Revit Adaptive Components for MEP

August 30th, 2013

The initial release of Autodesk® Revit® (Architectural Design) and its early adoption by the architecture industry has afforded architects the ability to effectively utilize specialized features and functions over the platform’s continued evolution. Over the years, Revit has released additional versions that focus on specific disciplines and workflows (i.e., MEP Engineering and Structural Engineering). As these disciplines have adopted the platform and its features into their workflow, the opportunity to utilize the features offered in other versions of Revit were not easily accessible or even thought to be beneficial—until now.
Autodesk Revit is now an application that combines the capabilities and features of all its Revit releases (Architecture, MEP, and Structure). As designers and technologists, we found an opportunity to research and experiment with features that yield useful results in efficiently managing MEP workflows.

A feature architects are utilizing is the Conceptual Massing Environment as well as the use of Adaptive Components within this environment. Adaptive Components offer a high level of flexibility that allows the application to accommodate certain circumstances that the normal modeling tools would typically make difficult. With the introduction of Revit “One Box,” the flexibility of these tools can be applied to the MEP side to tackle difficult design constraints as well as advanced uses of parametric control.

Features of Adaptive Components

Most components in Revit look to the active set work plane. Adaptive Components use what is referred to as “3D-Snapping” and can host on alternate surfaces without having to change the active work plane. They have a set number of host points that allow them to be flexible per the design and complexity of the component.

Uses for Architecture

Adaptive Components are rapidly increasing in use among architectural modelers. This feature was found to be effective in patch and repair scenarios on complex curtain walls. To use them as a typical panel requires an excessive amount of manual production work. With the release of Revit 2013, the new Repeat tool has enhanced the credibility of Adaptive Components, especially in façade panelization.

However, apart from surface panelization, Adaptive Components are now often used for railings, mechanical and electrical fixtures, and an array of other purposes. Its flexibility to react to multiple host surfaces has opened avenues for exploration in generating iterative design workflows.

Scenarios for MEP

At a recent conference, we demonstrated two scenarios that applied the use of adaptive points in MEP families. The first addressed complex architectural geometry—more specifically, hosting and adapting to changes in curved surfaces. The second made use of reference grids and advanced parametrics and logic for the automated placement of terminal components such as sprinkler heads.

Scenario One

This workflow was developed during a project where the modeling of fire protection and mechanical ductwork required the sprinkler heads and air terminals to be positioned normal to double curved walls and ceilings. Placements were determined from drawings provided by MEP consultants by way of reflected ceiling drawings. The task was to project those location points up to the double curved surfaces. Not only did these points need to be located correctly on those surfaces, they had to be flexible as updates to their placement arrived on a weekly basis by the consultant.

The Revit components included the fire sprinkler heads and air terminal families, which were generated from generic model templates. These families were established in order to control the correct sizes of components through parameters.

For hosting purposes, these families were nested inside face-based templates. This enabled their placement on any given surface even though their ability to be updated was limited due to a lack of strong placement points. Additionally, the Revit MEP Connect Into feature did not work properly with simple face-based families, as these face-based families would reference the level they were associated with rather than the offset from that level. This is where the value of the Adaptive Component emerges. By nesting the face-based families into an Adaptive Component and hosting it on an adaptive point, MEP systems will recognize the physical location in the space rather than any particular level with which they may be associated.

Figure 1: Example of curved architectural massing

To highlight areas of skepticism, many will note the inability to connect systems to nested families. With this described method, it is now possible. By using the Tab key a user can locate the connector and “Connect Into” the desired path.
In order to update the workflow, the Adaptive Component needs to take advantage of the In-Place Massing environment. After creating an In-Place Mass, the user will need to divide the surface. Once a desired surface is selected, this feature becomes available within the massing environment and creates a UV grid that conforms to the complex surface.

For the MEP user to drive the placement of the surface-based family from the active working plane, they will need to project the locations from that plane up to the complex surface. The next step is to create perpendicular reference lines, which create intersections at each head location on the active workplane (where the linked CAD MEP placement drawing is hosted). This step is critical in order to create placement points for the desired sprinkler head or air terminal directly above the divided surfaces.

In order to project these intersections onto the surface of the mass, one needs to first turn off the UV grid pattern and instead choose the Intersect option for generating the divided pattern. Finally, nodes must be turned on for the divided surface, which will create a placement point for the Adaptive Components. With nodes visible, the custom Adaptive Component of either the sprinkler or the air terminal can be placed on the projected nodes. If the head is to be repeated across the points, the user can take advantage of the Repeat tool after the initial adaptive component has been placed.

When these steps are carried out, connections may be made to the heads and the systems tested. When an update arrives, the intersecting reference lines will need to be relocated to the newly provided locations. Simultaneously, the projected point locations on the complex surface will automatically update. 

