Unity Tutorials - Intermediate 01 - Raycasting - Unity3DStudent.com
How to detect line of sight by using ray casting.
Part of the http://www.Unity3Dstudent.com teaching program by Will Goldstone, author of Unity Game Development Essentials.
Learn Unity game engine in short modules that give you the skills you need abstracted from game scenarios to maximise your creativity and complete challenges based on these modules to test your skills.