Is there an easy way to detect megaprims?

I'm investigating a crash issue that I suspect is related to megaprims. I'd love to have a way to sort of sweep the sim looking for megaprims (basically anything with at least one dimension over 10m), but right now all I know to do is fly around with draw distance way up.

I have this thing called a TrashFinder that flies around the sim and reports object names and locations, but it's not very feasible for sims with thousands of prims, and doesn't know anything about object size. Has anyone done a megaprim finder? Also, would such a thing even be possible? Does a scripted megaprim report its correct dimensions?

Also, if you don't own a sensed object, are you even able to get its dimensions, like through a query based on its object key, or can you only do that with objects you own?

Scripted objects, physical objects, particle and sound generators- all a cinch. These megaprims, though, don't seem as easy to track down without truly eyeballing every inch of the sim.

While this is a bit presumptive, I doubt that there would be *any* crash issue related to say, a 40x40 megaprim, unless of course it was turned physical (and any regular prim can cause very comparable issues).

The whopping big ones - yeah maybe. But those are very hard not to notice. If your draw distance is say, 256 and you have highlight transparent turned on, go to the middle of your region and look around. Maybe fly up a bit. But I *really* doubt this is your problem.

What sort of crashing symptoms lead you to believe it is stemming from such a prim?

Also, if it's physical go to the debug controls of the sim, and hit 'show beacon' on the worst offenders... doesn't matter what it is, it will highlight it.

There isn't really a reliable way of detecting them via script.

But some possibilities are:

Use llGetObjectMass() to find really massive objects. But a object made from several 10x10 prims is also massive.

Use llGetCreator() to find objects made by Gene Replacement.

Does that work for a linked set?

You can have a base prim made by you, link megaprims to it, and the set as a whole will show your creator tag only.

llGetObjectMass is a good idea, also llGetBoundingBox
You'd need to use llGetObjectDetails to check the creator of another object

Brilliant idea.

You're right, it wont work for a linked set. But megas tend to be difficult to link and so are often left as single prims.

I dunno Desmond. As there is no authoritative guide on megaprims, it's difficult to kind of distill all the facts about megaprims out of the few Linden quotes and forum posts we have about them.

From what I've read and heard anecdotally, a megaprim doesn't have to be tagged as physical to cause stability issues. I'll give you a specific case: I've been sponsoring a public build of a large (90m2) space station that makes use of several of the smaller megaprims. When this build went live, the sim it was in crashed several times a day. Even though sim statistics showed a fair amount of "physics time" going on, there were no physical objects anywhere on the parcel. After many days of investigation, it was determined that the sim would crash when people rode the little sit-jumper teleporters to move between levels in the space station. These kind of teleporters are used all over Second Life with no real issues that I know of, but in this build they crashed the entire sim. My guess is that megaprims played a part, as avatars passed through them to go between floors.

I really don't understand all this Havok stuff, but even though a megaprim floor isn't "physical" it still has physical properties if it's non-phantom, right? I mean you can walk around on them and stuff. Avatars are physical entities, and I imagine that they can 'collide' with a non-phantom non-physical megaprim, yeah?

In the sim of mine that's currently crashing, I KNOW there are megaprim floors about, but I don't know where all of them are. It's a class 5 with a low prim and script count. A couple months ago the sim was crashing daily, and we discovered it was because one tenant had a pile of 50 physics-enabled gold coins stashed away in a little cave. But there hasn't been a true physics-enabled item in the sim since, that I've been able to detect. And yet we're crashing again.

From my experiences, 'reasonably' sized megaprims 100m and less don't affect a thing, stabilitywise - I've been using them in a coupla dozen Caledon sims for over a year now.

Honestly, there's no difference I can discern except for an old, odd clientside bug having to do with anyone running the Linux alpha version client. That includes when I had some of the whopping big prims out.

As for physics, yes, they do interact collisionwise but if megaprims were that faulty, I'd have 7 or 8 sims blowing up every few minutes - check out my Skycity, Stormhold, Tanglewood, Penzance or Morgaine sims - very intense megaprim use, no problems.

I personally suspect sim crashing due to interaction with a certain avatar or avatars, but of course that's just speculation. One can load down an avatar with some amazingly icky things, not even know it, interact with the world and... boom.

If you tell me your sim name, I can check it out in the next day or so - I can tell all kinds of things just from the basic stat view.

It's called Desperation North, and accessible from Search > Places or the world map.

I'd be happy for the help. =)

I'll have a look when I can, in the next few hours likely. If you *truly* can't find a cause for the crashing and neither can I, Andrew Linden is looking for just a few 'reliably crashy' sims to check out Havok 4 prior to gridwide release, from what I've heard.

Send him an IM - it may get worse before it gets better with a beta version of Havok 4, but at least it will be looked at.

Wildefire,

Why not just use Concierage Support to get a Linden into look into why it's crashing? I mean, you own the island, so pay for the Support. Why not jump on Live Chat and use it?

