My Second Revit Project - Part 1

So today I decided to start a series of posts about the second Revit project that I was involved in from Design all the way into Construction, which is the phase we’re currently in. The steel is almost all erected and stud framing and roof carpentry (wood blocking) is in progress. That is, when it’s not raining!

This is a challenging project and I can’t wait to see the end result. But first some history: the original school building was designed by renowned firm CRS in the 1950s. The almost sixty year old campus has seen numerous additions and renovations over the years and it was time to give the “old lady” a nice, well deserved face lift. The main issues that we were asked to address were security, campus expansion and renovation and the installation of a new heating and cooling system to service the new addition and most of the existing buildings. The original campus was typical regional architecture: wide overhangs with very low roofs and narrow, “finger” plan buildings with open breezeways.

Back in those days, there was no air conditioning, and natural ventilation was the only means of cooling. Well, this is the Houston area we’re talking about. I don’t honestly know how they lived without A/C!

Adding insulation and using high performance, high impact glazing was key and the final solution had to “fit”. The goal was to make this “new” facility look like it was all built at the same time, and believe me….it was and still is a huge challenge! We wanted to keep as much of the original buildings and structures as possible for budgetary reasons and also to respect the original CRS buildings. You can see the existing structure in red in the pictures below with new structure nestled into it:

The only available space for expansion was the area between the existing “finger” buildings. We had to give up the “courtyards” to bridge this area with a new building, which is higher so that it could accommodate clerestory windows to bring in natural light, to house mechanical mezzanines and to tie in with the slope of the existing roofs. We re-used many of the existing sloping fascia details to tie the new with the old.

This was the first project where I had to learn all there is to know about Phasing in Revit. We pushed the boundaries and learned a lot. We started by modeling the existing building and structures that we were going to tie into. This helped us visualize those complex situations where new structure was to be nestled into the existing. It also helped us see what our massing options were based on seeing exactly which parts of the existing structures we could demolish. And all this while designing the new addition and taking construction decisions at the same time.

The hardest challenge in Revit was to figure out how to demolish parts of elements, such as roofs, beams and walls. I will discuss some of these techniques in future posts and will continue to write about the progress of this and other projects.

My Second Revit Project - Part 1

Floors and Color Schemes

Prior to Revit Architecture (RAC) 2008, when one added a Color Scheme to a floor plan view (back then it was termed as a Color Fill), if Floor visibility was turned on, Revit would issue a warning and turn it off for you so the colors would display correctly. This meant that in some cases, the “correctness” of the plan representation would be compromised.

To illustrate, imagine you have a colored floor plan on Level 2. There is an opening in the floor slab and a stair goes down through it. The last few steps leading to the first floor are covered by the slab above (the opening doesn’t go the entire length of the stairs).

Since Revit wanted you to turn floor visibility off, you would see the entire stair run, which is incorrect. The last few steps (shown dashed in the image above) are supposed to be hidden, so the workaround for this situation was to hide the last few steps by placing a filled region with the same solid color fill as your floor plan space.

In RAC 2008, we now have “Color Schemes” and Revit no longer turns off Floor visibility. But hold on…don’t get too excited! Unfortunately, there is a bug, which is known by Autodesk (and hopefully we’ll see a fix sometime in a future release).

Even though the floor is visible, it is in some state of “transparency”. The last few steps show through the slab. Notice also how the continuous wall on the level below shows through too, indicating the floor has become transparent. Notice how the grey wall color shows through the surface pattern of the slab, which is another indicator that the slab has become transparent. Surface patterns seem to display just fine but if a color was assigned to the floor material and the view was set to Shaded, this color is not displayed (compare to the first image).

The above image shows a color scheme set with the option “foreground”. If the option “background” was enabled, the floor area at the steps would not be colored correctly, as shown in the image below. So how do we fix it you might ask? The linework tool? No, actually that doesn’t work on this portion of ths stairs. Somehow it seems that Revit knows this shouldn’t be displayed and the linework tool does not “see” these lines.

