Datum Elements

When you start a new project, there are often some set up actions that you need to perform. Chief among them is establishing the datum elements that frame the project and structure its elements. Revit has three datum elements:

• Levels—represent the floor levels in your building. They run parallel to the ground and are given a height in your project. You will typically have a level for each storey of your building. You will also see levels for grade, top of foundation, top of steel, parapet, etc. Any meaningful vertical location in your project can be marked by a level. Objects in your model will in turn be associated to one of your levels.
• Grids—represent the location of the building’s structural elements. The most common application of these it to use them to locate the building’s columns. Grids run vertically through the building (perpendicular to levels) but can run at any angle in plan. If your building is using columns, you will typically place a series of grids to help locate and manage them.

Reference Planes—are like guide lines. You can use a reference plane to mark any important or meaningful datum location in your project. They can run horizontally or vertically or at any angle. Use them in situations that would not be practical for levels and grids.