Revit is a powerful Building Information Modeling (BIM) program widely used by architects, engineers, and other design professionals to create intelligent, data-rich models of buildings, structures, and their systems.
The following is a transcript of a video on Revit by VDCI instructor, Mike Wilson.
A common question that I get from students when they're starting to learn Revit is just the basic question of "What is Revit?" And so if you're one of those people who are moving from CAD or SketchUp or another program, you might have some preconceptions on what this software is, and so I just want to cover a few things here. First off, Revit is not a drawing program. It's much more than that: it's a database. And so you can see here I've got a handful of views that represent the model, and they're all in different forms. And so the first one, we have our floor plan, which, if we just look at that for a minute by itself, it just looks like a 2D plan. But what we don't realize is that the impacts that I can make here are going to have an effect on all the other views. So, for instance, this section view here, which is this guy, if you look at -- and I'll go back to that tiled windows -- uh, but if I select this wall, it's actually going to show as selected in blue within our floor plan. And you can see it selected in our 3D view here as well. And that's because when we look at something like a floor plan, what we're looking at is just a slice of that 3D model, or as a lot of people like to refer to it, a database of all of the data within the model.
The Eight Core Principles of Revit
And so we're going to look at eight core principles that make up a Revit model and essentially make up what Revit is.
Learn Revit
- Nationally accredited
- Create your own portfolio
- Free student software
- Learn at your convenience
- Authorized Autodesk training center
Concept 1: Parametric Objects
And so the first one is going to be parametric objects. And so the best way to show that is with a door. So a door has parameters. So you can see this door is single flush 36 x 84. And so this door is made up by a family, a type, and an instance. And we have parameters that make up the instance and the type. And so here in our type properties, you can see I've got different parameters that can be parametric. So let's say I were to change this door from 3 feet to 2 foot 6, then all of the doors under this 36 x 84 umbrella are going to change to 2 foot 6. So you can see door 104 and 103 are the same type. And so when I make that change, these all got smaller to 2 foot 6, whether I wanted that to happen or not. And so what that does is it allows me to make changes to the doors all the way across the model, or I could do something as simple as adjusting the sill height where its level is base, or maybe just the mark here, which is this tag that you see added individual basis, door-per-door.
Concept 2: Bidirectional Associativity
Concept two is what we call bidirectional associativity, and that's just a fancy way of saying if I change something in a location once, it's going to change everywhere. So we're using door 104 as an example in our first exhibit here. And if I look at this quick door schedule that I put together, you can see we have door 104 here. And if I change this from 104 to 199, for instance, it's changed here in the schedule, and it's also changed here within the plan. And so if I make that change back to 104, I go back to the schedule, and you can see that 104 is back to being door 104. And before you freak out, yes, we can definitely sort this schedule by mark so that all of these doors go into order. It's just like working in Excel, and it's a pretty simple process to go through. And so what I like about this is there's no forgetting to update the drawing because a lot of these things, the computer takes care of for us.
Concept 3: Embedded Relationships
Concept three is embedded relationships. And so this occurs in a couple of different ways. So, one of them is going to be elements know how they're supposed to interact with each other. So, if I were to add another door into this telecom room here, the wall knows that it needs to be cut by the door. And so, when I place these doors in here, they know to cut out the wall. So, that's one element of that embedded relationship. Just going to go ahead and delete those. The other one is we can actually tell elements to stay attached to each other. So you can see here this wall for the shaft wall for the elevator, or maybe these ones for the rated walls around the machine room. If I were to say attach this wall, the top of it to the roof above, there's now a relationship between those two elements, and so if this roof were to go up, say 3 feet, those walls are going to go with it, and I don't have to worry about constantly updating them. And so if I have that embedded relationship built in with those elements, then that's another thing that the computer is going to take care of for me as I go through and make modifications to the model.
Concept 4: User-Defined Rules
Concept four has to deal with user-defined rules. And there are a couple of ways we can do this. So one of them is I can put a dimension spanning these three different potential offices here. And let's say I want them to all be as equal as they possibly can. Well, with this dimension, I can hit this EQ button, and then it will spread these out evenly so that they get as equal as possible, and that'll allow me to define that I want these walls to be spaced equally between this reference plane and the edge of this stairwell. Another way that we could do that is if I were to have two walls, and I'll just kind of draw these out in the middle here, where I want them to always be a certain distance apart from each other. And so I can put a distance here, and I can say, well, I want that space to always be 5 feet. And then I can click on the dimension and lock it. And so now that spacing will always remain, even if I were to draw a dimension here and make this modification to say 8 feet. And you can see the walls don't move; they stay at 5 feet. And by using user-defined rules, I can lock that constraint, or I can place these to be equally spaced.
Concept 5: Hierarchy
To keep all of this data straight takes us to concept number five, which is the hierarchy. Revit uses a strict hierarchy of category, family, type, and instance. And so when we look at that, our category here for this door, for instance, is going to be doors. And then our family is single flush. Our type is going to be 36 x 84. And then our instance is going to be this particular piece of that door in the model. And so we could have multiple instances. You can see here I'm just kind of copying these around, but they'll all follow that hierarchy. And so if I look at, say, this door here and I make a change at the type level, then all of those doors are going to change. But if I make a change at the instance level by, say, changing the mark or the elevation above the still height, etc. There's a lot of different things that can be changed, then we'll only see that occur at that one element. So if you look at it like a tree, like it is a category, if a change is made at the category level, it impacts all of the families and all the types. If it's made at the family level, it impacts all the types. At the type level, it's going to impact all the instances. And then the instance level, it's only going to impact that one instance.
Concept 6: One Single Source of Truth
After using Revit for so many years, I feel like this one's more self-explanatory, but I totally understand that it's not for new users, and that is, Revit offers one single source of truth. And so if I were to go into my 3D view and look around and say, you know, I'm going to just take some of these things off and go through and delete walls and remove stuff because I just want to peek in on this stair, whatever it may be -- what I have to understand is that because this is a 3D model that consists of views like elevations, sections, floor plans that are cut from this database. By doing that, what I've actually done is deleted and removed those elements from our model. But there is good news -- we can always undo. And so if I were to undo back to where those things are, back to where they belong, then I'm in good shape. And I can see all of my stuff there. So, keeping in mind that deleting things is forever. And if we wanted to delete something or remove something from a view temporarily, we can always do hide and view by element.
Concept 7: Built for Teams
And for concept seven, finally, we'll talk about how Revit is built for teams. Through work sharing, multiple users can own different parts of the same model simultaneously. And it allows us to use a central model, which is located on a central server, or a lot of teams are now using Autodesk construction cloud to host their model, which allows you to access it from anywhere, and then a series of local models, which will represent each of the different team members that are working on the file. As Team Member One here is working on these work sets and elements, that would prevent Team Number Two from working on them or making modifications to them until this person synchronizes the changes back to the central. By synchronizing the changes, you're sending your modifications to the central model and then reloading all the ones that the other team members have made. And this works really well because it allows team members to all work on a large model at the same time without having to have multiple different files to work on.
Concept 8: More Than Just 3D Modeling
And in conclusion, our final tip here, or final concept, is Revit is not just a 3D modeling software. So we can do things with our model to create perspective views that are going to be used for rendering. It's in presentations to technical wall sections that are fully detailed out, showing all the different elements within the building and wall sections, all within the same model, which differentiates it from other software, because now we've got one platform controlling our entire project instead of having everything spread out across multiple files or multiple different models. So once you understand these rules, the software starts to work for you rather than against you. And this is something that'll give you the foundation to be able to understand the software in a way that allows you to take advantage of all of its functions.