Development: Addon Similar to Blizz Raid Marking
 

I am trying to build an addon similar to the current raid marking system for myself and a few friends. Basically, we always get split up in Wintergrasp (various raid groups) or none of us get lucky enough for leader in Alterac Valley, and we enjoy the special teams surgical strike mess. Trying to build an addon that could perform actions like the Raid Marking system, but for players outside the same group (by use of a hidden default chat channel, similar to the way DBM communicates).

Already worked out some of mapping issues with allowing fullscreen map pings/beacons, but I am stuck on how to actually produce a visual mark on the enemy NPC.

Any pointers, references, links, cure for cancer, etc would be greatly helpful.

-Hateborne

This is because you can't. AddOns cannot interact with the 3d world.

If you have nameplates enabled, it would be possible to communicate an enemy's GUID and affix an icon to the nameplate... but it would be quite limited in that (a) you would have to be in nameplate range of the enemy to see it, and (b) the icon would only be shown after you moused over the nameplate, and each time you went out of range, you'd have to mouse over the nameplate again to get the icon to show up.