Unity3D has a Navigation Mesh System which is an evolution to previous Waypoint system where waypoints need to be assigned and routes via waypoints be built, therefore the navigation of a Non-Player Character (NPC) is limited. NavMesh doesn't have these limits. This short demo shows a boy (Remy), two girls (Maria_J_J_Ong and Megan) running in a warehouse. They run upstairs and downstairs without bumping into each other, chasing the cursor where you click -- you are commanding them! Very fun! Learned from Dr. Penny de Byl in Udemy https://www.udemy.com/course/artificial-intelligence-in-unity/. The Remy, Maria_J_J_Ong and Megan fbx assets are from mixamo.com. The music is by cheesspuff, from https://freesound.org/people/cheesepuff/sounds/109239/