Full sim: what percentage of prims to leave unused?

I have heard (possibly here) that it is best to leave up to one third of the 15,000 prim allotment unused (for a full sim), for better performance. However, today I heard otherwise... supposedly, you can use up the full allotment.

There have been a lot of changes (not to mention technical glitches) lately. So what's the latest conventional wisdom or practical experience?

It would be useful to have this info for both mainland and for class 4 and class 5 islands.

i think a sim can handle quite well the prims alone, keep the prims density constant however will help not to create heavy physical zones.

Usually more prims == more scripts if you happend to use furnitures and prefabs you might neexd to watch it closely.

Also rental sims is the worst of all evil as a lot of tenants will have the tendency to put out for themselve the same scripted object set.

Kyrah's right on this; perhaps I can offer a little bit more detail.



Prims themselves: not very evil.

In fact, the 15,000 prim limit to a sim is:

1) anywhere from probably unnecessary if you have 15,000 untextured cubes out, to

2) ridiculously too many allowed, if you have 15,000 uniquely textured, scripted torii.

In fact, the most conservative limit could arguably be ONE prim. Yeah, one. There's a way to cut and twist a single prim, and turn it physical in such a way that it will bring a sim to a near standstill.

So let's look at the real issues. Lots of prims = clientside object lag. Most people can't handle 15,000 torii on their graphics card; simply too many polygons. But it's rare that anyone would make a sim with 15,000 polygons all in one viewable place.

So it doesn't matter if a sim is class 4 or class 5 or class 8.5 or whatever. It strongly matters what the clientside graphics card capability is - how many thousands of polygons you can render quickly for a good framerate.

* * * * *

Textures:

What surprises me is that there is (presently) no cap on the number of unique textures in a sim. This is the real 'lag monster' as each texture has to be served to each avatar's client.

40 avatars in a sim = 40 x all the sim's textures viewable are served to client computers. This is a little bit more complicated than I'm presenting here, especially with regard to the avatar's textures themselves, but let's stay with the basics.

So let's pretend you have 15,000 cubes in a sim, each face *uniquely* textured with an individual texture. That's 90,000 textures. Not only is your graphics card not gonna handle that, neither is the sim able to serve that without a massive hit serverside.

If I'm correct, this shows up as 'images time' in the statistics window: you'll see the value skyrocket and serverside frame rates drop to a crawl long before you ever get near 90,000 textures. Making sure they are all 512 x 512, or even 256 x 256 isn't going to save you one bit. 90,000 texture downloads times say, 10 avatars viewing - that's nearly a million requests for textures alone.

* * * * *

Scripts:

Scripts were changed a long time back such that they don't have much priority over other server functions any more.

In other words: pile on the scripts, and (generally) only scripts themselves slow down. This won't prevent the average avatar from walking around. It *will* do things like slow down scripted moving objects, interfere with scripted messaging rates (vendors not working, things like that) but it's a different sort of 'lag'.

In fact, many sims I've seen are 'maxed out' with scripts already, and nobody really realises it. Because it doesn't generally matter if scripts are running 10% or 20% more slowly. Whatevah.

I've seen a few ways that script lag is generally caused: either by a few really nasty scripted objects (I won't mention a popular brand of ah, 'avatar interaction' items) or via a vast hoard of small but multitudinous scripts. If your neighbour decides to set out a vendor network server for each 'category' of his items, watch out.

* * * * *

Physics:

Best way to kill sim performance that I know of.

I think we've all been in a sim where someone new decides to make items physical, then de-link the prims for some explosive, physicsy phun. Brace yourself for 2% of normal sim performance the moment a couple of physics-enabled prims interact in an ungood way.

Usually in a few days they get tired of it, and sim framerates go back to normal. Well, once all the spinning fragments are found and cleaned up.

Not all physics is 'bad' - but almost anything complex is sure to cause sim serverside framerate issues.

* * * * *

So, back to the point:

On *average* 10,000 or 5,000 prims are less clientside and serverside lag than 15,000, but it completely depends on what the prims are, how they are scripted and textured, &c. No hard numbers.

Server class doesn't really matter all that much with regard to *prims* themselves. With regard to textures and scripts, that's another story. Class 5's handle script load a lot better than Class 4 sims, for instance.

The best way to kill lag: make all the sim users understand all the issues above. A tough thing to do, when most new folk don't even know what a prim is! But they figure it out pretty fast.

Thank you for an excellent explanation! I have a question though:




Please DO mention the brand of items. If my Xcited Naughty Bits are really bogging things down, whether they're in action or not, I wanna know!

Also, considering that many AVs wear an enormous amount of textured prims, which while they may not count against a Sims allowance, they're still there and have to be displayed in all their complicated/textured glory. Is there any good way to discover how many prims one's wearing at a time? Or is the only choice to examine each item, one at a time?

Anything that is not on a channel causes immense lag. Anything scripted will cause lag, but the ones on a channel don't constantly listen unless you type the channel in.

Lots of the 'bling off/bling on' jewelry out there is constantly 'listening' from the owner which is why many clubs ask you to remove it altogether. Some ask you to turn it off, and that's not always enough, since the particles aren't really the culprit overall, but the script in active listening.

Everything I wear, I have on a channel which helps me out in terms of lag, but coincidentally, unless I take everything off, including prim skirts, I'm causing lag of some sort.

The worst offender, is the hair made of 100's of torus prims, the torus' is bad. Very very bad.

If you need to use scripts, try and make sure they operate on 'channels' as opposed to listening to the owner constantly for a command.

Hi Seola,
Are the scripts you are reffering to as "not on a channel" the scripts which use "normal" chat (channel 1?) for communication with the owner?
So if I have a freebie script which I give commands to, using chat, could I then just change it to say channel 15 and write "/15 help" instead of just "help"? Please explain a newbie..




Is there an easy way to check this before buying the hair (except from asking the creator)?

Bear in mind also that the 15,000 prim limit is the result of LL reserving a HUGE portion of available prims on a sim for wearable objects. So if, for example, you were planning on running a sim where you'll hold Victorian Themed Weddings where the brides and bridesmaids will be wearing something on the order of 500 prims each, you might want to reserve more prims from your allotment than you would if you were running a sim that catered to new residents who aren't likely to wear more than one or two prims at a time. Generally, reserving prims for this reason out of your allotment won't make a huge difference in sim performance, but having run events where the average prim count per avatar skyrocketed past 1000 (curly prim hair and long ball gowns will do that to you), it can make a noticable difference.

Kam

Sorry, I can't.

It's a matter of resident privacy as much as anything else, and I've already said as much as is reasonable.

I'll only say it's not the brand you mentioned.

As for the scripts, I know they have to be moddable, but I'm not a scripter to tell you where or how to insert a channel command.

I'm referring to scripts that responds to "ao on, bling off" as opposed to having to type '/ao on, /5 ring blingoff (this latter / command is WIDELY variable)".

As for the hair, AFAIK, you can check a demo and try to 'see' with your eyes up close, and it might be possible to right click the demo, select edit linked parts, go to the more tab, click on a piece of hair, then choose the second tab from the left. It should give a shape. NEVER buy hair without a demo anyways!