Unable to change CAD line widths in ArcGIS Pro

Description

When a CAD (.dwg) file is used in ArcGIS Pro, line widths appear thick or thin, and the width units cannot be modified. The map shows no change in line appearance even after increasing the line width in the Symbology pane, although the Contents pane displays a thicker line symbol.

Cause

This behavior is due to the way ArcGIS Pro renders CAD (.dwg) data. When a CAD (.dwg) layer is symbolized using Unique Values, ArcGIS Pro honors the CAD feature properties. As a result, the line width and width unit cannot be modified directly in the Symbology pane.

Solution or Workaround

Depending on the preference for single symbol or unique values symbology, use one of the following workflows:

Remove the size variable that inherits the CAD feature properties

1. Open the project in ArcGIS Pro.
2. Select the feature layer with the unique values symbology and open the Symbology pane. Refer to Steps 1 through 3 in ArcGIS Pro: Set the size variable to a field or an expression for instructions. In this example, Polyline is selected.
3. For Field, click the drop-down menu and select <None>. This removes the size variable that controls the line width based on the inherited feature properties and allows the symbol size to be changed.

4. In the Contents pane, click the line symbol to modify, and change the Line width parameter in the Symbology pane.
5. Click Apply.

The map below displays a DWG dataset in which one of the lines has increased thickness.

Change symbology to single symbol

1. Open the project in ArcGIS Pro.
2. Change the symbology from Unique Values to Single Symbol, and modify the line width of the symbol. Refer to Steps 1 through 3 in ArcGIS Pro: Single symbol for instructions. In this example, the Polyline layer is selected in the Contents pane.
3. Click the symbol to modify the symbol properties. In this example, on the Properties tab of the Symbology pane, Black is selected for Color, and 2 pt is specified for Line width.

The map below displays the DWG dataset using single symbol symbology with an increased line thickness.

Note: 
If necessary, change Primary symbology back to Unique Values and re-configure the symbology fields before editing the line width for the individual lines.

Use the Buffer tool for unique values symbology

1. Open the project in ArcGIS Pro.
2. On the Analysis tab, in the Geoprocessing group, click Tools to open the Geoprocessing pane. Search for and run the Buffer (Analysis Tools) tool to create a buffer that uniformly increases the line width. In this example, for Input Features, Polyline is selected. For Output Feature Class, the name is specified as Polyline_Buffer. For Distance [value or field], 3 is specified, and for Linear Unit, US Survey Feet is selected.

3. In the Contents pane, right-click the buffer layer and select Symbology.
4. Apply Unique Values symbology to the buffer layer. In this example, Layer is selected for Field 1, and Basic Random is selected for Color scheme.
5. Click Color scheme options and select the preferred color scheme. In this example, Apply to fill and outline is selected.

6. Click Close.

The map below displays the DWG dataset using unique values symbology with an increased line thickness.