So the same workaround as in previous versions of Revit still applies….head for the filled region! (the floor surface pattern was left visible so you can see where the filled region is located).

Floors and Color Schemes

Detail and Model lines mayhem

I remember my initial perceptions when I started working in Revit and used to think of Detail lines as Annotation elements, since they are view specific. But Detail lines are in fact used also to represent real Model elements, hence their currently implemented state.

Their line weight is controlled in the same way as modeling objects. You assign a line weight between 1 and 16 to a Line Style and it will print according to the combination of thickness and scale as specified in the Line Weights dialog. The confusing thing for a lot of users is that the same line style used for a Detail line is the same as that used for a Model line. To make it worse, we cannot control the visibility of Detail Lines independently of Model Lines (go the the Visibility/Graphics Dialog to confirm this). And here's another one....the filter tool (the little icon on the options bar) doesn't see a difference either! Yet we all know they're not the same.

So a Detail Line is not a Detail Item and it is representing a part of a model, yet a Model Line is not easy to tell apart from a Detail Line and on top of that, it has no Assembly Code parameter, so is it really a Model object? And for both these unique line objects, we cannot use filters to override their visibility. Sounds like the perfect recipe for disaster.

In essence, there is not much difference between the two: Detail lines are just view specific and Model lines show up everywhere, including 3D views. So how do you tell them apart?

There is a little known parameter in the View Properties dialog called Display Model under the Graphics category. You can select "Normal" (the default), "As underlay" or "Do not display". When you select the "Do not display" option, every model element in a view disappears, or so it seems. Upon closer inspection, you'll notice Detail Lines stay visible. "But Dave, you're confusing me....didn't you say that Detail Lines are controlled by the Lines category in the Model Tab of V/G?! So you're saying they're not Model elements after all?". Well, uhm....hey, I'm just the messenger here!

So if you want to figure out what kind of line you used, set the Model to display "As Underlay" and your Model Lines will be halftoned. Now you can tell Detail Lines and Model Lines apart. This comes in handy when you used the wrong object and want to fix your input. There is really no easy way to turn a Model Line into a Detail Line or vice versa. Keep in mind that by setting the model to not display, you can window-select your Detail Lines easily if you want to delete them. Alternatively, if you mean to keep Detail Lines and delete Model Lines, you can do the same thing but this time, temporarily hide the Detail Lines. Now turn the model visibility to Normal, window-select your objects, visit the filter to make sure you only selected Line objects, and then delete and reset your temporarily hidden objects. Keep in mind that you'll need to use a combination of all these tools to correct your problem, together with a nice dose of patience.

Detail and Model lines mayhem

My first post.

Hi all and welcome!

I have been pondering whether to start a blog for quite some time now...."will you keep up with it?"......"do you have enough time?"; I think you can relate to these kind of questions that linger in your head, but I'll never know the answer unless I try, right? And what better way to blog than about Revit, BIM and Architecture?

So I spent some time thinking of a name and decided to directly ask you, the reader...."Do You Revit?". Because I do and I would like to share some tips, techniques, experiences and examples of work done in Revit. I believe that exploring the exterior and interior spaces in a three-dimensional digital environment helps us produce better buildings. But it doesn't stop there, and through my posts, I would like to extend the discourse about BIM and how it is impacting our industry. What issues are firms and BIM Managers faced with when implementing Revit in a multi-office, multi-disciplinary firm? How is productivity impacted during the beginning stages of implementation? What are some of the pitfalls to avoid?

From time to time, I would like to also post about current project work, whether in construction or on the boards. The blog graphic above shows images of my first Revit project (lower image) and the current project I'm following in the field (top image), both projects that I'm extremely proud to have played a significant part in. January marks the end of my second year using Revit and I'm very excited to have taken the plunge. I hope to keep you interested in visiting my virtual corner in the world frequently, and that you learn as much as I have learned by following other outstanding blogs dealing with this subject.

My first post.