Beta Server Office Hours/Minutes/2012-07-12

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Revision as of 14:47, 19 July 2012 by Oskar Linden (Talk | contribs)

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This meeting was held on July , 2012



  • Big week.

  • Magnum RC Channel
  • This is the Pathfinding Project.
  • Features and Changes
    • Havok's AI library has been added so that navigation meta data for an entire region can be computed. This data is called the "navmesh".
    • SL objects can be turned into "characters" which use the navmesh to navigate the world and avoid obstacles.
      • New LSL calls have been added to create/update/delete character behavior.
      • Characters cannot be used as attachments.
      • Characters are incompatible with some features, such as keyframed motion, being used as attachments, phantom, size changes, and others.
    • Not all objects in the world contribute to the navmesh calculations.
      • The terrain always contributes
      • By default objects are ignored for the navmesh calculations.
      • Objects may be flagged to modify the navmesh calculations in one of 4 ways:
        • "Walkable" objects add navigable zones to the navmesh.
        • "Static Obstacle" objects cannot be navigated, and create a hole in the nav mesh
        • "Exclusion Volume" objects are like static obstacles, except that they are phantom (meaning that pathfinding characters cannot move through them but other physical objects and avatars can)
        • "Material Volume" objects are phantom objects that can be set to change the walkability coefficients of an area of the navmesh
        • Material volumes and walkable objects have 4 walkability coefficients to determine how expensive they are for each category of character
      • Objects that contribute to the navmesh have special restrictions:
        • Objects that contribute to the navmesh cannot change their physical shape via LSL script (changing object position, shape parameters, scale, rotation, physics shape type, and linking/unlinking is generally blocked)
        • Objects that contribute to the navmesh can be physically changed via the build tool by avatars who have modify permission and if the avatar is in the same region as the object.
        • In other words: objects that contribute to the navmesh cannot be physically changed by avatars who are located in a different region than the object, and therefore such objects cannot be moved across region boundaries.
      • When the navmesh has been modified, either because the terrain has been edited or because an object contributing to the nav mesh was rezzed/modified/deleted, it must be manually regenerated.
      • The pathfinding project viewer can be used to modify the pathfinding settings in a region:
      • Parcels that are set No-Entry for objects will cut the navmesh at their borders -- characters will not be able to navigate across it.
    • The collision pipeline has been reorganized. This may affect avatar collisions/control, vehicle movement, and collision callbacks in LSL scripts.
    • The terrain collision shape has been changed from a "heightfield" to a "mesh" to provide more efficient collisions, ray-trace, and navmesh computations.
      • This may change some collision details. In particular see the "Known Issues" list below.
      • When changing the terrain its visible appearance will update immediately, but its collision shape will not.
      • The server will wait at least 10 seconds since the last change before computing the new shape, and the computation time may take several seconds.
      • Where there is a discrepancy between visible and colliding terrain shapes object and avatar collisions may appear incorrect.
    • Fix for PATHBUG-77 "llCastRay returns RCERR_CAST_TIME_EXCEEDED until the sim is rebooted"
    • Avatars which are sitting on an object can no longer freeze it by selecting it, if they don't have permission to freeze it while standing.
    • More details about pathfinding can be found at and its linked pages
  • Changed prim accounting for legacy prims which use the new accounting system
    • All legacy-style prims have their streaming cost capped at 1.0 (except for sculpts, which will be capped at 2.0). This provides the benefit of not penalizing prim-based creators for optimizing their content by opting into the new system and will make the streaming cost more reflective of the true network cost of the objects.
    • Server cost will be adjusted to MIN{ (0.5*num_prims) + (0.25 * num_scripts), num_prims }. This preserves the current value for unscripted linksets and reduce the cost for linksets containing fewer than 2*num_prims scripts. It provides the benefit of rewarding creators for reducing the number of scripts in their objects.
  • Fixed the following bugs since the Pathfinding RC
  • PathFinding User Group right after this meeting.


Transcript of Oskar Linden's Server Beta User Group for July 12, 2012: