What is ʼCenter Markʼ and ʼCenterlineʼ in SolidWorks?

ByCADbrief Staff

Short Answer

In SolidWorks, Center Mark and Centerline are drawing annotation tools used to identify circular features and define axes or symmetry references. The most common professional method is adding them from the Annotations toolbar in a drawing view. One limitation is that they depend on valid model geometry and view orientation.

What You Need to Know Before

Warning: center marks and centerlines in SolidWorks often fail or become detached when drawing views are broken, imported, or based on incomplete cylindrical geometry. If the source edges are not recognized as circles, arcs, or aligned model references, the annotation may not place correctly.

How to Add Center Mark or Centerline

  • Command: Center Mark / Centerline

  • Shortcut: [No default keyboard shortcut]

  • Quick Steps:

    1. In a drawing, go to the Annotations toolbar or Insert > Annotations and choose Center Mark or Centerline.
    2. Click the circular edge, arc, slot, or two aligned edges in the drawing view.
    3. In the PropertyManager, enable a real option such as Auto insert on view creation or adjust extension size/gap if needed, then confirm the annotation.

Variables & Settings

  • Key Setting: Document Properties > Detailing > Centerlines/Center Marks

  • Expert Setting: This controls display behavior such as center mark size, extension lines, gap, and automatic insertion rules. If these values are too small or disabled, center marks and centerlines may appear missing even though they were created.

Why it Fails

  • Cause 1 (Geometry): the selected entity is not a true circular edge, arc, or valid linear reference, so SolidWorks cannot generate a center mark or centerline.
  • Cause 2 (layers/Locks): the annotation layer may be hidden, non-printing, or controlled by drawing settings that suppress visibility.
  • Cause 3 (Command/Logic): auto insertion may be turned off, or the drawing view type does not support the expected annotation behavior.

Quick Fix & Best Practice

  • Quick Fix: open Document Properties > Detailing > Centerlines/Center Marks and increase size/visibility settings, then reinsert using Insert > Annotations > Center Mark or Centerline.
  • Manager’s Verdict: use center marks for holes and round features, and centerlines for symmetry, axes, and manufacturing clarity. Avoid relying only on auto insertion for critical production drawings.

FAQ

What is the difference between Center Mark and Centerline in SolidWorks?

A center mark identifies the center of a circular feature, while a centerline shows an axis or symmetrical reference.

Can SolidWorks add center marks automatically?

Yes, if automatic insertion is enabled in drawing document properties.

Why is my centerline not showing in the drawing?

The geometry may be invalid, the annotation style may be too small, or the layer/display settings may be hiding it.

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