Datasheet

WHAT TO EXPECT FROM BIM
9
Forget About Layers and X-References
If you’ve already made the jump into Revit, then this will already be obvious: Rather than user-
defined layers, you use an intelligent architectural classification system to manage visibility, graphics,
and selection. This may seem stringent at first, but once you get the hang of it, you’ll see the bene-
fits. Because a building model is an assembly of meaningful, to-be-built objects, you control the vis-
ibility and graphics of those objects using a rational list of well-understood categories. This also
makes it easy to select similar elements and edit them. Figure 1.8 shows the list of classifications
that manage visibility. You can’t add to or alter this list, which means every project enjoys the same
level of visual predictability. And of course, with an integrated model, you don’t need to worry
about referencing other drawings to keep the drawings up to date and in sync.
Figure 1.8
The Visibility/
Graphics Overrides
dialog expresses the
entire range of ele-
ments used in Revit.
BIM Is More Than a Technology: It’s a Change in Process
One of the powers of Revit is the ability to work in a single-file environment where the design and
documentation of the building happens on a holistic model. This can be a disadvantage if it isn’t
taken seriously. Users who are quick to make changes without thinking about how such changes
will ripple through the model can cause unintended problems. Revit is a parametric modeler—it
creates relationships between building elements to streamline the design process. For example,
deleting a roof underlay in a view doesn’t just delete the roof in that view—it deletes it everywhere
in the model. You need to think before you delete that wall or ignore that warning message!
Be prepared to work in much tighter, collaborative teams. As soon as you enter the BIM multi-
user world, you absolutely need to be communicating with your team all the time. The changes that
you make in the model will impact the whole model and other people’s work. We think this is a
great—perhaps unintended—consequence of moving into a model-based design paradigm.
Anticipate that tasks will take different amounts of time when compared to a CAD production
environment. You’ll perform tasks in Revit that you never had in CAD; and, conversely, some CAD
tasks that took weeks (such as chamfering and trimming thousands of lines to draw walls properly
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