RFA & RVT Geometry Exchange Add-on for ARCHICAD 21AECbytes Tips and Tricks Issue #82 (March 21, 2018)

Link Ellis
ArchiCAD Technical Director, BIM6x


In December 2017, the new RFA & RVT Geometry Exchange add-on for ARCHICAD 21 was released by BIM6x. This free add-on enables ARCHICAD users to import RFA (Revit Families) into their ARCHICAD project as objects, including doors and windows.  It also enables the geometry exchange between Revit and ARCHICAD. In this article, I’ll discuss why it was created, what it’s good for, and how to get the most out of it.

Overview

Many ARCHICAD users, especially those in the US, are faced with the fact that most manufacturers’ content is available in Revit Family (RFA) format and not in native ARCHICAD GDL format. Even though GDL is a far more superior format in the sense that just one small file can contain an almost limitless combination of parameters and options, RFA is far more common. Therefore, a translator that can quickly and easily convert these files into ARCHICAD opens a whole new world of possibilities for including pre-made content into ARCHICAD projects. This is the most commonly used feature of the add-on.

The other most popular function is that it allows ARCHICAD projects to be quickly converted into Revit format. This allows users to quickly export their entire ARCHICAD model out into Revit format, which is proving to be a popular way to check and coordinate model geometry with consultants. Although not a replacement for IFC workflows, the RFA & RVT Geometry Exchange add-on offers another choice for interoperability for ARCHICAD users.

The add-on provides robust support in key workflow areas, which will be discussed in further detail in this article:

  • Importing 3D geometry from. rfa object files and creating GDL objects
  • Hotlinking 3D model geometry from. rvt project files
  • Exporting the 3D model geometry of ARCHICAD into .rvt format

Download and Installation

The add-on is available for both MAC and PC and can be downloaded from https://bim6x.com/store. It is downloaded as a zip file. To install it, close all instances of ARCHICAD 21 and run through the standard installation process. Once installed, be sure to check the Help menu > PDF Guides to access the Reference Guide for it.

ARCHICAD’s Add-on Manager shows details on where to find the function in the interface, but if you are using a customized work environment, then you may need to add these commands manually.


You can also create keyboard shortcuts or a toolbar, as shown in the following illustration. Create a New Toolbar, then from the List, select All commands by theme. Expand 17 Add-Ons > RFA & RVT Geometry Exchange. Select the two commands and hit the >>Add selected>> button to add them to your Toolbar. In ARCHICAD 21, right-click on your toolbar and select the toolbar from the context menu. Position as desired. Don't forget to redefine your Command Layout Scheme & Workspace Scheme in your Work Environment.



Functionality

The Add-on can perform three functions:

  • Import RFA as GDL Objects
  • Hotlink 3D RVT Model
  • Export 3D model as RVT Geometry

Import RFA as GDL Objects

If you want to test RFA files, we recommend grabbing some from bimobject.com. You’ll need to sign up with BIMobject to download them. For the following example, we are using the A. O. Smith_Horizontal Mount Commerical Storage Tank_HD.rfa

Once you have your RFA, go to File > Libraries and Objects > Import RFA as GDL Object. If different views of the object were saved in Revit, they will be available here. Often, there is just a View1 or default {3D} view. If you have the option, select View 1 to Define Import Geometry.


The next option is Import as Library Part Type. This allows you to bring in the object as an ARCHICAD Object, Door or Window. The default depends on which category it was saved as in Revit, but you can override it here if needed.


The final option is the Segmentation of Curved Geometry. This sets the facets of curved surfaces within the object. There are just three options. We recommend using the middle option, then adjusting if necessary, by re-importing the object.


Consider using the Polycount add-on to check differences between these settings.


All converted objects will go into the Embedded Library. If you add the same one multiple times (e.g., with different complexity) they will just get appended with a new number (1), (2), (3), etc.

One thing you may notice is that the Dimension settings are missing. This is because these objects are not currently scalable.


