When Pathfinding was in development I had some concerns about how it would affect Second Life™ performance and especially about how hard it would be for region and land owners to implement. I wasn’t the only one. Rumors got started and region owners freaked out. The result is many turned off Pathfinding for their regions.
Surprisingly today, many region owners apparently still turn off Pathfinding thinking it is going to improve region performance. After all, if it isn’t running it can’t use up CPU cycles. Right? Wrong.
Whether Pathfinding is on or off the core functionality uses the same amount of cycles. Enabling or disabling Pathfinding is like enabling or disabling building in a region. The only affect is has on performance comes from whether people add prims or not. It isn’t the enable-disable that affects performance, it is the number of prims added. Otherwise, nothing in the server’s operation changes. This is just another setting that controls what people can do, not what the simulator does.
Disabling Pathfinding does not change what the region does. It does change what users can do. They either can (enabled) or cannot (disabled) run a Pathfinding character.
In a recent thread on the SLUniverse forum Darien Caldwell posted the stats from a region with Pathfindng enabled with no characters and with 1 and then 6 Pathfinding characters. Running no Pathfinding character uses up no sim cycles (0.002ms of spare time) enabled or disabled. Adding 1 character uses up 1.5ms of the sim’s spare time. Each additional character uses up about 0.1ms of additional time.
See Darien’s stats posted here: Questions about SL Pathfinding: Current status.
Pathfinding is designed to run in the simulators spare time. So, if you have a laggy region, you are going to have horrible Pathfinding performance because the region has no spare time to give to it. But, disabling Pathfinding is NOT going to fix or even help your laggy region.
It is always nice when someone takes the time to check things out. Thanks Darien. But, it is really hard on rumors and people’s misconceptions when they do.
There is the question of why turn on Pathfinding? The idea behind it was to hopefully make creatures like breedables more efficient. The server’s Havok physics could use highly optimized code to handle movement. This saves the designer from having to use bulky LSL to code in Artificial Intelligence to handle movement.
So, the choice is to have PF on and allow more efficient breedables and other characters or load the region with huge LSL scripts to accomplish the same things.
I’m not sure what most makers of breedables are designing. I would design for either possibility; PF enabled or disabled. I might put in additional features for PF enabled regions.
PF to all appearances has not taken off. We see few places where it is used. I’m not surprised. It is only about a third of the Non-Player-Characters (NPC) system I think is needed. We are missing a better permissions system, which we hope to get with Advanced Experience Tools. We are also missing a better NPC animation system. Without those PF is somewhat restricted.