Levels and Grids: The Datum Objects Everything Else Depends On

Levels and grids are datum objects — reference geometry, not building elements — but almost everything else in your model is anchored to one or both of them, directly or indirectly.

What levels actually control

Levels are parallel to the ground plane and are the main mechanism for managing a piece of content’s elevation (Z-location). Virtually every element you place has a Level parameter, and you can move an object from one level to another just by changing that property. Levels also act as constraints: walls and columns have top/bottom constraints that can be tied to a level, so they automatically update if that level’s elevation shifts.

One easy-to-miss rule: levels can only be seen and created in elevation and section views — you won’t find the Level tool available in a plan view.

What grids actually control

Grids organize and constrain elements, and — unlike levels — they’re only visible in views that are perpendicular to them. A north-south oriented grid shows up in plan views and in east-west elevations, not in a north-south elevation. If a grid seems to have “disappeared” in a particular view, check the view’s orientation relative to the grid before assuming something broke.

Two kinds of extents, and why the distinction matters

Both levels and grids have a 3D (analytic) extent and a 2D extent. The 3D extent determines the actual relationship — whether the datum truly intersects a level for associativity purposes. The 2D extent is purely visual: how far the line is drawn in a specific view. You can set the 2D extent short in one view while the 3D extent still runs the datum through several levels — the grid remains valid and associated everywhere, it just isn’t drawn full-length in every view. Don’t confuse “the grid line looks short here” with “the grid doesn’t reach this level.”

Because of this coupling, moving a datum cascades: move a level and connected walls/furniture move with it; move a grid and structural elements tied to it relocate. Once a project stabilizes, constrain or pin datum objects to stop accidental moves from rippling through the model.

Creating levels without drowning in views

When you create a new level, the “Make Plan View” option generates a corresponding plan view for it. Copying an existing level does not — which is exactly what you want when quickly laying out a dozen levels on a high-rise and don’t need a dozen new plan views cluttering the Project Browser. Levels can also exist purely as a reference (an intermediate landing, a mezzanine) with no plan view at all.

Common mistake

Creating a level for every slab offset, stair landing, or floor step “just to be safe.” You don’t need one — elements can be Z-offset from an existing level instead. Over-creating levels adds clutter to manage and can measurably slow down a large project; only add a level when it needs to be shown in documentation or manages a major part of the building. If you do batch-create plan views while setting levels up, use Close Inactive Views (Quick Access toolbar) afterward — leaving dozens of views open at once is its own performance hit.