A fiducial is a centering mark. It is used to center different films and layer masks over each other within the manufacturing process. Often there are used more than one of them in one layout.

You can reach this mode...
by "Place Centering Marks (Fiducials)" in Menu Elements or
by the tools Fiducials.jpg Find them under button Pen.jpg

Leave this mode...
by [ESC] or M12

Fiducials .jpg

What you can do...
Press [o] (for options) to edit settings (form and the radius) before you place the fiducial by M1. After you have placed a fiducial you can edit it by M11 and the dialog that follows.

You can select from the following forms:

Fiducial3.jpg Target: A fiducials like this is made of concentric circles and a central cross.
Fiducial2.jpg Arrow: A circle with an arrow in the center. This fiducial also informs about the placement direction.
Fiducial1.jpg Two quarters: This fiducials can be placed and turned at 90° against each other. When films do exactly match, a full circle can be seen (without gap) when looking against the light.
Fiducial0.jpg Full circle: You also might use a filled slice as a fiducial.

The line width defines the width of the line that is used to draw the fiducial. The direction parameter is used to define the angle on which the fiducial is rotated around its center. Also, you define the layers on the PCB on which this and future fiducials should appear.

Free the fiducial of solder resist

Click M11 on the fiducial, enter to the dialog (since V30)

Passermarke fre ei.jpg
Image: Free the fiducial of solder resist, expand it if neccessary