1. Indicative Routes for Path Planning and Crowd Simulation
Ioannis Karamouzas, Roland Geraerts, Mark Overmars
2009
Walter Kerrebijn

2. Introduction Path Planning in Interactive Environments:
(large amount of) entities from Si to Gi
avoid collisions
real-time
natural

3. Related Work Methods in Game Development: Grid-based Navigation Meshes
Waypoint Graph
Combined with reactive steering approach

4. Indicative Route Method (IRM)
Based on Corridor Map Method (CMM)
Corridor Map
Backbone Path
Attraction Point
Indicative Route
Different potential function

5. Indicative Route Method (IRM)
Comparison between CMM and IRM

6. Indicative Route Method (IRM)
2D or 3D environment
Character from S to G
modeled as disc/cylinder with radius r
Avoid collisions with static/dynamic objects
Three phases of path planning

7. Three Phases
Indicative Route
Corridor
Path Extraction

8. I. Indicative Route Can be created with Waypoints
Path extraction from medial axis
A* search in grid

9. II. Corridor Corridor Map Graph G = (V,E)
Generalized Voronoi Diagram (GVD)
Backbone Paths
Skeleton ‘densely sampled’
radius of largest empty disc

10. II. Corridor

11. II. Corridor Retraction:
Translate each point on indicative route to the medial axis
for discrete number of points

12. III. Path Extraction
Using force field approach

13. III. Path Extraction
Weighted combination of forces on character used for ‘steering’ locally
Repulsive Forces
Steering Force
Noise Force

17. Phases

18. Scenario

19. Results