Delve into the intricacies of Revit software as we explore the world of parametric objects, bi-directional associations, and user-defined rules. Learn how to effectively navigate through different file types and understand the hierarchy of elements within the software that ensures efficient project management and modification process.
Key Insights
- Revit offers two primary file types, .rvt and .rfa. The .rvt file acts as the main base for all work in Revit, while .rfa files, also known as Revit families, include elements like doors, windows, and other such items used to develop a Revit model.
- The software operates based on parametric objects and their relationships, which involves items with changeable parameters. There is also a concept called bi-directional associations wherein changing something in one location automatically updates it everywhere else in the model.
- Revit operates on a hierarchical system where each element is part of a category, and any modification on the category level impacts the family, type, and instance levels. Understanding this hierarchy is crucial to avoid unintentional changes in the project.
This lesson is a preview from our Revit Course Online (includes software) and Revit Certification Course Online (includes software & exam). Enroll in a course for detailed lessons, live instructor support, and project-based training.
Hello and welcome to BIM 101 Introduction to Revit. To kick off the course, I would first like to start by covering a few primary concepts and terms to make sure that we're all on the same page. The first concept I'd like to review is file types.
I've downloaded the course files from the resources tab, extracted the zip file, and this is what you get. So, within it, you can see that we have three different project types. Two of those are associated with Revit, and one is just a PDF here.
The first file type I'd like to discuss is a project type. The project is identified with the extension.rvt, and that's going to be the main home base for pretty much everything that we do in Revit. So, similar to AutoCAD, where you have a.dwg file as your primary file type, that's what our.rvt file is going to be.
The other one that we'll use considerably in this class is a.rfa file, and.rfa is how we identify Revit families. Revit families are items like doors and windows. In the example that you see here, we have a lavatory, so a wall-mounted sink here, and we also have a couple of title blocks. It can be any number of things that we use to help develop our Revit model further. The next concepts I want to cover are the primary concepts for the program itself and how it operates, and we'll also touch on a few terms as we proceed through this.
So, the first one that we want to talk about, and it's one that gets thrown around quite a bit, is going to be parametric objects and their relationships. So, whenever you hear the term parametric, what it’s really referring to is an item that has parameters that we can potentially change. For example, if I were to use this double door, this door here, as you can see through the type selector, is 72 × 84, and those are parameters that define the width and height of the door.
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The family itself is called 'door double glass, ' so what we're looking at here is a double door that has glass within it. Some of the parameters, more specifically, will be located within the edit type dialog, and we will go through all of this in great detail during our user interface lesson. But you can see the parameters that we're referring to that make this family parametric are the width, height, and also some material parameters and other dimensional parameters that identify the thickness of the trim and the width and where they're located.
The next concept I’d like to cover is bi-directional associations, and this is really just a fancy term for if you change something in one location, it changes everywhere else. So, one of the common misconceptions about annotations within Revit is that they're really just a tag that you input information to, but what they really are is a tag that relays information back to you based on the element. So, this is a room tag that shows us a number and an area, and if I were to pick the room element here, you can see that those parameters are actually part of the room itself. If I were to change any of those such as the room number here, it will change within the room itself.
If I put it back to 112, it will update on the tag. So, the bottom line here is that if things have this bi-directional association, the beauty of it is that you change it once, and all other elements associated with it will change as well. This is probably one of my favorite Revit concepts here, and that involves user-defined rules. We’ll use this a lot in our day-to-day work because sometimes we'll be fitting out a space like a mechanical room or maybe a lab support room that has a specific dimension that's required. So, what I’ll do is draw a dimension, and if I say that I always want this wall to be 11 feet or 11 foot 11 and 1/16 inches in this case from gridline 3, I could lock that dimension, and no matter where either gridline 3 moves or this wall moves, that dimension will always stay at that 11 foot 11 dimension. There are other types of user-defined rules that we can implement as well.
Some of those could involve using formulas to develop how things are going to react to each other or whether an array has a certain number of items associated with it. These are items that we’ll cover as we progress through the course. A few terms I’d like to cover involve some of the items we use within the program. In this case, we’d be looking at a view here, and a lot of times I'll call this a floor plan view or a plan view as we go through the video, so if you hear that, it should trigger that we’re in a floor plan view. Another one you’ll hear often is when we talk about levels, and when we’re talking about levels, we’re not necessarily talking about Level 1, Level 2, roof, or parapet, but we’re actually talking about the physical element that makes up the levels that determine the height of these different items here.
So, you can see here, Level 1 is an actual datum element that we will use, and it happens to also create our Level 1 floor plan for us. Just to keep it clear and make sure that we're all on the same page, when we’re talking about levels, we could also be talking about the datum element, or we could be talking about the actual plan view that we’re looking in. Another important concept to understand here involves the hierarchy of the elements within Revit. This can be a little difficult to wrap your head around at first, but once you get it, it really clicks, and it helps you modify elements as you go through and develop your project.
So, everything within this program works under this hierarchy. Every element that you see here is part of a category. If I were to use walls as an example, the category we’re dealing with here is walls.
The family we’re working with is 'basic wall.' You can see the pop-up there, and then the actual type we're dealing with here is 'interior four and seven-eighths partition.' The instance is the object that I have selected. When we’re talking about the hierarchy of certain elements here, we're going to go with category, family, type, and instance. This is really important because it determines how elements get modified throughout the project. If an object is modified at the category level, then the family, type, and instance all get edited as well.
A good example here would be a door. If I pick on this door, this door is part of the doors category, it is the single flush family, and the type is 36 × 84. So, what we have here in this dialogue box, which is the properties palette, are the instance parameters, meaning only this one instance will be modified if I change any of these values here.
If I were to go one level up to the type parameters, located here in 'edit type, ' and make a change, then all of the instances of 36 × 84 within this project will be modified. This is really important to understand because you could inadvertently make a change to something that you didn’t plan on doing. If I were to change the width to say one foot, which is a pretty ridiculous width for a door, but it’s a good example because you'll see it graphically here. If I hit okay, you can see that all of my 36 × 84 doors are now 12 × 84, and that’s throughout the entire project.
If I were to go to Level 2, you’d see the same thing happen here as well. The beauty of Revit, though, is that like a lot of programs, we have an undo feature, so I can undo back to where I have normal door sizes again. But the moral of the story here is that if you do have to change a door, and we'll go through this process in a later lesson, you’re going to want to make sure you use a different type instead of just modifying one that’s already there. In the next video, we’ll go into more detail and talk about all the different elements in the user interface, and I’ll probably answer some of the questions that came up as I was going through this introduction.
