Walk-Through Study

This study of a current project was created at the client's request, to aid in visualizing an important area of the building, which was not addressed in the SketchUp Design Development model.





An in-place massing model was created using CAD backgrounds.

Walls were added in the area of interest using 'Wall by Face'.

Doors, windows, decks, and railings - salvaged from other projects - were added in the focus area only.

Topography placed in the courtyard area, with various materials placed by sub-region, using a landscape background as the template.

A 'fly-in' animation sequence was created by manipulating camera path key frames in a section view.

A 'fly around' animation sequence was created using 3D lines as a template for the path. Key frames were added to smooth out the camera motion.

The two animation sequences were aligned by placing the views on a sheet in wire-frame mode. All camera adjustments were made using the 'Look' feature on the Revit Steering Wheel. The two sequences were then combined with titles and effects using Windows Movie Maker.

Site Specific Design Options

Adopting BIM to replace CAD is more than just learning this new tool. The tool is intended to do a slightly different job, and so it may not fit into your hands in just the same way.

In residential projects with multiple buildings, whether single or multi-family, one of the expediencies forced by CAD is that every instance and variation of every building is not fully documented. There is a ripple effect throughout the drawings. Changes must be followed through. And this is where the weakness of CAD becomes too obvious to ignore. It is extremely inefficient when it comes to the minor adjustments and fine tuning of the drawings. And so we do not do it. Because of CAD.

The logic is that since we are not responsible for the vertical placement of buildings on a site – that is the civil engineer’s task – we cannot possibly be asked to keep up with such changes. Instead we frequently refer to someone else's drawings, and it's up to the builder to put it all together in the field.

In the Playa Vista project, the documentation for all six buildings on the site is generated from a single model. The efficiency of using groups with Design Options is described in the previous post.

Building sites are never flat. In residential building, the threshold of the garage is always at least six inches below the finish floor level. The minimum standard is a four inch step and two inches of slope (one percent). 


In single family, the step-down may be increased to adapt the building to a sloping site. With larger buildings, in addition to the garage step-down, sometimes the entire floor slab must be offset, or even the entire building. Although these decisions are not within our scope, we are required to depict this information on our drawings.

Experimentally, for Playa Vista we added six new options to the three original "prototypical" ones which are depicted in the construction drawings. It was very easy to divide the slab, slope the garage floors, and add wall curbs where required.

The accurate depiction of each variation is important because of three stairs which may require adjustment, where headroom, landing depth and handrail extensions clearances are critical. Additionally, detailing around the base of the building must be coordinated where the lower slab offset may be as much as twenty-one inches below the main floor.

Quick QAT

A quick tip to speed up Revit work flow is to move the Quick Access Toolbar below the menu ribbon.

It should probably be there by default. I've noticed that many users overlook it at the top. To move it simply select the option at the bottom of the drop-down.

The Out-of-the-Box commands are as shown.

Add almost any command to the QAT by right-clicking... 

My personal favorite is to place the Type Selector drop-down on the QAT. Because the interface is context sensitive, alternatives to the object currently selected are shown immediately above the work space.

For the Playa Vista project described in the previous post, which was heavily dependent on Design options, placing the 'Pick to Edit' tool on the QAT was an incredible time saver when working among the various options in the model.

Design Options & Groups

I am working with two teammates on a project for Brookfield Homes, the unequivocal leader among home builders who have embraced Building Information Modeling.

My colleague Louis Navarette is responsible for the development of Brookfield’s BIM Guidelines, families and template files which are provided to the architects and engineers who serve them. While the performance guidelines are very strict, specific methods are at the discretion of each designer.

Exterior Styles

The Playa Vista project consists of six four-story buildings - three dwelling levels over a garage level. There are two different building configurations. Four of the buildings contain six dwelling units; there are also two "tri-plex" buildings, which are derived by removing three smaller units from the larger building, while maintaining the main lobby and both exit stairs.

There are also two separate exterior treatments – A & B. Some exterior elements are shared by the two larger buildings only (6A & 6B). Other elements are shared between the larger and smaller buildings of the same style (3A & 6A). It was apparent from the beginning of the project that Design Options should be employed.

Design Options in Revit is intended for the depiction of several alternates or variations of a base model. The Design Options interface manages the display of the model based on the selected option. Only elements that change are placed into the option. Objects that occur in all three buildings are not duplicated – they reside in the “main model”.

Exterior Groups

During the course of our work, it became apparent that, for the most efficient modeling process, elements that were shared by two of the three options could be placed in Revit groups. When the group is edited, changes are automatically propagated to both versions, eliminating duplicate effort while insuring that design continuity is maintained.

Interior Groups

While there are three exterior options, the interior of buildings 6A & 6B are identical. For further efficiency, we decided to place the building's interior components (partitions, doors, plumbing fixtures, etc.) into a separate design option. Interior components that are identical from floor to floor are also grouped so that interior changes are also automatically propagated throughout all floors and styles.

When Design Options are activated, an additional tab is displayed in the Visibility/Graphic Overrides dialog. When set to Automatic, the model view displays the active option. For ease of editing, the template provided by Brookfield contains Working Views that may be pre-set to the desired combination of options.

There are two built-in filters to aid working with Design Options. When 'Main Model' is selected, individual elements within an option may be modified by unchecking the box labeled 'Exclude Options'. 

