The Workflow Between Revit Architecture and Autodesk Inventor

Micah Peterson and Shobhit Baadkar
Technical and Solutions Specialists, Microdesk

It’s been a few years since Autodesk’s acquisition of Revit Technology Corporation back in April 2002. This resulted in a parametric building modeler being marketed towards the architectural industry in the form of Revit Architecture. Around the same time, Autodesk had another parametric modeler targeted for the manufacturing market segment called Inventor. Fast-forward six years later; now architectural firms who were the early adopters of both pieces of technology are really pushing the envelope of parametric modeling. As the industry evolves towards integrated project delivery, bleeding edge users are equally pushing the envelope of interoperability.

Bringing Inventor files into Revit may seem a bit bleeding edge; however it’s not something you would use every day. This workflow does bring some exciting possibilities when you combine the mechanical design capabilities of Inventor with the architectural design capabilities of Revit Architecture. Some of the advantages of the Inventor and Revit workflow are being able to do some of the following:

• Take advantage of the swift workflow in Inventor to build geometry and quickly increase the accuracy of your Revit family library.
  
• Give a more realistic rendering to a client who has specific hardware needs.
  
• Bragging rights to your fellow colleagues.
  

In this article, we will show you how to create a faucet in Inventor and import that geometry into a Revit family for use in your architectural project.

Before we do that, however, let’s get a few things straight. If the entire focus of your project is your faucet and you want that to be highlighted in your eventual render, then please don’t use Inventor. Bring your Revit model into 3dsMax and create the faucet and render there. Also, if you are planning on manufacturing your faucet, don’t use the same faucet assembly to import into Revit. As we will explain below, for this process, you are modeling with presentation viewing and rendering in mind. Because of this, there are some alternatives to modifying your model to manage the file size as well as be a little creative.

Now that we’re clear, let’s get started!

Getting Content Information

Start out by finding the specific piece of hardware you want to model. In this case, you’ll be modeling a faucet designed by Moen. Some manufacturers may have .DWG files on a website, but for the more aesthetic hardware, you’ll most likely get PDF’s, which will work in this case.

Once you have decided on your product, get a good concept of the size and shape of your model using the documents you gathered. If the part is very well documented, you may be able to jump right into modeling your faucet in Inventor. However, in this case, the neck of the faucet is a fairly organic shape without any specific data and will require a loft using a number of section profiles. Because of this, we’ll use a background image as the basis for our sketch.

We want to emphasize this point: Sketching by using a background image will not produce a technically accurate drawing that will be suitable for manufacturing. It does however produce a great model for use in a Revit family.

Above, you’ll see the profile we used to model the neck. This was taken from a PDF on the Moen site. We did a simple print-screen and then cropped out this section into a .bmp file since the background image in Inventor must be an image file (TIFF, PNG, GIF, BMP, JPG all work).

Modeling the Content in Inventor

Once you have this image saved, open up Inventor and create a new part file under your current project. Then draw a base sketch on the XZ plane that will serve as the first section of our eventual loft. The sketch should be dimensioned to the diameter of the base of the neck (or as close to a good estimate as you can in this case).

After drawing the initial sketch, ensure that it is visible in your browser prior to adding the background image.

Open your Application Options menu (Tools > Application Options) and select the Colors tab. Under the background section, choose Background Image and then click on the folder icon below it to select your background image file. Navigate to the image file you have previously created and open it. Click OK or Apply in the Application Options menu and you’ll see your background image appear.

Now that you have it set up, you’ll need to align the previously drawn base sketch with the bottom edge of the neck. You’ll notice that the background image doesn’t change, regardless of zooming or rotation. You may want to use the manual Zoom tool rather than the scroll wheel on your mouse in order to get a little more precise zoom.

