Back to Basics with Revit Walls Part 3: Bringing It All Together

Posted on December 31, 2014 by Bill Knittle, Synergis Building Solutions Engineer:
In some cases, our walls need to follow even more elaborate construction techniques. In this case, we’re going to look at how to create a foundation wall with an accurately modeled brick ledge or shelf.
To begin this process, let’s take a look at the exterior wall’s assembly in section. It has a Layer that has been split into two regions whereby the bottom region is brick. In order to create a brick ledge, we’ll need to unlock the Layers 1 and 3. This is accomplished by selecting the Modify button at the base of the dialog and selecting the bottom line of each of those Layers. It is very important that the Layers being unlocked be adjacent to one another. Revit will not allow the Layers to be unlocked if there are locked Layers in between them.
By unlocking the lower lines of the Layers, it unlocks an Instance parameter called the Base Extension Distance. Like the Base Offset, this parameter will raise or lower only those Layers that were unlocked in the Assembly of the wall. There is also a Top Extension Distance parameter should the upper lines of Layers be unlocked within the Assembly of the wall.
In this example, we’ll lower the Base Extension Distance 8”.
As we take a look at a section view through the walls, we notice that there is an overlap that occurs. This is where some of the things we learned in Part 2 come in to play. To resolve this issue, we’re going to resort to the Join Geometry tool. The exterior wall is selected first and the foundation wall is selected second. The end result is a 6” deep brick ledge.
This is accurately represented in the model now. However, there are still some issues to resolve. The brick ledge is not consistent at the corners of the foundation walls. This is evident when the foundation walls are isolated. The solution is to join the geometry of each exterior wall to the adjacent foundation wall and not just the one underneath it.
The additional joins eliminates the unwanted geometry where the brick ledge should turn the corners.
One last enhancement that can be made is to step the brick ledge by modifying the exterior wall’s profile. When finished, the joined walls immediately regenerate with the intended results.
Hopefully, you’ve found these basic wall techniques helpful and in creating a more reliable model in the future.
See Part 1 or Part 2 of this series.
Happy Designing,
Bill Knittle
See some of Bill’s other posts:

• Using Parts in Autodesk Revit
• How to Build Your Own Roof Truss Families
• SET’g the Stage in Autodesk® Navisworks®
• Revit Tip:  Worksharing between Revit and Revit LT
• Revit Tech Tip 26:  Construction Modeling and Phasing

For the past seven years at Synergis, Bill has been training, supporting, and implementing the Building Solutions offered from Autodesk, primarily the Revit applications. His accomplishments include many certifications which include AutoCAD, AutoCAD Architecture, and Revit Architecture. He is also an Implementation Certified Expert for Revit Architecture and Structure. Bill’s latest achievement was acquiring the MEP Systems Specialist certification from Autodesk which has propelled Synergis as a Platinum Service Provider. Bill’s interactions with customers have provided him with constant challenges that lead him to think outside the box.  As a result, he has authored several technical solutions for publications which include AEC Bytes and Cadalyst as well as, produced several tips and tricks videos for the Synergis Website and You Tube channel. He enjoys consulting with a many different Architectural or Engineering firms struggling to implement the BIM process using the Revit application.  Bill has been certified many times on Autodesk products, including Revit Architecture, Revit Structure, AutoCAD , and AutoCAD Architecture.
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