Line of Sight (LoS)

Definition - An unobstructed (clear) view between two toons and/or mobs. Taken from radio technology, it refers to the characteristic of high-frequency radio waves to travel only in straight lines - much like light - resulting in the requirement for there to be a clear path for transmission between transmitter and receiver.

Usage - "You died, Shystechris, because ONCE AGAIN you got out of LoS of the healer..."

Further Detail - In WoW, this applies to spell-casting. Spells can not be cast on targets with which they do not have line of sight. This goes for damage spells and healing spells, alike. Tanks can use this principle to their advantage when dealing with spell-casting mobs. The tank pulls the mob by intentionally producing aggro (see article "Aggro vs. Pull: Yes, There's a Difference"), and then moves to a position that is out of LoS from them, causing them to run to the tank in order to attack her. A lack of awareness of LoS between a party and it's healers, however, can have devastating results. Heals are spells and are therefore held to the same LoS rules. Remember, very few heal spells can be cast while the healer is moving, so tanks and DPSers need to have an awareness of where they are in relation to their healers, or they risk stacking too much of the Death de-buff (a.k.a., damage) before LoS can be re-established. Please note the following common obstructions to LoS:

• Walls (and most half-walls)
  
• Some trees
  
• Hills
  
• Walls
  
• Stairs
  
• Pillars
  
• Wardrobes (but not lions nor witches)
  
• Walls
  
• Some shrubbery
  
• Large, natural formations (see Trees, Hills)
  
• Large, man-made formations (see Walls)