Overview

When exporting layout data from CST Studio Suite—such as Gerber or DXF files—it is important to understand how CST handles coordinate systems during the export process. A common source of confusion occurs when the 2D CAD export options (DXF and Gerber) appear grayed out, or when the intended layer cannot be selected, even though the geometry is clearly visible in the 3D view.

This article explains why this behavior occurs and demonstrates a simple, reliable workflow to ensure your layers are exported correctly by properly using the Working Coordinate System (WCS).

Why Does This Issue Occur?

By default, CST exports Gerber and DXF data relative to the global coordinate system, assuming that the geometry to be exported lies exactly on the plane:

Z = 0

If a layout layer is even slightly offset in the Z-direction, CST may still display it correctly in the modeler. However, during the export process, CST does not recognize the layer as valid 2D geometry for export.

As a result, you may observe the following behavior:

• The DXF and Gerber options under 2D CAD appear grayed out
• The intended layer cannot be selected for export

This situation commonly occurs when:

• The layer is at a non-zero Z location
• Multiple coordinate systems were used during modeling
• Geometry was imported from another tool with different reference planes

Recommended Solution: Align the Working Coordinate System (WCS)

Activate the Working Coordinate System (WCS), so the solution will be straightforward:

Align the WCS to the layer you want to export before starting the Gerber or DXF export process.

Once the WCS is aligned, CST treats the WCS reference plane as the export plane, regardless of the layer’s position in the global coordinate system. This enables the layer to be recognized correctly during export.

Step-by-Step Workflow

1. Identify the Layer to Export

• Select or visually confirm the layer or sheet you want to export
• Check its position relative to the global Z-axis
• Confirm whether the layer lies on Z = 0 or is offset

2. Align the WCS to the Layer

1. Activate the Working Coordinate System
2. Use one of the following alignment methods:
   • Align the WCS to a face
   • Align the WCS to a picked planar object
   • Manually define the WCS origin and normal direction

Ensure that:

• The WCS U–V plane coincides with the layer
• The layer lies at WCS W = 0

This step is critical, as CST will use the WCS plane as the reference for the 2D export.

3. Start the Export Process

• Navigate to:
  Modeling → Import/Export → Export 2D Files
• Choose the appropriate format:
  • DXF for mechanical or layout exchange
  • Gerber for PCB or manufacturing workflows
• Verify that the intended layer is now active and selectable

4. Export the File

• Complete the export using your desired settings
• The exported file will now correctly include the selected layer geometry and positioning

Video Example: DXF Layer Export Using WCS

To demonstrate this workflow, a short video example is attached to this article to show:

• How to align the Working Coordinate System to a layer
• How the layer becomes active after WCS alignment
• How to export the layer as a DXF file

✅ Note:
The workflow shown in the video for DXF export is essentially identical when exporting Gerber files. In both cases, the key requirement is ensuring the WCS is properly aligned before starting the export.