How to Add Center Marks in FreeCAD TechDraw

This guide explains how to place center marks on circles, arcs, and holes within the FreeCAD TechDraw workbench. You will learn the exact steps to apply center marks to individual circular geometries, configure their appearance, and adjust centerline extension lengths to conform to technical drawing standards.

Method 1: Using the "Add Centerline to Faces" Tool

The most direct way to create a standard crosshair center mark on a circular edge or cylindrical hole is with the face centerline tool.

  1. Open the TechDraw Page: Open your document and switch to the page containing the view with the holes or circles you wish to annotate.
  2. Select the Circular Edge or Face: Click on the circular edge or the cylindrical face of the hole in the drawing view. The selected feature will highlight (usually green).
  3. Apply the Center Mark: In the TechDraw toolbar, click the Add Centerline to Faces icon (a blue circle intersected by crosshair centerlines), or navigate to the menu: TechDraw > Centerlines > Add Centerline to Faces.
  4. Inspect the Result: TechDraw will generate a horizontal and vertical centerline intersecting at the center of the circle.

Method 2: Adding Centerlines Between Two Points or Lines

If your hole is shown in a side/section view rather than a top-down view, you will need a linear centerline rather than a crosshair.

  1. Select two parallel edges representing the diameter of the hole, or select two opposite vertices.
  2. Click Add 2-Line Centerline (for parallel edges) or Add 2-Point Centerline (for vertices) from the TechDraw toolbar.
  3. The centerline will appear halfway between the selected entities.

Adjusting Center Mark Properties

Once a center mark is placed, you can customize its dimensions and visibility in the Property View (Data tab):

  • ExtendBy: Determines how far the crosshair extends past the edge of the circle. Enter a measurement (e.g., 2 mm or 0.1 in) based on your drafting standard.
  • Style: Change the dash pattern from continuous to standard centerline patterns (e.g., DashDot).
  • Color and Weight: Modify the line thickness and color if your drawing requires different visual weights for annotations versus solid object boundaries.
  • Flip / Orientation: If the centerline appears rotated incorrectly, use the angle or orientation properties to align it with your drawing axis.

Removing or Modifying Center Marks

To delete a center mark, select it in the TechDraw tree view (listed under the parent View object as a CenterLine or Cosmetic feature) and press Delete. To refresh center marks after modifying the underlying 3D model, click the Redraw Page button in the TechDraw toolbar.