Create a Revit Site Model by Linking CADMapper

By Jon Henning •  Updated: 10/27/19 •  6 min read

This tutorial highlights the importance of a “Linking” workflow between AutoCAD and Revit.

This workflow is useful for keeping file sizes smaller, and to encourage a better system of file organization. Many design programs have “linking” capabilities (Adobe InDesign, Illustrator, Premiere Pro, etc.), so it’s very helpful to understand how this process works to allow for greater integration of software tools throughout the design process.

Through a system of linking, we have the potential to make our entire digital design process coherent, organized, and systematic. This is vital for saving time.

If you aren’t already following along, be sure to check out my last two CADMapper tutorials. I walk through how to get to this stage of the process in less than 15 minutes of total video content. These tutorials are located here:

Tutorial #1: Create a 3D Site Plan Using CADMapper and AutoCAD

Tutorial #2: How to Create Revit Topography from a CADMapper File in 3 Minutes


The Linking Workflow: Save time, and create Detailed Revit Site Models

Time saved drafting, is time spent designing. We strive to become better designers, so it’s imperative to learn how to use these digital tools to make our entire process more efficient.

Here’s how to use the process of AutoCAD “Linking” to quickly create detailed site plans in Revit Architecture.

Use the “CAD LINK” Tool to Attach AutoCAD .dwg Files to Revit

Open up your Revit project file. If you are following along with my last tutorial, you should open the topography file that we created. Under the “Insert” Tab, select “Link CAD”. This option is similar to how XREFs work in AutoCAD, and this system has many benefits that can make your entire 3D modeling workflow more efficient.

Create a Revit Site Model by Linking CADMapper
Create a Revit Site Model by Linking CADMapper

Go through and be sure to link all of the necessary .dwg files to be shown on the Revit Model.

Create a Revit Site Model by Linking CADMapper

IMPORTANT: I did not mention this in the video tutorial, but there is an issue that some people are experiencing with Revit and AutoCAD links which causes overlaid XREFs to display in Revit, resulting in duplicate information. This problem shows up after closing and re-opening the project. To prevent this, simply change the “Layers/Level” import option to “Visible”. This will prevent overlaid XRefs in AutoCAD to display as duplicate information in the Revit model.

Use XREF “Overlays” For drawing clarity

Back in AutoCAD, we want to set our file up to accommodate any potential changes that we may need to make in the future. By using a system of XRefs attached as “Overlay” files, we combine all of the information we need into one model to allow for greater clarity and ease of editing.

“Overlay” is a tool that allows information to be displayed from other models/drawings, but it prevents this information from being edited directly from within a specific file. For example, say we have the ‘Building’ file open. We can “Overlay” the ‘Roads’ file so that the roads show up in the ‘Buildings’ file, however it will not be possible to edit the roads directly within the ‘Building’ file. The “Overlay” is extremely useful for three reasons:

  1. It prevents us from accidentally making edits to other .dwg geometry.
  2. Geometry does NOT have to be duplicated (copied from drawing to drawing), therefore decreasing overall file size.
  3. It is a system of ‘linking’ that most modern design programs utilize (all of Adobe’s graphic design software utilizes linking). It’s important to get in this workflow mindset to become more efficient designers.

Open the “Buildings” .dwg file. Use command “XA” (Attach External Reference), and select any of the .dwg files we created to link back to the “Buildings” file. Ideally, you’ll want to overlay all of the .dwg files to show all of the information.

Be sure to double-check that the scale factor is 1.0 (which is 1:1 scale), and select “Overlay” as the ‘Reference Type’. Unlike “Attachments”, Overlaid files are ignored when the current drawing (“Buildings”) is attached to another drawing. We will be attaching the “Buildings” drawing to our other .dwg files, so it is important that you select “Overlay” and not “Attachment”.

Once all of the .dwg files have been externally referenced as “Overlay” files, the model should look similar to this:

Making changes to the linked .dwg files to reflect in the Revit model

Since we’re linking all of the .dwg drawings to Revit, changes to any model space elements (buildings, roads, etc.) can ONLY be made in the original AutoCAD file. CADMapper does a fine job at providing a lot of information, but sometimes we need to make changes to site plans throughout the design process. Changes to topography can be made natively in Revit, but changes to roads and existing buildings must be made in the individual AutoCAD files that we created.

For example, say that this building needs to shift along the y-axis. We can make this change in AutoCAD, and save the drawing once the changes are made. We will notice that if we have other AutoCAD drawings open, and the ‘Building’ drawing is attached as an “Overlay”, AutoCAD will prompt us that changes have been made and we need to reload the file.

It’s important to understand that this type of workflow often requires constant “reloading” of information. When changes are made (and they can be made by other people working on these drawings), they need to reflect on all drawings for consistency purposes.

To reflect this change in Revit, however, requires a couple additional steps.

In Revit, navigate to the “Manage” tab. Select the “Manage Links” option and select the “CAD Formats” tab. All files attached using the “Link CAD” will exist on this list.

To update changes made in the AutoCAD drawings, select the “Link Name”, and ‘Reload’. Hit apply, and the changes will reflect on the Revit model.

…and that’s all! Great job for making it this far, and hopefully this method will save you hours of time creating 3D sites.

If you found these tutorials helpful, please let me know on social media. Your feedback is really important to me, and I’d love to hear what other types of tutorials you would be interested in.

Continue this tutorial series, here:

👈 Previous Tutorial, #1: Create a 3D Site Plan Using CADMapper and AutoCAD

👈 Previous Tutorial, #2: How to Create Revit Topography from a CADMapper File in 3 Minutes

Jon Henning

Hi, I'm Jon. I write about emerging technology in architecture, engineering and design, and I want to help you push boundaries with the latest tech trends in the AEC industry.

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