Combinational Vector Field Pathfindinganima/408/Notes/Crowds/VectorField.pdfUNIVERSITY OF REGINA ....
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JOHANNES MOERSCH & HOWARD HAMILTON UNIVERSITY OF REGINA Hybrid Vector Field Pathfinding
Transcript of Combinational Vector Field Pathfindinganima/408/Notes/Crowds/VectorField.pdfUNIVERSITY OF REGINA ....
J O H A N N E S M O E R S C H & H O W A R D H A M I L T O N
U N I V E R S I T Y O F R E G I N A
Hybrid Vector Field Pathfinding
The Problem
The Method
A* for Long-Range Pathfinding
Crowd Continuum for Medium-Range Pathfinding
Waypoint Graph
A way of planning routes for characters that is not used much any more
NavMesh
Short for Navigational Mesh
Constructing NavMesh
A navmesh can be constructed by starting with one polygon (typically a rectangle) representing the overall area. This is the initial open area.
Add the obstacles, each modeled by a polygon, one by one.
When an obstacle is added it is either completely inside the open area or overlaps part of it (otherwise it wouldn’t be an obstacle!).
Split the open area into more polygons by drawing a line segment “out” from the obstacle all the way across the open area (example follows)
Constructing NavMesh
Suppose a white obstacle is placed overlapping the blue open area. Draw lines outward to form new polygons. Remove area covered by obstacle.
Constructing NavMesh
Four cases for consecutive vertices of the obstacle polygon were identified, as shown below.
Traversing NavMesh
To measure the lengths of a path through a navmesh, go from the center of one connecting side to the center of the other connecting side.
Density Map
Velocity Map
Legend for Directions
+x −x
−y
+y
Speed Map
Cost Map
Potential Field
Fast Marching Method
Vector Field
Legend for Directions
+x −x
−y
+y
Lane Formation Results
Congestion Avoidance Results
Maze Results
Performance Results
64x64 128x128 192x192 256x256
4 ms 18 ms 37 ms 65 ms
References
Cui, Xiao. “A*-based Pathfinding in Modern Computer Games” IJCSNS January 2011. <http://paper.ijcsns.org/07_book/201101/20110119.pdf> Gas Powered Games. “Supreme Commander 2 ‘Flowfield Pathfinding’ Trailer” Youtube 2010.
<http://www.youtube.com/watch?v=bovlsENv1g4> Shopf, Jeremy. “Crowd Simulation in Froblins” SIGGRAPH 2008.
<http://s08.idav.ucdavis.edu/shopf-crowd-simulation-in-froblins.pdf> Tozour, Paul. “Fixing Pathfinding Once and For All” ai-blog.net 2008. <http://www.ai-blog.net/archives/2008_07.html> Treuille, Adrien. “Continuum Crowds” SIGGRAPH 2006.
<http://grail.cs.washington.edu/projects/crowd-flows/continuum-crowds.pdf>
