Reference Point Symbol Rules

Hi,

I am trying to determine the name of and rules for the Reference Point Origin Designator.

It looks like this:

http://img444.imageshack.us/img444/3104/origin.gif

What are the rules for using it and what part of the circle is shaded?

I am not sure if there is any specific rules for use, Fanuc programming manuals generally use the one you show to indicate the Work coordinate ref points G54-G59 etc, except the opposite quadrants to the one shown are shaded.
Fanuc designation show the Machine origin a bit different with an inner circle with the top left quadrant of the inner circle only shaded.
If you have access to a Fanuc programming manual it could help show it, I also have some CNC programming manuals that indicate the same for the most part, with a few minor differences.
Al.

The symbol you have shown is called the Datum Target.

Part Orientation to Datum Planes as established by Points, Lines or Areas.

Check out this site: http://www.engineersedge.com/gdt.htm

Scroll down to the definitions and you will see several ones for the Datum.

Kenny :)