Revit Families - Content Creation from Manufacturers Written by: Peter Gehring, Synergis Director of Building Solutions

One of the biggest concerns of firms adopting the Revit platform products is the availability of content specific to their needs. While the out-of- the- box libraries and Autodesk’s Web Library (Content Distribution Center) contain many families (some manufacturer specific), there is never enough for the variety of building systems, furniture, casework and equipment that is necessary to represent graphically and informationaly in building projects.

While the Revit Family Editor provides a vehicle to create custom or manufacturer specific content, architects, engineers and planners do not always possess the necessary skills, or more importantly the time, to create this content on their own. With Revit adoption growing worldwide, there has become more and more content available on the web from a variety of resources or from others users sharing content they have created. These sites (Revit City, BIMWorld, and USG Design Studio) make thousands of families available for download. Even with so much content already created and available there is still a demand from the AEC community for manufacturers to begin supplying their own products in a Revit format, much like they have previously done in a CAD format.

In a previous Cadalyst Article, Rick Rundell (BIM-and-Building-Product-Manufacturers-1-2-3) discussed this topic. I will not repeat his points in this article. Instead I will show some of the options manufacturers have for creating this content and describe some of the steps, advantages, and disadvantages of the different methods.

One manufacturer that has already done this is Visa Lighting Their extensive, free, downloadable libraries of Revit family files (figure 1) not only contain physical representations of their products but also include the specific identity and engineering data that is critical for the Building Information/Performance Model which involves calculations, analysis and simulation.

Figure 1

Being able to include content with specified design and engineering properties (figure 2) Visa Lighting, helps architects and engineers quickly perform analysis on multiple design iterations and compare their aesthetics, performance and sustainability. By following this path, manufacturers’ cannot only save architects and engineers time creating specific content but they also become earlier, more valuable partners in the building design optimization.

Figure 2

This article is targeted to an audience of manufacturers who may not have any prior or extensive knowledge of Revit Projects and Families.

Revit Projects are databases that contain and present the geometry and information that represents a building project. Revit Families are files external to the project that are preloaded in Project templates; or loaded on demand into Revit Projects to represent doors, windows, furniture, casework, structural members, fixtures & equipment, etc. (figure 3).

Figure 3

Revit Families are created in the Revit Family Editor where the geometry is modeled, or imported, and the identity and engineering data is assigned. Revit Families have a file extension .rfa. Revit Projects have a file extension .rvt and can contain the families as content to be added (Figure 4).

Figure 4

Manufacturers have several options when deciding to create Revit Family Content. They may already have their products modeled in 3d formats using Inventor, Solid works, Pro/Engineer, etc. Ideally they would like to reuse these models and not have to remodel every product from scratch. Depending upon the complexity of these models, and the ability to export them out of the native application as a simpler model, they may find that this option is not always the best.

Let’s first look at a summary of the basic workflows and the advantages and disadvantages of the different methods:

Option1: Create from Scratch in the Revit Family Editor Option2: Create from an Imported Sat file in the Revit Family Editor Option3: Create from Imported dwg file in the Revit Family Editor

Option1: Create from Scratch in the Revit Family Editor

Workflow Summary

Launch the Revit application and start with the appropriate family template file

Create parametric geometry from extrusions, blends, revolves, sweeps and voids

2d cad and raster data can be imported for reference and leveraged for modeling

Create 2D representations with symbolic lines as necessary, add identity and engineering data, create Family Types for different sizes & properties

Family types for sizes created from parametric dimensions and formulas

For MEP content – add duct, pipe, and electrical connectors

Save and load the family (.rfa) into project templates (.rte) or projects (.rvt)

Advantages

Parametric geometry control for flexing model and adding formulas

3D Modeling can be kept simple to minimize bloating of projects

Multiple sizes of similar geometry can be built into one family file as types

MEP smart connections can be added to faces easily

Disadvantages

Need for understanding of parametrics and modeling in Revit

Duplication of effort if products are already modeled in another application

Option2: Create from an Imported Sat file in the Revit Family Editor

Workflow Summary

Use Export or Save As options to create file in .sat format from native application

Launch the Revit application and start with the appropriate family template file

Import Geometry into Revit Family editor with ACIS SAT (*.sat) import functionality

Create 2D representations with symbolic lines as necessary, add identity and engineering data, create Family Types for different sizes & properties

Family types for different sizes can be created by importing various SAT files for each size and setting the visibility on and off for different displays

Multiple size variations can also be exported as .sat files and imported into separate family files to load into projects.

Save and load into project templates or projects

Advantages

Leverage existing models (no remodeling)

Simple export import workflow

Disadvantages

Native model of SAT may contain modeling unnecessary for architectural needs and context resulting in slow performance in projects and bloating file size.

Multiple materials cannot be assigned to different pieces of the model.

No parametric dimension control for different sizes, only visibility control.

For MEP content - duct, pipe, and electrical connectors cannot be added to faces of SAT geometry. A workaround is necessary to create Revit geometry that connectors can be added to.

