This chapter will take you through fundamental principles and some compelling use cases using the family editor.You’ll acquire the following skills in this chapter: con-◆ Understanding t
Trang 1Chapter 10 Creating Custom 3D Content
In this chapter, we’ll explore how to build custom model elements for use in a project We’ll look
at how parametric constraints and parameters can be used to build flexible and time-saving tent Building intelligent content is a key feature of Revit and deserves an entire book in its own right, but we will introduce you to some useful concepts and get you going This chapter will take you through fundamental principles and some compelling use cases using the family editor.You’ll acquire the following skills in this chapter:
con-◆ Understanding the different types of families and their application
◆ Leveraging nested families for efficiency and flexibility
◆ Building relationships between parameters with formulas
Modeling Parametric 3D Families
As a design progresses from the generic to the more refined, you’ll need to add more detail and ism to your components This process involves more faithfully representing what will be built and will require you to start building your own families Although many types of families are provided out of the box or can be downloaded from websites such as the Revit web library or revitcity.com, you’ll inevitably reach a point where your design intent isn’t matched by existing content (Figure 10.1) This is when you’ll need to dig into the Family Editor and create new building components
real-Figure 10.1
This sun-shading element was imple-mented as a custom Revit family
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Up to now, we’ve covered many of the basic principles of families, including family categories, form making, and constraints; but we haven’t put this into practice beyond some simple shapes In the following sections, we’ll look at more advanced techniques used to make parametric families with embedded intelligent behaviors
Choosing the Right Family Template
Every family belongs to a category, making it important to assign new families correctly so they can
be controlled logically when loaded into a project Revit provides a series of pre-made templates (Figure 10.2) for most families
Figure 10.2
Premade model family templates
When you decide to create an element on your own you need to select the correct template These premade templates are time savers, because they already have the right category assigned, provide the most important reference planes that drive the behavior and geometry, and in some cases include text notes to help explain how the family will work in the context of a project Figure 10.3 shows a window template file, which includes text indicating the exterior/interior of the wall; parametric dimensions for width, sill height, and opening height; and a sample host wall.The reference planes that appear in the family environment are the essential bones of any family They establish the critical dimensional rules for the family, define the origin, and provide refer-ences that can be dimensioned to All starting templates provide at least two reference planes to start with, because without reference planes, you can’t make parametric content or dimension it in the project
Types of Families
For model-based families, there are two high-level types: 2D and 3D 2D families are used for making 2D details of the model, and 3D families are for making 3D geometric representations Note that 3D families can contain nested 2D elements as a way to embed details directly into content
For 2D families, you can make standard detail components and line-based (2-pick) detail ponents 3D family types include various host-based types (floor, wall, roof, and ceiling), profiles,
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Figure 10.3
Plan, elevation, and 3D view of a template for windows Text notes, reference planes, and dimen-sions have been preset
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Host-Based Families
Windows, doors, skylights, and lighting fixtures are all discretely manufactured objects, but they have something in common: They’re installed into something else Without the wall, ceiling, or mounting surface, the object has no place to ground itself in a typical building project For these types of elements, Revit provides host-based families and templates When you need content to have an explicit relationship with a wall, floor, or roof, then a host-based family is absolutely the way to go These are the most common types of families used in Revit, and include components such as doors, windows, skylights, solar panels, light fixtures, and balusters Assuming you’ve placed some windows and doors in a Revit project, the benefits and behaviors of host-based families need not be covered here Figure 10.4 shows several examples
Figure 10.4
Examples of based families
Roof-based skylight Ceiling-based lighting fixture44831.book Page 282 Friday, October 12, 2007 12:31 AM
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Windows and doors don’t exist in the model in isolated, abstract form, but are always hosted by
a wall This is why you see a sample host element (a small wall, roof, or floor) when you open a host-based template The sample host is used to help you construct the family so it behaves prop-erly in the model—to give you a context in order to build the family so it correctly relates to wall thickness
Note that the host that exists in the family template (such as the wall in the window template) isn’t loaded in the project when you load the window—it’s present in the Family Editor only as a reference to help you understand how the window will work when loaded into a project Only the geometry and reference planes that you create end up in your project
Profile Families
Many architectural details have distinct cross sections that run in a linear fashion Geometrically, these details are constructed by extruding that profile along a path, which maps to how many of the elements are physically manufactured Baseboards, cornices, handrails, and mullions are all examples:
Revit provides special templates designed for elements like these To create one of these ments, you choose to make a profile family Then, sketching with 2D lines, you define the shape of the profile cross section Like many sketches in Revit, the profile must be made of a single closed loop
ele-of lines—multiple loops will lead to errors downstream For example, if you loaded a mullion file like that shown in Figure 10.5 and then tried to use it in a mullion family, you’d get a warning message Delete the inner loop of lines to get the mullion to work properly
pro-Figure 10.5
Invalid profile:
Profiles with more than one loop won’t work in a project
How do you make something like the shape shown in Figure 10.5? Although you can’t have multiple loops in the profile family, you can import a detail component into the profile family, as there is no penalty for having multiple loops of lines in the detail component To control when this
