Looking for DATUM for Revit? DATUM is also the name of our Revit architecture template and Revit plugins. This guide is about the datum elements in Revit itself.
01What a datum is in Revit
A datum is a plane the model is set out from. Revit has three: levels (horizontal planes, one per floor), grids (vertical planes, the structural axes) and reference planes (planes you place yourself, to draw on or to align to). Walls take their base and top from levels, columns are placed on grid intersections, and families and sketches are drawn on reference planes. Move a level, and every wall and floor on it moves with it. In the ribbon, Level and Grid sit together on the Datum panel of the Architecture tab; Reference Plane is on the Work Plane panel.
02Levels
Levels are drawn in an elevation or a section: Architecture → Datum → Level. With Make Plan View ticked in the Options Bar, Revit creates a floor plan (and a ceiling plan) for each new level. A level head in blue has views; a head in black has none.
- Copy and Array make levels without plans. Create the missing plans with View → Plan Views → Floor Plan, and pick the levels from the list.
- Building Story. Untick it for levels that are not floors, such as a parapet or a top of foundation. They then stay out of the lists where Revit asks for a storey.
- Elevation Base in the level type: Project Base Point shows heights from the project zero, Survey Point from the survey (sea level) datum. Use two level types if your sheets need both.
03Grids
Grids are drawn in a plan: Architecture → Datum → Grid. Revit numbers them in sequence from the last one you named, so name the first grid 1 or A and the rest follow. A grid can be straight, an arc, or multi-segment, for a building that bends. The grid head, round, diamond or a bare number, is set by the grid type.
04Reference planes
Reference planes are the datums you place yourself, in any view: Architecture → Work Plane → Ref Plane. In a project they are used to set a work plane (to model on a sloped face, or to place a face-based family), and as guides that walls and lines can be aligned and locked to. Give a reference plane a Name in Properties: only named planes can be picked by name in Set Work Plane. In families, reference planes carry the parameters, which is why a family is only as good as its reference planes.
053D and 2D extents: why a datum is missing in a view
A level, grid or named reference plane appears in every view it crosses. Its 3D extent is the real length of the plane in the model. Its 2D extent is only how it is drawn in one view. Select a grid and click the small 3D label at its end to switch that end between the two.
- Grid missing in a plan: its 3D extent stops below the cut plane of that level. Drag the 3D end in a section or elevation above the top level.
- Level missing in a section: the level line does not reach across the section line in plan. Drag its 3D end past it.
- Changed one view and want the rest to match: select the datums, then Modify → Propagate Extents and pick the parallel views.
- Undo a mess of 2D ends: right-click the datum and use Maximize 3D Extents.
06Scope boxes for datums
On a real project, dragging the ends of every grid in every view does not scale. Draw one scope box around the building (View → Create → Scope Box), select all grids and levels, and set their Scope Box parameter to it. Their 3D extents then follow the box, and resizing the box resizes all of them at once. Use one box per wing on large sites, and assign the same box to the plan views so they crop alike.
07Datums from a linked model
In a team, the architect usually owns the levels and grids, and the structural and MEP models copy them. Use Collaborate → Copy/Monitor → Select Link, pick the levels and grids from the linked model, and Revit copies them into your file and warns you when the architect moves one. Do not draw them twice by hand: two sets of grids that differ by 2 mm are a clash in every coordination meeting.
Rule of thumb: set out the levels and grids first, lock them with Pin, and only then start walls. Moving a datum before the model is built on it is easy; moving it afterwards is not.
Datums drawn the same on every sheet
In the DATUM Revit template, the level marks, grid heads and section heads are drawn as one family of symbols, so a plan, a section and an elevation read as one set. The template comes with the levels of a typical building already in place, from the basement to the roof, each with its floor plan and sheet.
- Level marks in four versions, with the name above the level and the height below.
- Grid heads round, diamond or bare, and section heads drawn to match.
- Plans, sections and elevations on A4–A0 sheets, ready from the first day of a project.
DATUM for RevitThe Revit architecture templateLevels, grids, title blocks, tags, schedules and views on one standard.See the template →
Questions
What are datum elements in Revit?
Levels, grids and reference planes. They are the planes the model is set out from: walls and floors are attached to levels, columns sit on grids, and reference planes give you work planes to draw on. In the ribbon, levels and grids are on the Datum panel of the Architecture and Structure tabs.
Why is my grid not showing in a view?
Most often its 3D extent does not reach the view: the grid line stops below or above the plan’s cut plane, or outside the section. Drag its 3D end so it crosses the view, use Maximize 3D Extents, or give all grids one scope box. Also check Visibility/Graphics and that the grid is not hidden in the view.
Why does my level have no floor plan?
A level made with Copy or Array is created without a plan view, and its head shows in black instead of blue. Create the plan with View → Plan Views → Floor Plan and pick the level from the list.