Building Envelope

BIM for Architecture, Engineering, and Construction Curriculum


Modeling Wall Types, Structures, and Design Features

How is the total thickness of a wall type computed?

The total wall thickness is determined by adding thickness to each of the different layers that make up the wall assembly.

How can changing a wall’s type affect the clear space between adjacent walls?

Changing a wall’s type typically changes the wall thickness, and this can change the space available between adjacent walls. Where the thickness will be added depends on the location line setting of the wall.

In a typical residence, what locations are most critically affected by the wall thickness?

Narrow hallways, closets, bathrooms, or anywhere where the space provided is close to the minimum clearances required.

Adding Doors, Windows, and Wall Openings

Do the doors and windows move with the walls?

{/p} Doors and windows will automatically move when their hosting wall moves.

They can also move within a wall if constraints have been set up that link their position to other objects (for example, intersecting walls or nearby doors or windows).

Windows do not change location if the wall length or height is resized.

Do doors and windows automatically adapt to the thickness of the host wall?

Yes. The elements (frames, jambs, sills, and so forth) of the door and window components typically resize themselves based on the thickness of the hosting wall.

What happens if the boundary of the door or window exceeds the extents of the wall?

Generally, Revit will allow you to place doors and windows as long as the placement point!typically at the center of the window!is within a wall.

If a wall is a resized such that the placement point falls outside the new boundary of the wall, Revit will report an error saying that it cannot cut the wall opening and will remove the window.

Can you place a door at a height above or below the associated floor level?

Most doors offer a sill height instance property that enables you to specify an offset above or below a floor level.

Creating Roof Shapes

What would be the method for creating a barrel vault roof?

{/p} Barrel vaults are best modeled using a roof by extrusion. The profile can be sketched as an arc or semicircle, and then extruded to form the length of the roof.

How about a dome?

Dome roofs are more difficult to create. One strategy is to create an in-place component that revolves an arc segment around a vertical axis. Unlike roof by extrusion, the profile to be revolved must be a closed loop indicating the thickness of the roof.

How would you model a sloping roof surface surrounding a lower flat roof—a strategy often used to conceal utilities and mechanical equipment?

This sloping roof form could be generated using roof by footprint, specifying two boundaries—the outer and inner edges of the roof. The outer boundary is typically specified as slope-defining, whereas the inner boundary is not, to create roof planes that slope up from the exterior.

What can you do if Revit reports that it cannot create a roof by footprint using the boundary sketched?

When Revit reports that it cannot create the roof by footprint, this indicates that geometry specified in the sketch and slope configuration is physically impossible to create. First create a simpler shape (with fewer slope-defining edges and equal eave widths) and then iteratively edit the boundary sketch to add in complexity and details.