The plans that planning systems generate for solvable planning tasks are routinely verified by independent validation tools. For unsolvable planning tasks, no such validation capabilities currently exist. We describe a family of certificates of unsolvability for classical planning tasks that can be efficiently verified and are sufficiently general for a wide range of planning approaches includi...

Path planning technologies have rapidly improved over the last 10 years, but further integration is needed if pathfinding engines are to drive the behavior of even more realistic characters. This paper briefly outlines existing approaches for path planning and suggests scenarios where integration of information about character’s relationships could improve the quality of path planning in games.

This paper is devoted to path planning when the safety of the system considered has to be guaranteed in the presence of bounded uncertainty affecting its model. A new path planner addresses this problem by combining Rapidly-exploring Random Trees (RRT) and a set representation of uncertain states. An idealized algorithm is presented first, before a description of one of its possible implementat...

This paper addresses the problem of optimizing the navigation of an intelligent mobile in a real world enviroanment described by a map The map is composed of features representing natural landmarks in the environment. The vehicle is equipped with a sensor which allows it to obtain range and bearing measurements from observed landmarks durinq the execution. These measurements are correlated with...

The paper describes an application of the A* algorithm for flight path planning for airplanes with defined motion dynamics operating in a continuous three-dimensional space constrained by existing physical obstacles. The presented A* algorithm modification provides significant acceleration (reduction of the state space) of the path planning process. The described algorithm is able to find a pat...

In games entities move around and must find their routes to various locations. These routes must be collision free, natural, and computed very fast. This is a major challenge and many games solve this by using precomputed waypoints, scripting, or simple but fast methods based on grid search or potential fields. Also very often they cheat or accept the fact that characters walk through objects. ...

We propose the use of quasi-random sampling techniques for path planning in high-dimensional conng-uration spaces. Following similar trends from related numerical computation elds, we show several advantages ooered by these techniques in comparison to random sampling. Our ideas are evaluated in the context of the probabilistic roadmap (PRM) framework. Two quasi-random variants of PRM-based plan...

Grids with blocked and unblocked cells are often used to represent terrain in computer games and robotics. However, paths formed by grid edges can be sub-optimal and unrealistic looking, since the possible headings are artificially constrained. We present Theta*, a variant of A*, that propagates information along grid edges without constraining the paths to grid edges. Theta* is simple, fast an...

In robotics and video games, one often discretizes continuous terrain into a grid with blocked and unblocked grid cells and then uses path-planning algorithms to find a shortest path on the resulting grid graph. This path, however, is typically not a shortest path in the continuous terrain. In this overview article, we discuss a path-planning methodology for quickly finding paths in continuous ...