Option3: Create from Imported dwg file in the Revit Family Editor

Workflow Summary

Product modeled in AutoCAD (or imported in AutoCAD)

Parts assigned to layers for later material assignment in Revit

Model simplified in AutoCAD if imported with unnecessary internal parts or details

Geometry imported to the Revit Family Editor with AutoCAD DWG (*.dwg) import functionality

Create 2D representations with symbolic lines as necessary, add identity and engineering data, create Family Types for different sizes & properties

Family types for different sizes can be created by importing various dwg files for each size and setting the visibility on and off for different displays

Multiple size variations can also be exported and imported into separate family files to load into projects.

Save and load into project templates or projects

Advantages

Leverage existing models (no remodeling)

Ability to assign different pieces of the model to different materials in Revit

Disadvantages

Native model may contain modeling unnecessary for architectural context that can slow performance

AutoCAD becomes a necessary intermediate workflow step between native application and Revit

For MEP content - duct, pipe, electrical connectors cannot be added using dwg geometry. A workaround is necessary to create Revit geometry that connectors can be added to.

The preceding was meant to be a summary of the different options. Next I’d like to give more detailed step by step explanations.

Option1: Create from Scratch in Revit Family Editor

Start new Revit family (.rfa) from appropriate template specific for content type (figure 5). This is important because it sets the behavior in the project environment for snapping to hosted objects (doors to walls, furniture to levels, light fixtures to ceilings), and how objects are tagged and scheduled in projects.

figure 5

In the Revit Family Editor model the geometry with extrusions, sweeps, revolves, blends and voids (figures6 & 7).

figure 6

figure 7

Add dimension, identity, design and engineering parameters (figure 8)

figure 8

Create 2d representations (symbolic lines) as necessary

Create coarse, medium and fine detail levels (Set visibility for specific views- figure 9)

figure 9

Save file (.rfa) and Load into Projects (.rvt) from Family Editor

Or Load from Library in Project (figure 10).

figure 10

Option2: Create from Imported Sat file in Revit Family Editor

Model or use existing model from native application.

Simplify model and suppress extraneous details

Save Copy As SAT format in Inventor (figure 11)or export SAT format from other modeling packages)

Some programs give option to set SAT version (Revit can import versions 4 through 7)

figure 11

In Revit, File >New Family (figure 12).

Select appropriate family template (figure 13).

This will set the object’s desired behavior in the architectural context and for scheduling.

figure 12

figure 13

Use the Import/Link Cad Formats from the File pull down to import the SAT file (figure 14).

figure 14

The Object comes in as an imported symbol and is not editable as Revit Geometry (figure 15).

figure 15

For each different size you would import an SAT for that size within the same Revit family file; then set as types with visibility settings; or create another family file for each size.

As imported geometry these 3D objects cannot be exploded to turn into Revit Geometry (figure 16).

figure 16

As an imported symbol this SAT geometry is all assigned to “layer” 0

This limits the ability to assign different materials to the discrete parts in Object Styles (figure 17).

figure 17 When the material is set to the Object Styles layer for imported objects, all the parts

display the same material (figure 18).

figure 18

Just as when creating content from scratch in the Family Editor, imported SAT geometry family files can have identity, design and engineering data assigned as parameters in the family (figure 18).

figure 18

Although the imported SAT geometry can be dimensioned and aligned to, it cannot respond to dimension parameter constraints for size modification like native Revit geometry.

Sat imported geometry

Native Revit geometry

Finally like creating geometry from scratch, save and name the file (.rfa)

Load into Projects (.rvt) from the Family Editor (figure 19) or from the Project itself (Load from Library)

Then place the family as a component when needed (figure 20)

figure 19 figure 20

Option3: Create from Imported dwg file in Revit Family Editor

Model in Inventor

Extraneous parts are suppressed and complex models can be simplified with “Level of Detail” Option (figure 21)

figure 21

Export out of Inventor using AEC Exchange option Save As DWG Solids (figure 22).

figure 22

Start AutoCAD Application

In AutoCAD the geometry comes in as a block all on layer “0” (figure 23)

figure 23

Create new layers for each discrete material (figure 24).This can be preset in a template.

figure 24

Explode or refedit the block (figure 25).

figure 25

Assign parts to different layers (figure 26).

figure 26

Save the File

In the Revit Family Editor start with the appropriate template, in this case we will use the furniture family template furniture.rft (figure 27).

figure 27

Companies can create their own family templates with manufacturer parameters (model numbers, names, cost, etc.) and materials already.

In the Revit Family Editor use the Import/Link CAD formats to browse to and import the modified dwg with geometry assigned to layers (figure 28).

figure 28

In the Revit Family Editor’s Object Styles, materials can be assigned to the imported symbols “layers” (figure 29).

figure 29

As we have seen when creating families from scratch, or from SAT files, we can then assign identity, design and engineering data as parameters in the family.

We also have the same limitation as imported SAT geometry that we cannot fully explode nor constrain/flex the imported dwg geometry by dimensions.

Finally, like creating geometry from scratch or SAT import, we save and name the file (.rfa), Load it into Projects (.rvt) from the Family Editor or from Project itself (Load from Library).Then place as a component where needed.

This article did not go into detail about creating MEP products. These would be imported into the Revit MEP Family Editor where duct, electrical and piping connectors can be added. I hope to create a follow up article covering this.