Some other options to note are:

  • Edge Snapping: This allows elements to be snapped to the object’s edges. This is more useful when importing RVT project files and then being able to snap to walls, slabs, roofs, etc., but it’s included here as well.
  • Rotation Angle: Sometimes elements come in on their sides, so this lets us rotate it back around the x axis and make it appear correctly. The options are 0 / 90 / 180 / 270 / Custom.
  • 2D Representation: Projection Line Pen is the pen that appears in plan.
  • Parts Visibility by Category: Elements can be assigned a category in Revit. These categories can be turned on and off here. An example may be a faucet on a sink.
  • Parameters: These parameters are greyed out as they can’t be changed, but they can be accessed in labels and schedules.

Hotlink 3D RVT Model

The add-on allows ARCHICAD users to hotlink an RVT, much like they would hotlink a PLN, MOD or IFC file. Autodesk provides Revit Sample Project Files on their website.

A new command is not created but when the Place Hotlink command is invoked, RVT will be a new option.


ARCHICAD 21, in general, does not create stories when placing any type of hotlinked modules. In keeping with that, you will need to create these before or after the hotlink is placed to see the entire RVT model. Specifically, just the number of stories need to match, not the names or even the heights.



The Hotlink RVT 3D Geometry dialog offers the following options:

  • Import element Parameters and Categories: Uncheck if you are not concerned about any data whatsoever. Otherwise this option will create a group of parameters or a system of classifications with the prefix you give it here.
  • Building Materials and Surfaces: Import them all with a prefix or choose one building material in the host file for all. All Building Materials will have their Cut Fills set to Air Space since everything is converted to an object and is hollow anyway. Intersection Priorities of Building Materials are all set to 0 for the same reason. Surfaces of Building Materials will have no texture images as they are not yet supported.
  • Layers: Import them all with an extension or choose one layer that you can create on the fly. A new layer will have intersection priority of 0 and be turned off in all layer combos.

Once hotlinked, the RVT module cannot be edited, just like any other hotlinked module. It can be updated, but the Hotlink RVT 3D Geometry dialog will always reappear for new elements. Updating will not replace or delete any attributes that have been added already.

Export as RVT 3D Geometry

The add-on provides the functionality to export the 3D geometry as an RVT file. Keep in mind that this should just be used for quick checks for collision detection or model checking. For detailed conversion to Revit, we strongly advise using IFC workflows.

To export your 3D model, first open the 3D Window Open and adjust to prepare for export. All view settings are exported, except Graphic Overrides. Then go to File > Interoperability > Export as RVT 3D Geometry.  Export is generally very simple with just a few options to decide on:

  • Export Classifications and Properties: Uncheck if you are not concerned about any data whatsoever. Otherwise this option will create a classification and properties based on the ARCHICAD Classification selected, or all properties and classifications.
  • Keep Curtain Walls, Stairs and Railings as single elements: Uncheck to export these as hierarchical sets of elements in Revit.
  • Units: Select from Imperial or Metric.

The export process generally only takes a few minutes and the project can be opened directly in Revit without any further conversion. The add-on currently only supports up to Revit 2017, so the project may be automatically updated once opened in Revit. It should be noted that 2D data is not converted during this process, but Revit Interference checking can be applied immediately.



If you have any further questions, please refer to the RFA and RVT Geometry Exchange Add-On for AC21 PDF. There are also many questions answered on the FAQ page.

A reminder that the add-on is free and can be downloaded from BIM6x.com/solutions.

About the Author

Link Ellis, formerly of ArchiLINK, is now the ARCHICAD Technical Director at BIM6x. Link is a passionate BIM implementer, specializing in ARCHICAD training and templates. With over 19 years in the industry, he has extensive experience and knowledge of ARCHICAD. Clients have requested his services across the globe including in the USA, Canada, UK, New Zealand, Australia, India, and the Middle East. Link has a long-standing relationship with Graphisoft's ARCHICAD development team and communicates with their technical support team regularly. He is also an award-winning ARCHICAD alpha and beta tester since 2003, member of multiple ARCHICAD forums, and a highly respected and well-liked member of the ARCHICAD community.

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