~Jessy

Of course I am doing that, and have in the past. However, support tickets take several days to process, and I'm not getting my hopes up. In previous cases, concierge has just told me "look for physics collisions around these coordinates." Period. I believe the Lindens were involved in the investigation with the space station, but it was the fella built the thing who made the discovery about the teleporters. I don't see what's wrong with equipping myself to investigate problems on my own land. This is Resident Answers after all.

Hee. I made a megaprim zeppelin using a fairly standard vehicle script and spent a whole evening flying it around. Didn't crash any sims, though I did get logged off on one sim boundary crossing.

I'm not recommending this sort of thing as a general practice, of course--I knew the sim owners, and no one seemed likely to come after me with pitchforks. Still, it struck me that perhaps some of the reported issues with megaprims are hardly consistent, and perhaps slightly apocryphal at times.

I made a "house call" to see if I could find anything, but sorry to report I didn't find much to arouse suspicions. (Well... if security orbs could crash a sim, this would be the sim they'd crash. I've never seen such hair-trigger security before, complete with llTeleportAgentHome() and second-by-second countdowns--each accompanied with a PDS advert thank you very much--faster than they could be clicked from the screen. The second time I got TP'd home after being cornered between two competing neighbors' security orbs and a no-entry parcel, I gave up. )

The *only* physical things I found (other than avatars) were two little temp-rezzed 3-prim particle-sprite "pets" that seem innocent enough. Although, as the *only* apparent scripted physical objects, maybe they're the prime candidates for eliminating, as a test.

I ended up using the teleporters in the space station quite by accident. It's fairly common for these llSitTarget TPs to use a little physics at the destination, to give the avatar a gentle shove--and I've seen this go rather dramatically haywire, but never in a way that seemed likely to crash a sim. I can conjure a "just-so story" for how a just-transported avatar collides with the mega-prim floor at the destination, gets stuck, gets pushed by the TP script, Havoc somehow tries to "push back" with the mass of the megaprim, bad stuff happens... but that explanation is only compelling when the mumbled parts are accompanied by vigorous hand-waving. And yet, if that's still showing as the culprit coordinates, maybe try warpPos teleporters instead, just to see if it makes any difference.

Checking the region precisely now.

Things seem fairly good except for one thing.

time dilation - good
sim FPS - stable at 45 most of the time
physics FPS - 44ish - good

11 agents in the sim and 4 that the sim can 'see' nearby, not too heavy with avatars,

objects 13000ish - fairly full but okay, images time is < 0.1 so it's not texture laggy

active objects 950ish - a tad high but okay,

active scripts 5800 to 6000. DANGER, WILL ROBINSON! *flails arms*

* * * * *

What's going On.

Alright. Mind, the Company changes how sim code works *all the time* so I risk being horribly outdated by even the slightest update.

But if anything has held fairly constant for a while - you've got a lethal raw number of scripts there. Anything over 300-3500 is kinda pushing it, 4000 can be done but don't expect stability. 6000 - I'm amazed this thing is stable at all.

Now, without getting too geeky, it's not the scripts themselves or how 'laggy' they are individually, it's the overhead required, keeping track of 6000 scripts, running or not. Remember all 6000 must be *managed at once* and run in little slices nearly simultaneously - even if shut off, they still need to be managed.

Perhaps removing the teleporters brought you down from 6500 scripts or something - hard to say.

So where are these scripts?


* * * * *

Witch Hunting.


I'll betcha that your 950ish active objects don't have 6 scripts each. More like you've got a coupla thousand scripts there, and 4000ish on the 11 avatars in the region.

Well, okay, my avatar had two of them. So that may be 3998 scripts on 10 avatars.

How to find out for sure? Get yourself a stripped down av (remove EVERYTHING scripted) and get everyone else out of the region. Look at # of active scripts - that's what's in your prims.


* * * * *

Nobody Expects the Sim Owner Inquisition!


So let's say I'm right, and you've got only a coupla thousand in there... WHO is the walking sim crasher?

Alright, you can try to question people all day. But the worst offenders don't realise that their 800 prim change-color-on-command wings are walking script emporiums.

Nor may they realise their supa-sekrit login scanny thingy is sampling so often that almost nothing else in the region can run. Why, they quit paying attention to it two months ago...

So how do you tell?

Once upon a time, avatar script load was detectable with the sim debug tools, but then they went and hid it. Aww, what a shame! But ve haff vays...

You can either tell people what you are doing and hope they cooperate, or Purely Hypothetically you could just invite them to 'sit down and talk to you' - on a chair object named, say, InquisitionChair. Their avatar is now a child object of the linkset - and thus can't help but report itself to the sim debug tools.

NOT that I have ever done this Of Course.

So you take the region debug tool, hit refresh and look for InquisitionChair. Perhaps it reports a script time of 0.010 - this person's clean, let em finish their tea and move along. Odds are, they aren't the one with the killer script load.

