mairomaster , 04-14-2016, 12:30 PM
For the keepout region you need it to be a filled circle which covers the fiducials and solder mask expansion. However, in Altium you can't draw a filled circle so you have to cheat it. You can draw an arc, which is a part of a circle with parameters angle, radius and width of the line. To make a full filled circle, you need to make the arc 360 degrees, give it a radius of D/4 (D is the diameter of the filled circle you need) and give it a line width of D/2. Arc is one of the standard drawing elements available from the Place menu. Here is an example of a keep-out region used for the fiducial (the diameter in the example is 10mm because it is just an example, with the actual fiducial I am using 3mm):
Play around with drawing arcs and you will get what I mean.