Expertise

Structures in Revit (IIb)

Modelling Walls

If you are a follower of previous Posts, you will know that before starting modelling walls, you should have entered all project Datums ( Grids, Levels and Reference Planes) and modeled Structural Columns.

Already done? Ok, then let’s build Walls

System Family

Like other basic elements, walls are a system family. Walls are composed by several layers of different material and thickness. When we talk about a supporting wall, wall must have a single layered structure. See figure below: supporting layer have Structure [1] Function and is located within the limits of the core.

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Placing Walls

In horizontal plane, walls have to be placed against a Grid, a Reference Plane or another element with offset dimensions. In vertical plane, walls are placed from a Base Constraint (a Level) to a Top Constraint (other or same Level). Base and Top Offset parameters allow an offset to those Levels. All four parameters must be consistent, I mean: if a wall is a wall in Level 3, Base Constraint can’t be Level 1 plus a Base Offset. Or worse: a wall with nobody knows which Base and Top Constraints but with its profile edited to fit into right Levels… Best way to check that is a schedule! See:

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Walls can be attached in his top or base to another element. That other element can be a Floor, a Roof, a Stair, a Reference Plane… Notice they can be attached to a sloped roof, that way we avoid the other option that is the continuous edition of profile as design changes.

Function Parameter

When you expand the Function Parameter, you can see that there are a number of functions available: Interior, Exterior, Foundation, Retaining, Soffit and Core-Shaft. These can be used for filtering, scheduling and layer control when exporting to CAD. In addition, when you export analytical surfaces to gbXML, the Function type parameter affects its performance. My advice is to use Function parameter to add complementary data to filter o schedule… if an Energy Analysis is foreseen then make a more accurate choice.

Location Line

When setting the location line you have to think in the limit of the wall you don’t want to be moved. Maybe it can be the Wall Centerline if wall is located under a beam system where axis is fixed. Maybe it is Core Face Exterior if wall is aligned to a structural column surface or a slab. Location line will persist although width or structure is modified. Previous examples are illustrated below:

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Structural or not Structural

Now let’s see the difference between selecting Structural Parameter or not: Defining a wall as not Structural means, logically, other structural parameters are not available.

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Defining a wall as Structural makes available Rebar Cover properties or Structural Usage. We can also select Enable Analytical Model, which I highly don’t recommend if our model is not going to be used as an Analytical Model inside Revit or using other structural engineering software.

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Wall Joins

When placing adjacents elements in a structural model such as walls or structural columns, if they have same material, elements will automatically be joined. However if you want a line to appear between them you always can “Unjoin Geometry” or, in the case of two walls, “Disallow Join”. Also remember you can use the “Switch Join Order” to change the order in which elements join with one another. All that tools are in Modify/Walls  / Geometry / Join.

Little tips

  • Use Copy to Clipboard and Paste Aligned to Selected Levels when you want to copy the walls modeled in one Level to other Levels (you can select more than one at a time).
  • Use tab key to select a chain of walls, that’s very useful.

See you next Post!