Modeling Structural Elements

BIM for Architecture, Engineering, and Construction Curriculum


Linking and Architectural Model and Copying Shared Elements

What are the advantages and disadvantages of linking to a Revit model versus sharing a single project file?

Through linking, you maintain manageable file sizes and help protect against inadvertent changes being made by team members to our designs.

Sharing a single file for smaller projects and within smaller collocated teams can cut down on the coordination work of using separate linked files. Coordination, instead, can be achieved by using worksets, which guards against unwanted edits to your portion of the design.

How does linking to models affect the performance of a host model?

As the file size increases, the performance of the host model may diminish.

Is the information displayed in a linked model refreshed automatically?

When you open a host model, the linked models are refreshed. Otherwise, we have to reload links from the Manage Links dialog box.

Why does the Copy\/Monitor tool limit the types of elements that can be copied and monitored? What do these elements have in common?

It limits you to copying the elements that are essential for coordination between the different models. It limits these types so that you do not unnecessarily copy in elements that will not be needed and, thus, burden the model and degrade performance.

What are the advantages and disadvantages of copying shared building elements as generic types versus copying the original types?

Copying elements as generic types makes it easier to identify the copied versions versus the ones that you have changed to accurate types in your modeling process.

Modeling Concrete Columns, Beams, and Floor Slabs

Can you rotate columns as you place them?

Yes; by pressing the space bar, you rotate through the available options.

What are the advantages and disadvantages of placing a column by specifying its depth versus specifying its height?

It will change the level with which the column is associated. 

What are the advantages and disadvantages of placing columns in 3D views?

3D views can be used for placing columns at grid locations or when snapping to other points. But plan view should be used when accurate placement is required and snap points are not available. One advantage of placing elements in 3D view is that you can immediately see and verify the results.

Which 2D view is best for placing beams at the top of the level 1 columns?

A reflected ceiling plan view that allows you to see the placement plane from below.

Modeling Wood Columns, Beams, and Floors

What is the difference between the nominal dimensions for wooden elements and the actual dimensions? Is it the same for all sizes?

The nominal dimensions of a piece of lumber, such as 2x4 or 2x6, are always somewhat larger than the actual, or dressed, dimensions.

The nominal dimension is the next highest integer value from the dimension specified. For example, 1.5 x 3.5 inch (38 x 89 mm) members are referred to as 2x4s.


Why is it better to align the outside faces of the wood columns to the edge of the floor versus leaving them centered on the grid intersections?

Because the face of the columns on all levels should be flush with the exterior face of the wall, so that the columns will align with the wall framing and not protrude into the finished space.

Why are beams placed in one direction and a beam system of smaller joist elements placed in the other direction?

The beam system of joists is supported by the beams running in the orthogonal direction at their ends. For that reason, the beams must be bigger in order to carry the cumulative loads from the joists.

Why is the elevation of the beam start and end offsets and the beam systems lowered to match the thickness of the structural floor?

The beams are dropped in order to represent the actual construction conditions. Wood beams are typically located below and support the structural floor, but do not intersect with it.

Modeling Structural Walls and Foundations

What are the key differences between structural walls and basic wall types?

Structural walls have extra properties, such as its structural type (shear, bearing, and so on) and others that enable analytical modeling. 

What determines whether a wall requires a wall foundation?

Walls that carry loads from above require wall foundations in order to transfer those loads to the soil. Interior partition walls and nonbearing walls do not require wall foundations. 

Are isolated foundations needed to support columns that are embedded in retaining walls?

Typically not, since those retaining walls will have wall foundations.

Why are isolated foundations needed under the interior columns? Would the slab foundation not provide enough support?

The interior columns are transmitting point loads that are the accumulated from the loads above and, thus, require an isolated foundation to transfer the loads and avoid punching through slab.