Model Categories

Model Object categories, the first tab in the Object Styles dialog, includes all the real-world types of objects typically found in buildings. These object categories include the usual elements such as walls, floors, roofs, and furniture, along with other categories that makes sense in an architectural project. For 2D elements that represent real-world objects, the category Detail Element is provided. Examples of 2D detail elements are insulation and detail components that represent real objects but are represented only in detail views. In Revit, these objects are not modeled as 3D elements, but added as 2D representations, as shown in Figure 2.4.



For elements that don’t fit into any obvious category, there is the
Generic Models category. This can be used for objects such as fireplaces, theatre stages, and other specific design elements. If you’re not sure exactly what you’re making, you can always create it as a generic element. If you later decide that any element needs to be recategorized, that’s not a problem—you can reassign the element to a new category at any point. With the exception of the detail elements, model elements appear by default in all views.

In other words, if you draw a wall in plan, it will show up in any other applicable plans, elevations, sections, and 3D views. Remember, you’re working on a single building model—all views in Revit are just different ways to look at the model. Detail components, on the other hand, appear only in the view in which they were placed. As we’ll discuss in more detail shortly, you can turn on and off the visibility of any category or element, in any view.

For example, say you’ve placed furniture in your model. The furniture is 3D geometry and will be visible by default in many views. Revit lets you turn off the visibility of the furniture in one floor plan while leaving it visible in another floor plan. The furniture isn’t deleted; it’s made visible or not depending on the information you need to convey in particular drawings. Because model elements appear in all other views, two types of graphic representation are defined for each category: projection and cut, as shown in the Object Styles dialog in Figure 2.2.

The projection graphics define the graphics for the element in elevation, 3D views, or any other view where the element isn’t being cut by the view. The cut graphics define how the element will look when cut by sections and plan views. Typically, the section cut graphic is bolder than the projection lines, to emphasize that the element is being cut by the view plane. (Surface and cut patterns are always drawn with line weight 1 and can’t be made thicker.) Figure 2.5 shows how wall line weight differs between the cut and projection. Also notice that patterns are applied to the walls and floors. Patterns can be added to give additional graphic representation to a material and are always drawn with a thin line weight.



Categories also make it easy to interchange elements. You can swap out elements of the same category with a few clicks of the mouse. This streamlines the process of editing the model by limiting choices to those that make sense. For example, you can swap a lighting fixture with another lighting fixture by selecting the element and then seeing what other lighting fixtures are available in the Type Selector. Choosing another type swaps out the type instantly.Revit is smart about this interchange—it offers only different types of the same category of elements. For example, when you select a door, you don’t get a list of plumbing fixtures to swap it with; you get a list of other door families.