When your sketch is zoomed and panned to the proper location (with the first profile line aligned with the bottom of the neck), start drawing section lines (using construction line-type) along the path of the neck background. (Be aware of your mouse movement because zooming or panning without being aware can throw your section lines way off, requiring you to redraw them.) We used six section lines in this example, but you certainly could add more in order to create an even smoother loft. However, each section line will add another couple of steps and may not have much benefit to your loft.

After your section lines are drawn, draw a construction spline that runs through the midpoint of all of your section lines. Once you have your spline drawn, finish your sketch.

Follow the picture below for instructions if this is unclear.

Now you will add work planes that align to each section line and follow the path of the spline you just drew. To do this, select the Work Plane tool, and then click once on the midpoint of one section line. Click a second time on the curved spline to create the work plane. This will align the work plane properly along the path of the neck.

The pictures below show the process for adding a work plane and what you should eventually have. (Your picture may vary depending on how many section lines you created.)

Ok, so far a lot of setup, but now you’re actually going to get to create some profiles and from there it’s only a few clicks to create your lofted part.

Since you drew the section lines as close as possible to the actual width of the neck, it makes sense to use the end points of those section lines as the basis for the circular profiles on each work plane. To use them, you’ll need to first start a sketch on your first work plane and select the Project Geometry tool on your tool panel. This tool will allow you to bring in line work from geometry that is not currently part of the active sketch… like those section lines.

All you have to do is select the appropriate section line for that work plane and it will pull that line at the proper length and orientation to your current sketch.  Once this is done, you can then draw a circle that hits both end points of that projected line and you are done.  This is an example of where you could be a little more creative by using an ellipse instead of a circle (or any closed shape for that matter).  This is up to you and the needs of your client.

Below are the steps for projecting the section line, adding the profile, and the end result.

The final step is to use the Loft tool to connect these profiles into a 3d model. Open the tool and select the profiles, starting at one end and ending on the other. All other default options should be fine. Make sure that when you choose your profiles, you choose them in the correct order. You’ll see what happens when the order is a little off when you get to the handle.

Last but not least, its good practice to turn off your work planes and sketch visibility so that when you insert this part into an assembly, all those elements don’t come with it.

For your next trick, you’ll create the handle, which also involves a loft.  This process should be a little bit quicker since you already know the basics of what is required, but there are some differences which we will point out as you go along.

You’ll start off by creating the base of the handle knob, shown below. This is not very complex as it involves a basic vertical sketch and a revolve feature, so we'll let you create that on your own.

The handle portion is what will require a loft and to do this you need to draw another outline sketch. While you certainly could go through the process of creating another background image with a top view of the handle, in this case we just used a measurement for the total length of the handle and then did approximations for the section lines based upon what we thought would look good. This is another example of understanding the needs of your client. The one we used is shown below but yours could certainly vary depending on your needs.

We would recommend dimensioning your section lines with rounded off numbers in order to make it a little easier to modify later with parameters if you were so inclined.

When your outline sketch is done, you’ll need to add a work axis just like you added the spline to connect the sections on the neck part. The axis should be based off of the x-axis but raised to a height mid-way up on your base knob. You’ll use that to create your work planes. The steps are the same as the lofted faucet neck. The only difference is that instead of the spline, you use the horizontal work axis. The steps are shown in the picture below.

Just as with the neck part, you will then add sketch profiles to each work plane centered along the work axis you created. These can be any closed loop.

Once you have the sketches created, you can then loft them together.  As you can see in the picture below, the order of selection can drastically change the final result of the loft, in both good and not so good ways.

As with the neck part, turn off all sketches and work planes before you finish your part.

Neither the base of the faucet nor the base of the handle is very complex, so we’ll show you our parts and you can design from there. Make sure, however, that you plan for each part to be assembled together. Many times it is easier to add a small feature that might not actually exist in the real life model in order to make your assembling job much easier. Again, since we are only worried about the looks of the model and not its manufacturability, this will work just fine.

