Can anyone tell me what raycasting is and what it is used for
How can you implement it ingame?
I have read up on the wiki and found nothing that explains it.
Raycasting is used mainly for guns and other weapons. It draws a ray starting at point A and going in the direction of point B until it hits something, or forever. Here's an example of Raycasting in use:
http://wiki.roblox.com/index.php?title=How_to_Make_a_Raycasting_Lasergun