Principles of Modeling in Revit |
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Revit is much more than a 3D modeler. It is built specifically for architects and has behavioral rules built into many of the architectural elements that make up the building. For example, walls usually are vertically extruded rectangular shapes; floors and ceilings are horizontal extruded shapes with constant thickness. These major building elements (System Families) use a restricted sketch-based approach because those restrictions make sense for these types of elements. This is one of Revit’s major differences compared with a generic modeler where you can model anything, any way you like. In Revit, the type of element you are modeling will present a more tailored set of creation tools.
You draw a wall by defining its start and end point, which will determine its position and length. The width of the wall and its height are determined by the wall properties. The wall becomes 3D immediately with each click of the mouse. Roofs and Floors, on the other hand, require a definition of a sketch that determines their outer shape while their thickness is what is defined in the Element properties of the Roof or the Floor.
Once the envelope of the building has been established with walls, floors, and roofs (the system families) you progressively add windows, doors, furniture, plumbing fixtures, and so on (standard fam-ilies) to the model. These elements rarely depend on the context of the building and are usually built off site and manufactured in some factory in real life. In Revit, a good selection of these elements is pre-prepared and saved in a library for use across multiple projects. These loadable elements are all created in the Family Editor using a combination of simple geometric forms that can be associ-ated with parametrically driven dimensions. For example, a chair can be created with a combina-tion of sweeps, blends, extrusions, and revolves. The same applies to a lighting fixture, a sitting bench, a plumbing fixture—you name it. Figure 6.19 shows samples of standard “loadable" family types. |
Figure 6.19
These windows and doors belong to the standard “loadable" family types |
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| In some cases, you need the full flexibility of the Family Editor in the context of your project. When you need to create a custom design feature tightly related to the context of the building or the landscape around it (entrance canopy, reception desk in welcome area, etc.) you’ll need a robust set of tools that are not available using the basic walls, floors and roofs. These types of elements are cre-ated using the Create tool from the Modeling tab in the Design bar (Figure 6.20) and they use the same features available in the family editor, and are referred to as “in-place families." Figure 6.21 shows a fireplace built as an “In-Place" Family. |
Figure 6.20
The Modeling design bar |
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Figure 6.21
Example of an In Place family |
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| Another workflow where free-form modeling comes into play is at the early stages of conceptual design, where massing studies are explored. These mass forms are done with the Massing tools, as combinations of various geometric shapes made using extrusions, blends, sweeps, and revolves. Again, with massing, the tools need to be flexible and not constrained to a specific use case. In Revit, the same set of primitive form making tools is available when making massing geometry. Figure 6.22 shows a massing study using Revit form making tools |
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