Incidentally, many good avatar device makers have cleared their devices this way; you'll note that Mystitool users have a *very* light impact on the region when idling. Well, if that's all they are using - they may be loaded down with other stuff.

So you check a few folks, and you find someone clocking in at 2.530. Alright, that guy is sucking down over 10% of the script resources right there. Bet he has awesome prim hair, too... but hey, here's a GOOD candidate to talk to.

So that's a good way to get an idea what's going on, very roughly, if you have script problems with avatars carrying too much.

And ah... one last wee little mention - that scanning method will work on your own avatar too... shh!

* * * * *

No avatars were harmed, probed, or otherwise violated in the creation of this post. I deny everything. *flees to Caledon*

Quite.

that was quite geeky, desmond. you may even rival qie in overall geekiness.
tell me an easy way to determine if my own av is a resource hog. 600 prim body armour is obvious, but what about hud objects? my ao? is there a simple way to analyse myself (bearing in mind i wave no simgod tools at my disposal).

Not too easily - I'd say the best way is have a friend in a sim with you, and look at overall stats - then leave and swap yourself out with a completely scriptless, no-prim avatar.

The difference in the sim stats, after say a minute once everything has stabilised from the teleports, is roughly what your impact is.

Note however that sims do things in the background and there's a lot of dynamic activity, so getting steady numbers for you vs a low impact avatar may be kind of tricky. Be sure to look at Time (ms) stats, and know what they mean, &c.

The number one 'lag' factor is typically too much in the way of textures, I've found. Keep an eye on images time for a healthy sim. Although this rarely crashes it, if the image cache overloads and stays that way, you are looking at 'walking through molasses' until you restart the region. Verrrry common.

If the suspicion is that it's an avatar, would it not be possible to periodically log who's in the sim, and after a few more crashes, see if any one avatar was present during them all?

Yes, but with a few problems.

If it's a crash-on-entry the avatar detector may go down with it.

If it's a cumulative thing, say with 4-5 people around who are heavily loaded down with wonky scripts, you may have a situation where somebody relatively light and innocent interacts with something... the straining region faults and goes bye-bye.

* * * * *

Again, it's a presumption - remember I couldn't really see exactly who or what had those 6000 scripts. It *could* be items in the region itself, but without estate management capability I can only speculate.

And I most pointedly did *not* offer to peek with estate tools in Desperation North - that's for sim owners to do on their own.

It's a privacy issue more than a security issue to me, and 'too much information' on par with having to find something deeply hidden away in your grandma's bedroom...

I think (wild guess though) collision time is part of the physics time? In that case you should be able to look at the top colliders through the estate window to narrow it down (I never used it btw, I just know it's there ).

It doesn't have to be megaprims either, I ran into a bug that sends the physics time up anywhere between 200-600ms. The cause there was an avatar sitting on a non-physical non-phantom linkset, intersecting with the (sim's interpretation of) bounding box of a non-physical non-phantom sculpty linkset.

Thanks to all who stopped by to have a look! I'm sorry about the orbs! Blanket ban lines (access lists) are forbidden on all my islands, but orbs are allowed so long as they follow my recommended setup guidelines. Unfortunately, as estate owner I never see banlines, and most tenants add me to their orbs, so I never know there's a problem until people report it. I'll have one of my deputies fly around and make sure folks are complying.

Regarding the crashes, I'm hoping LL can point me in the general vicinity of the crashes. I have uptime monitors on all my islands that email me whenever a sim comes back online, and it looks like all the crashes on that island occur between 7pm-8:30pm PST. This might point to a problem with a given avatar if this person is typically logged on at those hours. (Thinking of that poor girl whose MystiTool crashed every sim she visited.) If I can figure out who's normally on at that time I might get closer to an answer.

I've been using some megaprims in our latest builds, and the only problems I'm getting are:

1. Using ALT and mouse movement can throw the camera off. It's like the megaprim was covered in slick ice.

2. It can be hard to find a spot on the megaprim that will allow you to rez an object.

I've been fighting a crashy sim for nearly 6 weeks now. At first it was crashing every hour, but we found the fancy builds used a lot of toruses, which didn't take kindly to Avatars passing through them. Set them all to phantom. That got us to where we are now, crash once or twice a day. I have called the Lindens out, and after making their inspections, they pointed to two things. Apparently Huge prims that stick out beyond the sim boundary are considered a bad thing. And in fact it doesn't have to be the prim itself, but even just it's bounding box. you can see the bounding box by trying to resize it, or observing it on the mini-map.

The second thing was Warppos Teleporters. They have all been eliminated, and the crashing continues. So the Lindens were about as helpful as another hole in my head. I'm prepping to have the tenant the problems seem to center around to move to another sim, to both verify the problem lies there, and to stop annoying the other tenants in the sim with all the crashing. It's a painful thing to do but I'm at my wit's end (it's a huge elaborate build).