Structures in Revit (I)

Modelling Datums

First step when starting a new structure model is to set Grids, Levels and Reference Planes, which is known as Datum. That’s mandatory!

Grids, Levels, and Reference Planes are the primary control data used in Revit. Not only for traditional documentation, but Revit uses these data to control movement and behavior of various elements, especially structural elements.

Grids

Grids must be carefully placed, when creating a Grid do not use a inserted dwg file and “pick” a line in it (in fact never do that creating anything): Grids lose parallelism or orthogonality and whole thing becomes a headache. Just use the dwg file (if exists) as a reference and place grids using dimensions. Once Grids are settled pin them to make sure they’re not going to move “by mistake”. Remember you can also model a grid as an arc or also as a multi-segment line.

Notice Grids can be scheduled, so it’s easy to check right naming and right Type. Moreover, there are some interesting adds to improve managament of Datums. I highly recommend when collaborating different disciplines in the same model or when having different buildings in the same model to distinguish different groups of Grids using Types or adding a new parameter applied to them, it helps a lot to keep control. For the same purpose, do not hesitate in moving Grids into different worksets, order is the base of a successful model!

Levels

Levels are always horizontal and straight. As Grids they are used to control location of various elements, all the stuff about order in Grids: schedules, types, worksets… applies also here.

Reference Planes

Reference Planes maybe are little used but that’s because unfamiliarity and not because of being little valuable….

Where you need a Datum, but do not want a plotted Grid or Level use a Reference Plan. When may occur that? For example when you model sloped roofs, offset secondary braces, symmetria planes, shaft openings… Reference Planes are very useful cutting columns and beams (see Post: Cut beams and columns in Revit) and you can also attach a wall to them.

Reference Planes are also very useful as Work Planes:

Work Planes

When modeling, normally an active Work Plane is required. In a plan view, the work plane is usually set to the current level associated with the view. As well as Levels, Work Planes can be defined as: Reference Planes, Grids or a surface of another object. After you add Reference Planes to your project and you name them (yes, Reference Planes can (must) be named), they can be set and seen from the Work Plane panel (unnamed Reference Planes are not). This will allow you to work with respect to the desired work plane.

Let’s have a look to a pair of pictures showing previous concepts:

In picture above we can see Grids in blue, Levels in green and Reference Planes in red. In the floating windows of next figure you can see how the “Slope 1” Reference Plane is selected as current Work Plane among all possible options. In the 3D view with Show Work Plane option on, the “Slope 1” Reference Plane is shown in blue, that really helps when working with not ortoghonal planes.

So, before starting to model columns, walls, beams… think about the model context and traduce it into Datums, that is: Grids, Levels and Reference Planes. You will need them to correctly create, place and modify your elements!