it changes in the other elevation and disappears from the plan views. The other grids are locked to Grid 1, so they are changed as well.
In order for a grid to be visible in a plan view, the grid's 3D extents must intersect the level datum for that plan. For example, if the 3D extents of the grid are moved down but not across the level 1 datum, the grids are displayed in the Level 2 plan but not in the Level 1 plan. Once the grids are crossing the Level 1 datum in the elevation, they are visible again in the Level 1 plan.
To display the grids in the plan views, but not have grid lines on top of the elevation view, you can modify the 2D extents of the grid independently from the 3D extents.
Select a grid line and click the 3D/2D setting for the grid. With the grid now set as a 2D element, changes made to it will be reflected in the current view only. The 3D extents of the grid are not modified and are represented by a dashed line with a hollow dot.
If you switch multiple grids to 2D before making changes, the 2D extents are locked and will move together. 2D extents of grids and levels are view-specific and must be positioned in each view.
Display of levels is controlled in a similar way to grids. Use 2D and 3D extents to adjust how datums are displayed in the views of your Revit LT project.