Stay off the lawn - Creating smooth paths based on region - PowerPoint PPT Presentation

Stay off the lawn - Creating smooth paths based on region preferences Norman Jaklin 1 Atlas Cook IV 2 Roland Geraerts 1 1 Utrecht University - Department of Information and Computing Sciences 2 University of Texas at Austin - Institute for Computational Engineering and Sciences ASCI.OPEN / ICT.OPEN 2013 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 1 / 19

Overview of our research Path planning and crowd simulation for virtual autonomous agents General framework based on Explicit Corridor Map [1] Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 2 / 19

Overview of our research Research on the data structure itself Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 3 / 19

Overview of our research Research on virtual crowds Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 4 / 19

Overview of our research Combining individual steering behavior with coordinated crowd movement Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 5 / 19

Motivation Problems with terrain-based path planning in current games and simulations World of Warcraft by Blizzard Entertainment 2004 Grand Theft Auto IV by Rockstar North 2008 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 6 / 19

Problems with terrain-based path planning in current games and simulations Inflexible solutions for handling individual terrain preferences Traversable areas treated as equal, independent of individual terrain preferences Unattractive traversable terrain is made impassable for particular characters Grand Theft Auto IV by Rockstar North 2008 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 7 / 19

More problems Paths are often illogical and not visually convincing Unnecessary detours No smooth trajectories Unnatural clearance from obstacles Characters do not look ahead enough Obstacles or rough terrain is ignored World of Warcraft by Blizzard Entertainment 2004 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 8 / 19

MIRAN - Modified Indicative Routes and Navigation Input: A 2 D polygonal environment Virtual characters with sets of individual region preferences An indicative route that roughly guides a character automatically computed or manually designed Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 9 / 19

MIRAN - Modified Indicative Routes and Navigation Output: A natural-looking path that gives the user control over the amount of smoothing is based on a character’s region preferences keeps clearance from obstacles avoids unnecessary detours can be computed in real-time Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 10 / 19

The MIRAN method - Overview Step 1 : Compute reference point on the indicative route Step 2 : Compute set of candidate attraction points Step 3 : Pick best attraction point Step 4 : Move character towards attraction point Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 11 / 19

Two user-controlled parameters The shortcut parameter σ The sampling distance d indicative route d character position σ Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 12 / 19

Step 1 : Compute reference point r r i := first closest point on the indicative route between former reference point r i − 1 and former attraction point α i − 1 indicative route α i − 1 r i r i − 1 x i Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 13 / 19

Step 2 : Compute set A of candidate attraction points Visible points along the indicative route between r i and σ i discretized with sampling distance d goal α i 7 σ i α i 6 α i 5 α i 4 α i 3 x i α i 2 start α i 1 r i Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 14 / 19

Step 3 : Pick best attraction point α from A Each line segment between x and α j is weighted with the underlying type of terrain and the curve length distance from r to α j . Lower terrain costs ⇒ lower weight α j further ahead on the indicative route ⇒ lower weight goal x α 3 start α 2 r α 1 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 15 / 19

Step 4 : Move character towards α α 1 α 2 α 3 x 4 x 3 x 2 x 1 Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 16 / 19

Forest example Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 17 / 19

Future work Improve the computation of indicative routes Handle disc-shaped characters with variable radius Extend terrain-based planning to local collision-avoidance routines Use continuous set of candidate points instead of sampling the indicative route Generalize MIRAN to (multi-layered) 3 D environments with height information Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 18 / 19

Thank you! R. Geraerts. Planning short paths with clearance using Explicit Corridors. In Proceedings of the IEEE International Conference on Robotics and Automation , pages 1997–2004, 2010. N. Jaklin, A. Cook IV, and R. Geraerts. Real-time path planning in heterogeneous environments. Computer Animation and Virtual Worlds (CAVW) , 24:285–295, 2013. Jaklin et al. (Utrecht University) ASCI.OPEN / ICT.OPEN 2013 19 / 19