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level of detail is visible in the model, you can set the visibility of the detail component so it appears only at fine levels of detail Continuing with the mullion example (Figure 10.6), take these steps:
1. Load a complex detail component derived from a manufacturer into the mullion profile family
2. Trace the loaded component with a single loop of lines
3. Set the options in the “Family element visibility settings” dialog to show the detail only in fine views
Figure 10.6
On the left is the profile sketch, on the right a detail component
4. Load the family into the project
5. From the Project Browser, locate the rectangular mullion profile and duplicate it Open the Type Properties dialog, and assign the new profile to the mullion family (Figure 10.7)
Figure 10.7
Choose the profile from the mullion’s Type Properties
Profile sketch lines
Detail component44831.book Page 284 Friday, October 12, 2007 12:31 AM
Trang 7Many companies that sell finish moulding provide 2D CAD drawings that you can import directly into a Revit profile family This is a great time saver and will keep you from having to draw complex profiles from scratch
Profiles can be used for many different purposes To accommodate more specific behavior
as well as categorization, five different profile family templates are available: Profile.rft,
Profile-Rail.rft, Profile-Reveal.rft, Profile-Stair Nosing.rft, andWall Sweep Profile.rft Be careful to select the correct one, because Revit looks only for specific profiles depending on what you’re making For example, a mullion family won’t let you choose a wall-sweep profile; only mullion profiles will show up in the list
2D Line-Based Families
Not all elements need to be modeled in 3D; some are represented using 2D detail drawings Most details can be drawn using lines and filled regions, but these are inherently difficult to maintain and reuse For details that are likely to be used in other drawings or projects, you should create detail families With Revit, you can make stand-alone detail components or line-based families The line-based family is great for making elements where length is the primary variable
The 2D line-based template (Detail Component line based.rft) can be useful These families let you draw a detail element as if you’re drawing lines, but the component can contain as many lines and filled regions as you want For example, you can draw a detail component that represents plywood (lines + wood hatch) with two clicks of the mouse
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families are molding details, sun shades, grating, and any other elements that have length as their primary variable Figure 10.9 shows a 3D chair family that adds chairs as the family is made longer
Figure 10.9
3D line-based chair family
With two clicks of the mouse, you can quickly add rich 3D content to your model Figure10.10 shows a sun-shade example The brackets at the left and right side were modeled in the family using solid extrusions and constrained to the left and right reference planes The blades were mod-eled as sweeps between the two horizontal reference planes, using a profile When placed in the model, the sun shade can be stretched dynamically
Making a Plywood Line-Based Family
To make a plywood line-based detail, you can use the line-based detail template In the line-based ily template, you create a filled region between the left and right reference planes and assign a plywoodfill pattern to the region As long as the left and right lines of the filled region are coincident withthe reference planes, they will follow the planes when the family is placed in a project, and drawn Thecross-sectional dimension of the filled region can be driven by a Thickness parameter, which is set to 3⁄4˝and can later be modified if you need new types:
fam-When the plywood family is loaded into the project, you can make a symbolic 2D plywood tion with two clicks that define the length Once you’ve placed the plywood, you can reselect it and drageither end using the blue grips to stretch the detail Compared to using a filled region in the project, thismethod provides parametric constraints, reusability, and incredible ease of use
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Figure 10.10
3D line-based sun shade family
Work Plane– and Face-Based Families
For elements that need the flexibility to be placed on any model face, such as electrical outlets, signage, or coffee pots, there are work plane– and face-based families These families attach to any surface of the model during placement; you can later rehost them to any other surface if need be Any time you have a component that needs to be installed on multiple types of hosts, think of making the family face based
Face-Based Families
You create face-based families with the template Generic Model face based.rft When you open the template, you see an abstract host surface on which you can model your family When you load your family into your project, the host surface in the family maps to whatever face you choose
in the project, and your family reorients to sit on that face automatically The face you choose can
be anything from another family to geometry of a linked file An example of a face-based family is
an HVAC supply register, which you need to be able to place on walls, ceilings, or even floors Figure 10.11 shows another application of a face-based component, where the curved surface doesn’t have a work plane
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Work Plane–Based Families
Work plane–based families are placed on the active work plane of the current view Every view has
an active work plane that you can manipulate using the Work Plane tool; see Chapter 6
Be sure to give the family an appropriate category before loading it so you can control its bility and graphics
visi-Rich Photorealistic Content (RPC) Families
When you’re rendering a view, it’s possible to substitute real model geometry (the family) for highly photorealistic images (such as Archvision content, available at http://www.archvision.com/) For example, a simplified stick figure can turn into a real-looking person when the view is rendered (Figure 10.12)
This can be a cool feature when you’re rendering, and it makes rendering faster because there
is no complex geometry to render You can create plants, cars, and people using these families
Assigning a Rendering Appearance
RPC families are specialized and have specific behavior when rendered In addition to the 3D and 2D representation that you normally add to a family, you can also assign a rendering appearance
to the family This appearance shows up only when you raytrace a 3D view
You create RPC families using the template RPC Family.rft RPC appearances can only be added to the Entourage and Planting families When the family is set to either of these categories,
a Rendering Type parameter is enabled in the Settings Family Category and Parameters dialog RPC families in these categories have additional type parameters (located in the Family Types dialog; see Figure 10.13) to control the associated RPC file used when the family is rendered in a project, along with specific properties In Figure 10.14, RPC properties of a car allow you to specify the license plate and window tinting!
