Pathfinding and region performance – Lorca Linden comments

Nalates Urriah has been keeping an eye on the more technical aspects of pathfinding, and has routinely provided excellent updates and commentary on the project. Her work is largely the reason I’ve not delved overly deeply into the subject here, and why my own Pathfinding overview attempts to cover the subject from a lay user’s perspective.

Alongside yesterday’s roll-out came a lot of confusion regarding pathfinding and its impact on region performance. As a result of this, Nalates published a piece seeking to clarify matters. If you are concerned as to the impact of pathfinding, and you’ve not already done so, I thoroughly recommend you give her article a careful read.

Today, Lorca Linden took the extraordinary step of commenting on Nalates blog in order to lend further clarification on the subject. While I do not agree with his stated reasons as to why Linden Lab did not communicate more on the actually roll-out (which, in fairness, has potentially contributed to the confusion / misinformation circulating about pathfinding), the key points of Lorca’s comments vis-a-vis overall performance are nevertheless important in helping to spread better understanding of the matter. I’m therefore reprinting his comments here in full, with the key paragraph on performance underscored, in the hope that it will help them reach a wider audience.

“Although Lindens do not generally post on Resident blogs, I am going to make an “exception in this one case. Don’t expect us to make a habit of it, though 🙂

“I want to start off by thanking Nalates for what I feel has been even-handed coverage of pathfinding as a whole. While I disagreed with several of the assertions made in the “Tsunami” post, it did make us realize that there were misconceptions about pathfinding that needed clarification (particularly in regards to performance implications) and was a useful data point in identifying Resident concerns while we were still in the development phase.

The 18% performance hit figure referenced on the Phoenix Viewer blog is a worst case scenario that will rarely be seen in practice – eg, you could see that large of a hit on a poorly optimized region that contains hundreds of pathfinding characters running simultaneously. Average perceived (viewer side) fps grid wide was actually .03 fps higher yesterday afternoon than it was the afternoon before. Average server-side performance grid wide was also inline before and after pathfinding server code was rolled out. Region crash rates – excluding a bumpy couple hours during the roll out – remain low. All of this is to say that as far as the Lab can tell, Pathfinding has not had a negative performance or stability impact in the vast majority of situations.

“I also want to make clear that the impact on some vehicles is not directly related to pathfinding per say but rather the underlying physics and terrain optimizations that made pathfinding possible and have benefits beyond pathfinding. As far as we can tell, only a small percentage of existing content is affected by this physics upgrade.

“We do not consider pathfinding to be fully released until the pathfinding viewer tools are out of beta. This is why we have not yet made an official announcement. I agree that we need to do a pass on our pathfinding related wiki as some of the information there has not been updated since we were in alpha. We plan to make a blog post in the near future that will address some common misconceptions we have heard about pathfinding. We also plan to continue updating the “Good Building Practices” guide so that it will be a useful resource for Residents looking to make optimized content.

“We understand that pathfinding can be a confusing topic at times and appreciate the effort interested Residents are making to absorb the technical details. If you have any burning questions about pathfinding, please come to our user group on Pathtest1 (on Aditi) at 4PM SLT Thursdays and ask away. Above all, we are extremely excited to see what you Residents create with the new pathfinding tools and LSL functions!”

15 thoughts on “Pathfinding and region performance – Lorca Linden comments

      1. Horrible… noticiable. Viewer performance pegged from the moment I logged on. I “set dynamic_pathfinding off” but waiting for a sim restart to see the results. With Pheonix viewer, each time I log on I find parts of previious outfits still attached, and so forth. it’s not good.


        1. Have you tried a different viewer to see if you have the same issues? Equally have you tried logging-in elsewhere using Phoenix to see if the same issues occur?

          Outfit issues sound to be more of a bake issue more than region performance – and that could well be your end of the equation, due to a variety of reasons. It’s always a last-ditch thing to do, but have you cleared your cache at all?


          1. Hi Inara… I spent a solid hour rebuilding my avatar and inventory from scratch on an empty sim. That finally did the trick. It also cleaned up some old issues I’d been suffering with. I know of one other Phoenix user who was impacted. We are all good now.


        2. I noticed things were pretty bad, generally, on Thursday, but I suspect there’s something going on down in London which is putting a lot of load on the Internet in the UK…

          All credit to Lorca Linden, but the Lab needs to get their act together on communicating with the customers. Without the Resident blogs putting together what trickles out from multiple, uncoordinated, sources, we’d know nothing.


          1. After some scrambling around, I’ve restored my av & performance. It was a pretty big shock though when things seemed to be falling apart. Skeery but we are past it for now.


          2. No arguments from me on the communications front; I’ve been banging that drum for so long and so regularly now, I’ve been offered a place in the percussion section of the Royal Philharmonic! Lorca did well to reach out through Nalates’ blog, and that’s genuinely appreciated.

            However, regardless as to the readiness of the tools, not communicating more generally on pathfinding was perhaps the biggest SNAFU of the roll-out. Let’s face it; it’s not as if LL didn’t know there was a potential for people to get wound-up the wrong way due to misconceptions – they had, after all, Nalates’ own musing on the subject to show them how even somewhat who is knowledgeable on the subject can get confused.