Once you have finished creating the remaining components above, you will use the basic assembly constraints to piece them together.  Again, it’s about looks, not functionality. So if both knobs turn too far or aren’t precisely in the right place, don’t waste time trying to get it just right when no one will know the difference after importing it into Revit.

The final step is to save a copy of your assembly into the .SAT file format, which can be imported by almost any CAD application.  See the picture below.

At this point, you’re ready to import this file into Revit and use it in your model.

Congratulations!  You’re half way there!

Bringing the Content into Revit

Start up Revit Architecture 2009. 

At the Recent Files screen, click on the Browse button under the Families category. Navigate to the Plumbing Fixtures directory. Select Sink Vanity – Round.rfa and click the Open button.

In this particular family, remove the solids that represent the default fixtures of this sink.

Go to File > Import/Link > CAD Formats. Locate the previously exported file from Inventor. Verify that ACIS SAT Files (*.sat) is selected as your Files of type. Click Open.

You will now notice that the fixture is mounted on your sink. If the fixture does not import into your sink family as shown, you will have to manipulate the placement of the fixture by going to the different views of your family and aligning the fixture to the correct side/face of the sink.

If you are satisfied with the results, then save your file with a new file name.

Warnings from the Bleeding Edge

Don’t say we didn’t warn you.  This is a fairly new workflow; not everyone has all the answers to this methodology of interoperability.  However, there are a few things to keep in mind.  When you import something modeled in Autodesk Inventor into Revit Architecture, the size of your family file (.RFA) will jump significantly.  The vanity sink without the modeled fixture is only 311KB.  Once the fixture is imported, the file size jumps to 1.1MB.  Considering that your file size on a simple family has tripled (in this case), where do you use this methodology?

Bringing Inventor geometry into a Revit family may serve its purpose for something as simple as a sink in a single family residential project highlighting the kitchen or a master bathroom.  However, using this same sink family within a 500+ unit hospitality or healthcare project can possibly degrade the performance of your overall Revit project.  As the designer, you will have to ultimately make this choice.  But as this tutorial has shown, it is certainly possible to model fixtures and other components with Autodesk Inventor and use them on your BIM project that is powered by Autodesk Revit Architecture.

About the Author

As a Technical Specialist, Micah Peterson provides training, consulting, and technical support for Microdesk clients nationwide. Micah possesses in-depth knowledge on a wide range of Autodesk applications and is adept at communicating technical information to Microdesk clients. By utilizing both his technical and sales skills he is able to ensure customers fully appreciate the advantages that come with a Microdesk partnership. Prior to joining Microdesk Micah spent 2 years in the United States Air Force before being honorably discharged and moving to an AutoCAD designer position at an audio/visual implementation company in Pensacola FL. More recently, he acquired a position as a Senior Applications Engineer where he instructed training classes and provided technical support for a local Autodesk reseller. He has expert level knowledge on AutoCAD, Revit, and Navisworks. Micah holds a Bachelors Degree in Computer Science from United States Air Force Academy in Colorado.  He can be reached at mpeterson@microdesk.com.

Shobhit Baadkar is Solutions Specialist, AEC, at Microdesk. He began using AutoCAD at an early age and was hired as CVIS’ seventh employee.  He was responsible for their expansion into the Los Angeles and San Francisco markets. He managed all strategy and innovation, as well as technical and training solutions throughout the company. During his final weeks at CVIS, he brokered the Microdesk acquisition of the CVIS commercial and government sales and technical teams. As a Solutions Specialist for Microdesk focusing on Architecture and MEP, Shobhit provides training, consulting, and technical support to Microdesk clients nationwide. Shobhit has trained and implemented hundreds of users operating various Autodesk AEC software applications. He is an Autodesk Implementation Certified Expert and has been invited to speak nationally at various professional organizations and universities throughout the country.  Shobhit holds a degree in Economics from University of California, Irvine.  He can be reached at sbaadkar@microdesk.com.

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