Figure 10.13
RPC parameters in the Family Types dialog44831.book Page 288 Friday, October 12, 2007 12:31 AM
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Figure 10.14
RPC Properties dialog for a car family
Detail Component Families
As you’ll see in Chapters 17 and 18, a typical workflow to complete a Construction Document set involves enriching the model with 2D details in detail views These detail elements typically depict cross sections or elevation views of elements that don’t need to be modeled in full 3D (to do so would only bog down the model and not add much value) For this use case, you can use detail-component families to add detail to model or drafting views; these details are visible only in the view in which they’re placed Examples include blocking, studs, steel sections, bolts, flashing, and
in which they’re placed but are otherwise free to move around the model and aren’t connected to any host objects
Many generic templates have been pre-made for you with the appropriate category selected Examples include Furniture.rft, Furniture Systems.rft, Mechanical Equipment.rft, and Plumbing fixture.rft, to name a few
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Curtain Panel Families
Curtain walls and aluminum storefront systems are composed of mullions, glazing panels, operable windows, and doorways In Revit, the Curtain Wall tool organizes all these components into an integrated system of parts For panels, the default solid and glazed options are usually sufficient Adding doors and windows to a curtain wall requires you to make custom panels in the Family Editor Figure 10.15 shows a curtain-wall door family in the Family Editor—you’ll notice that these templates don’t contain host walls as other door-family templates do
Figure 10.15
Double-panel wall door
curtain-Keep this in mind: To add doors to a curtain wall, you must use one of the special curtain-wall doors—you can’t place a standard door into a curtain wall Use the Door - Curtain Wall.rfttemplate to create these families Essentially, they’re like regular door families, but the width and height are dynamically tied to the size of the curtain-wall cell in which the door is placed As the curtain-grid spacing changes, so does the size of doors placed in the wall As you can see in Figure 10.16, the door family adapts to the size of the curtain-grid spacing
Figure 10.16
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Family Categories and Parameters
In every Revit family, settings control specific behavior of the family and set the category Depending
on what category you assign the family, you can get a different set of type parameters and based parameters For example, in a window family template, preset parameters for Sill height, Width, and Height are hard-coded into the family (Figure 10.17) In a furniture family template, you don’t see these parameters
category-Figure 10.17
Premade family parameters for windows
Another set of parameters affects the entire family based on the category it belongs to You can access these settings by choosing Settings Family Category and Parameters In the resulting dialog (Figure 10.18), you can set the category and also adjust some other parameters that affect how the family will behave when placed in a model
Figure 10.18
Family Category and Parameters dialog44831.book Page 291 Friday, October 12, 2007 12:31 AM
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In the figure, the Furniture category has three family parameters listed: Work Plane–Based, Always Vertical, and Shared Remember that changing the active category at the top of the dialog may enable or remove family parameters displayed in the bottom of the dialog Let’s briefly review what these parameters do:
Work Plane–Based Enabling this option allows the family to be hosted by the active work plane when placed in the project or nested into another family Any nonhosted family can be set
to be work plane–based Any family using the generic template (furniture, site, casework, and
so on) can be set to work plane–based, as such families aren’t required to be hosted by another component (like doors or windows)
Always Vertical This parameter keeps a family oriented in the positive z direction when placed in a project In most cases this is desired, because levels are always horizontal But when you have sloped floors or sloped site conditions, you may want the component to be oriented perpendicular to the surface it’s placed on Parking stripes and cars placed on a sloped slab
of a parking structure are examples where making the family not always vertical makes sense (Figure 10.19)
topo-Shared This parameter controls the visibility in a project of a family that is nested in another family component You may choose to nest families to create assemblies or save time modeling components that repeat Nesting has implications when you need to tag or schedule the family For example, consider a window assembly with a main light and two side lights, one on each side If the design intent is that the window is to be tagged and scheduled as a unit, then the fam-ilies will be nested into a host family and the Shared parameter will remain unchecked In this situation, only the host family (the family containing all nested windows) will schedule If the intent is that the assembly is constructed from separately purchased units and assembled on site, then the nested families should have the Shared parameter checked This will allow each nested window to appear on the schedule as if placed separately
Rendering Type This parameter is enabled only for families set to the Entourage or Planting category For Entourage, you can set the Rendering Type parameter to Geometrical or Archvi-sion RPC If you set the value to Archvision RPC, Revit adds the RPC Filename parameter to the Family Types dialog You can then select the desired RPC filename for each type For Planting, you can set the Rendering Type parameter to Geometrical, Accurender Procedural Plants, or
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