            The idea that there’s no blog post because the tools aren’t in the official viewer is – frankly – nonsense. LL have pointed people towards beta viewers in the past, so there is no reason why they couldn’t again given that, for some reason, they were not prepared to wait another week or so for the tools to hit the release viewer. I’m not blaming Lorca for this; the decision to roll most likely came from higher up – but it does again demonstrate the company needs a serious re-think in terms of when and how it communicates.

            Not that it will happen, of course.


  1. Do you want to know the true reason behind Lorca Post?
    LL did not informed any of the Big Land barons about path finding, its implications and the rest!
    Big Land barons started to get floaded with im’s requesting them to disable path finding, that they did not knew what it means (Perhaps Desmon was aware, i doubt any other!)
    So they start asking why the ones paying the big checks are not informed!
    LL can screw all it wish with us, but Land Barons still have the power!
    Still i can attest that i didn’t had any problems, be on a region with it disabled, be on most of mainland regions that is enabled!
    And no decrease on my region that has path find enabled!
    Still its a bit hard to ask non builders to optimize a region and for sure land barons will not do it!
    To make the rout prim of a link set a simple square or cilinder seems simple buit how many know what is that?
    Now if only one thing its obvious is:
    Users need to move to latest Tpv that are being actualized on a week basis!
    This blog posts accurate info about who are those viewers!
    Funny is that Imprudence non mesh viewer has a boost in performance (I did a race yesterday, one of the drivers was using it, and getting 140 fps when he normally gets 60! )
    So it looks like if any can’t use the tpv that uses the new code, it must go for a non mesh viewer, lol!


    1. I find that worryingly plausible. It’s a symptom of the general Linden Labs talk-fail, but pissing off customers who pay big money is a bad move.

      As for Viewers and Pathfinding controls, the weekly updates are one reason why I keep Cool VL Viewer on my computer. And, on past performance, I feel I can trust Henri more than I can trust Linden Labs. Windows often asks me if I can trust the source of a program: when that message comes up for Cool VL Viewer, I look for the “Hell, Yes!” button.


  2. Just a word about problems with pathfinding. I did notice some strange behavior which was cleared up by Friday the 10th. I did notice faster fps, smoother moving, better graphics. Weather this was pathfinding being enabled grid wide, I don’t know. I do know its on all my sims, now. I use 3.3.6 viewers, Nirans and Catznip. And can we get serious about Viewer 1? It’s dead? It’s just not been buried. If you still use any V1, that’s a big cause of your problem, no matter how much they patch a V1 with v3.3x code..Frankenstein’s Viewer?. oh, and Firestorm is calling its 3.3.x “Version 4”


    1. Interesting feedback on performance there, thank you.

      As to “Viewer 1”, the official SL Viewer 1 (1.23.5) is pretty much dead and buried. However, it’s important to remember that considerable time and effort is going into not so much patching V1-based viewers with V3 code, but fully backporting the code into them, allowing them to maintain a high degree of functional compatibility with V3 for those that prefer the older viewer UI. These V1-based viewer frequently perform as well as their V3 equivalents. Granted, it looks like maintaining parity is possibly going to be more of an uphill climb for at least some of the V1-based viewers (and so some devs are of the opinion it is time to move on once and for all). While I’ve long passed the days of using a viewer with the older UI (which I frankly find cumbersome, antiquated and downright unfriendly), I’d still say the end of line for such TPVs hasn’t yet been reached.


      1. I am getting too used to Firestorm to be really comfortable with Cool VL Viewer, but it is well worth having around. The regular updates for one thing, and the different pattern of potential bugs: if something is behaving oddly, it’s a very useful check.
        I suspect that a good many TPVs wouldn’t exist if Linden Labs did a professional job of UI design: things such as colour schemes and camera positions come to mind.


  3. Well LL should really listen to this:
    While I would love to see the pathfinding feature working great… I can only call it as I see it.

    Pathfinding had to be shut off on many of my estate’s regions because of the clear, obvious, significant, noticeable performance hit when it was on.

    Simple A/B testing. Lindens, if you are reading this ~ go ahead and turn it on in some of my standard Caledon regions for a minute to see for yourselves. This was not any of the other myriad issues going on lately ~ we could see immediate effects just by changing that one setting.

    I’m not against anyone, it sounds like a great feature, but sorry, there is a very real performance hit. Let’s hope things get better with it soon.

    I would assist and try to help with solving it, but time has been precious lately ~ I’m busy earning money elsewhere, that I used to earn in SL.

    Posted by: Desmond Shang | Tuesday, August 14, 2012 at 01:03 PM

    Cause if the Big Barons are getting so pissed they post this, better be careful not to loose more then 1000 regions only on this last month alone!
    And all i can add is that i’m not having no issues while crossing sims, (be on niran v1.47 or latest v 1.49 that is using the latest dev code as since yeaterday!) but mt landlord also turned path finding off on all of her 200 sims and ill have to ask again to United sailing is they did same as New England already and so on!
    And i bet Ash Chung regions are not path enabled as well!


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