When a Design Option is active, elements in the main model may be edited by unchecking the box labeled 'Active Only'.

With a team of three on the project, the work flow was uncomplicated. Typically it was one person on the interior, one on the exterior, and one in a separate Composite Document file. Overall I am very satisfied with the methodology that evolved for this project, and intend to use it as a prototype for the next one.

KMN

I work for one of the most prestigious and stable architectural firms in Orange County. I am the staff Revit guru, a position that allows great freedom and flexibility in determining how I approach my work. Currently, I am working with two other team members on a multi-family housing project for Brookfield Homes, a leader among home builders who have embraced Building Information Modeling.

We have two or three weeks remaining before the first CD submittal, with a lot of annotation and detailing still to to do. This is our first Revit 2013 job. Our client has expressed a desire to move to the built in keynoting system; previously we used generic annotations and note blocks. We are using Steve Faust's Keynote Manager on a 30-day trail, while waiting for approval on a site license.

In spite of all these conditions, when my project manager approached me yesterday with a request to use "dumb keynotes" as in CAD, I actually agreed!  I was immersed in another aspect of the project, and had not really considered the problem. I even created an instance-based symbol to be used in conjunction with blocks of text. Near the end of the day, when I paused to consider my accomplishments, I realized to what I had agreed. My first reaction was "KMN"

As with many firms in the housing industry, most of the work here is still being done in CAD. I recently I made a presentation to the staff here, extolling the benefits of BIM. which was entitled, "It's Not Rocket Surgery".

I quickly went to work, importing some notes from previous projects into the new keynote text file database. This morning I showed it to my PM, who is now on board. When he said, "I didn't know where to start" I realized I had failed to give the proper level of support for a new process.

Reality & Illusion

In the West (and I assume throughout the U.S. and elsewhere), where wood frame construction is dominant, these standards apply:

Standard length for 9 foot (nominal) studs is 104 5/8" or 8'-8 5/8". With top and bottom plates added, the standard plate height should be 109 1/8" or 9'-1 1/8". This allows for approximately a 9 foot clear interior ceiling height, depending on the finish.

For engineered joists, the actual size of the TJI-12 is 11 7/8", while the TJI-14 is actually 14".

Using these values, the top of 3/4" plywood sheeting will be 10'-1 3/4" for the TJI-12 system; and 10'-3 7/8" for the TJI-14 system. Roof plate heights for the two systems and 19'-2 7/8" and 19'-5" respectively.

In CAD, where accuracy is often pushed aside for expediency (because it's so inefficient?) these values have been "leveled off" to 9'-1", 10'-2", and 19'-3".

Also in CAD, reference values from finish floor are rarely given. The plate to sub-floor dimension is also excluded. The logic (?) being that at the start of the job, the floor assembly depth is unknown, and CAD must be protected from the demand for changes, where it is extremely inefficient.

When modeling with Revit, the best practice is to use actual values whenever they are known. There are no "unknowns" in a Revit model. The model is a record of all the information gathered about the building being designed. What better place to record those decisions accurately than in a Building Information Model?

Practitioners who wish to see no "differences" between CAD and Revit may set the dimension tolerance "to the nearest inch" and exclude the values from the level annotations.

There is no substitute for accuracy. 
When using Revit, do not attempt to substitute an illusion for reality.

Are We Men (and Women) or Are We Monks?

From Wikipedia:

The at sign or Astricks @ is also commonly called the at symbol or commercial at in English—and less commonly a wide range of other terms. The fact that there is no single word in English for the symbol has prompted some writers to use the French arobase or Spanish arroba—or to coin new words such as asperand, ampersat—but none of these have achieved wide currency.

Originally an accounting and commercial invoice abbreviation meaning "at the rate of" (e.g. 7 widgets @ $2 = $14), in recent years, its meaning has grown to include the sense of being "located at" or "directed at", especially in email addresses and social media like Facebook and Twitter.

Medieval monks abbreviated the Latin word ad (at, toward, by, about) next to a numeral. One reason for this abbreviation was that it saved space and ink. Since thousands of pages of Bible documents were copied onto expensive papyrus or hides, and the words at, toward, by and about repeated millions of times throughout the ages, a considerable amount of resources could be spared this way. 

In architectural drafting (hand drafting) many were taught to use this symbol as shorthand for "spacing":

• 1/2" A.B. @ 32" o.c.
• 11 Risers @ 7 1/2"

Somewhere along the timeline, after the transition to CAD, practitioners began to use the symbol where its meaning was not spacing but location; for example - Building Section @ Lobby.

In hand drafting there is some defense for this practice. It saved time and graphite - just like in medieval times!

But we are now in the 21st century!

It takes the same amount of time or less to type the letters "AT" than to hold the shift key while pressing "@". Certainly not more. Nothing is being saved.

Of these examples, which looks better? Which is easiest to read?

• WINDOW SILL @ FIBER CEMENT SIDING
• WINDOW SILL AT FIBER CEMENT SIDING
• WINDOW SILL at FIBER CEMENT SIDING
• Window Sill at Fiber Cement Siding**

One of the benefits of implementing Revit/BIM (getting rid of CAD) is that it provides an opportunity to re-think many of the practices that have been erroneously carried forward into this modern age. This is one.

**Stay tuned for my indictment of "ALL CAPS" text.