Figure 2: Air terminals hosted to architectural massing using adaptive components

Scenario Two

The second scenario is one that would appeal to fire protection engineers, but the concept is certainly applicable to many of the building services disciplines. In this scenario we use the same concept of the adaptive terminal family from the previous scenario, but this time in conjunction with another architectural feature called Divided Surfaces.

Divided Surfaces works with the massing environment that we have already covered. What it does for our purposes is to essentially provide an adaptive analytical grid that is associated with a plane—in this case the ceiling plane that will host our sprinkler heads. The grid is parametric and adaptive so it allows the user to control the grid spacing and intersections, where it can adapt to the changes of the hosted surface. As an example, if a user defines certain constraints related to the spacing of sprinkler heads, such as code requirements, and the underlying size or shape of the ceiling changed, the grid can react to those changes.

So we have talked about the Divided Surface grid up to this point. Here is where it gets fun. The Divided Surface intersections that have been defined can be used to automatically place all the sprinkler heads because they were created using Adaptive Components. As the underlying surface changes or the parametrics of the grid change to adjust to the various constraints, the sprinkler heads now have the intelligence to update accordingly based on the changing intersections.

Figure 3: Sprinkler head family adapting to divided surface grid intersections

Setting Up Your Content

Since the scenarios we tested focused on face-based terminal devices, we will refer to them as the default scenario moving forward. For the most part, little changes will be made when it comes to the MEP content. All the existing terminal devices that exist in the user’s library will work under the scenarios outlined here. Essentially, there is no reason that any device used in the past cannot be adapted in the ways we have outlined. Here is a brief rundown of the steps involved.

  • Have a working MEP terminal family ready to go, or create one using your company’s standard methods.
  • Create a new instance of a Generic Model Adaptive family.
  • Create at least one adaptive point.
  • Set the required parameters or constraints for the point.
  • Load the MEP family into the Generic Model Family, hosting it as desired.
  • Save this completed family to be loaded into the project.

Now that there is an understanding of the steps involved, we will walk through each one.

Figure 4: Air terminal family nested inside an Adaptive Component family

MEP Family Behavior

One of the interesting aspects of these techniques is that due to the nature of the platform, we must load these adaptive families under the dreaded Generic Model category. As a result, it presents a host of questions and issues about how this might affect scheduling, visibility graphics settings, as well as integration with MEP systems and their associated flow calculations.

Our initial concern was that all these scenarios would not only prove to be difficult to address and result in a failed outcome but that it would ultimately be detrimental to our project and negate any benefits that we may have seen. As long as the nested MEP family is properly categorized and fully functional, even though it is nested inside of a Generic Model family, it will integrate into the model as expected. This is to say that it schedules properly, becomes hidden when toggling the visibility graphics override (in this case Air Terminal), the filters recognize it, and it can work as part of a system.

Integration with Systems

Out of all of these scenarios outlined in the previous section, the only one requiring some explanation is integration with systems. Since these terminal families are nested at least one level deep in a generic model, and in some cases two levels deep if inside an in-place mass, the user must appropriately highlight the element. The way to do this is to use the tab button to go deeper into the selection level. This is standard practice for many scenarios, though it is not usually employed in this manner. For example, to properly select one of the air terminals to change the airflow parameter or to highlight the connector, the user must tab through the desired number of levels, usually once or twice, before using the left mouse button to make the selection. One can always check if the proper family is selected by verifying its name and category in the Properties window.

When it comes to connecting duct or pipes, the workflow may differ slightly. To use ductwork as an example, it is possible the air terminal will not show the connector as anticipated. The best approach we have developed to make this work successfully is to start the initial run of duct upstream of the terminal, and then make the final connection at the terminal itself. When hovering over the connector area, a snap indicator should appear, allowing the user to make the final connection to the terminal. Because the use case for air terminals is in hosted scenarios that require relocation and adaptation to design changes, we have found that the flex duct works well when the locations of air terminals move. In the case of sprinklers, layouts may need to be fairly complete prior to making the final pipe connections. We have had favorable results using the “Connect Into” feature to make the final connections to sprinkler mains with adaptive families.

Mark Green is the Director of Digital Engineering at Oldcastle BuildingEnvelope®. He leads efforts to leverage the potential of BIM in Architecture/ Engineering/Construction (AEC) design-to-fabrication practices. Mark holds a Master of Architecture, from Columbia University and a Bachelor of Science in Architectural Studies from the University of Utah, graduating summa cum laude. Mark is also a candidate for Doctor of Education (Ed.D) from Teachers College at Columbia University. He is an adjunct Professor at the GSAPP and the University of Utah’s College of Architecture + Planning. Mark resides in New York City.

Alan Jackson is a Senior Design Technology Specialist at CASE and specializes in MEP engineering and consulting. Alan’s passion for sustainability, master planning, and energy performance analysis has translated to an interest in utilizing energy modeling platforms and related analysis tools to address and improve building performance.

 

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