ArcGIS Pro

ArcGIS Pro symbology for the Civil 3D objects: working with LYRX files

Autodesk Civil 3D entities are supported in ArcGIS Pro 2.6 and later. These entities are added to ArcGIS Pro with an advanced symbology. Arcade scripting is used to mimic the default styles in Autodesk Civil 3D.


Advanced symbology examples: The red hatching depicts a site and within the parcels. In purple, you can see an annotated sanitary network (pipes and structure); in blue, an annotated storm network (with pipes, structures, and inlets); in light blue, an annotated pressure network with fittings and appurtenances. And in the center of the street is an alignment with stationing annotation every 10 meters.

This advanced symbology is applied automatically when Civil 3D entities are added to a map or scene in ArcGIS Pro. The predefined symbology for these entities is stored in LYRX files that are read when the layer is added. These LYRX files can be modified to customize symbology that follows the standards of your organization, ensuring consistency.


LYRX files

LYRX is a file format created to save and share feature layer definitions.

The LYRX files used by ArcGIS Pro for Civil 3D symbology are found in this location by default:

C:\Program Files\ArcGIS\Pro\Resources\ArcToolBox\Templates\Layers

These files are read automatically and applied for each different entity type. The name of the LYRX file dictates which file is used for the matching entity type, where the LYRX file is prepended with the label “CAD_” followed by the name of the Civil 3D entity type.

For instance, the CAD_Alignment.lyrx file is used to upload the predefined symbology for the alignments into a map; whereas the CAD_Alignment_3D.lyrx file is used to upload the predefined symbology for the alignments into a scene.

Listed below are the files installed by default. If you remove them from that location, ArcGIS Pro will apply a simple default symbology, which will be based on the graphic properties of the AutoCAD layers where those entities are found in Autodesk Civil 3D.

In the same way, if you replace any of these files with your own symbology definition, the new symbology definition will be applied the next time that this Autodesk Civil 3D entity is added to ArcGIS Pro.

Customize a feature layer symbology and set it as the default

The following steps describe how to change the current symbology and save it in a .lyrx file, so the next time that a new entity of that type is loaded, it will use the modified symbology.

This example will show how to change the distance between the stations in the Alignment feature layer, from 10 meters to 15 meters. In addition, you will change the mask of the station, from having two digits (for example, 14+30) to three digits (for example, 1+430) after the plus sign.

This change can be made to the symbology of the Alignment and Alignment Profile, for either maps or scenes. In the following section, I will also show how to save changes that you make to an LYRX file to reuse and share your changes.

The symbology uses the m-value of these feature classes to position the stations along the alignment.

Note: These two changes can easily be required by different groups of engineers.

Change the intervals between stations

These steps describe how to change the interval of the station from 10 to 15 meters.

Another way to do so is to right-click the Alignment feature layer and select Symbology.

This will open a code editor from where you need to change a value.


Note: In Autodesk Civil 3D, the default symbology for the alignments renders those with the Offset type without the station, and that is what we are doing here. If the alignment is Offset, it takes the default value of 0, which means no stations will be rendered.

Change the stations mask from ###00+00.## to ###0+000.##

These steps describe how to move the plus sign to the left and leave three digits to the right.


There are functions used to build the mask for the $measure value.

Currently, the generated mask looks like this: ###00+00.##

Saving the changes and set them as the default symbology

After performing changes to the symbology, they will apply only to the feature layer where you made them. You can make these changes available to be used for other alignments, and they can also become the new default symbology when new alignments are added to the map or other maps.

To do this, you need to save the feature layer definition as a LYRX file.

Now that you have the symbology changes saved in a file, you can apply this symbology manually to a feature layer, or you can use this file to overwrite the default symbology definition of ArcGIS Pro for the corresponding Civil 3D entity type.


Applying the LYRX file with the symbology manually

To apply the LYRX file to a specific feature layer, do the following:

This will launch the Apply Symbology From Layer geoprocessing tool.

When the tool finishes running, the symbology will be updated in the map.



Apply the LYRX file with the symbology as the new default

To apply the LYRX file as the new default symbology for a specific type of Civil 3D entity, you need to replace the out-of-the-box file with the new one in this folder.

C:\Program Files\ArcGIS\Pro\Resources\ArcToolBox\Templates\Layers

You need to follow the naming convention so the file will be taken by ArcGIS Pro the next time that is needed.

Review the LYRX Files section.

For your example, you need to rename the file to CAD_Alignment.lyrx.

It is a good practice to keep a copy of both the new and the original LYRX files.

If you have customized one or more LYRX files, and later you uninstall ArcGIS Pro, the file with the custom symbology will be uninstalled. And the next time you install ArcGIS Pro, the default symbology will be used. So, you will need to apply your file to that directory again to apply your custom symbology.

About the author

Richard Horrocks

Richard is a Product Engineer for AEC at Esri located in Ottawa, Ontario. He enjoys improving workflows for the integration with the Architecture, Engineering and Construction (AEC) industry.

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