Textures vs. Lag

Dun dun dunnnnn..

The less-than-liked word 'Lag'.

Lag seems to me to be partially due to loading objects and textures. Other than scripts, how much do multiple textures in a place affect lag? Such as, if a place were to use several of the same textures rather than each thing using different textures, which would be less laggy?

Such as the first with many of the same textures, let's say 75% of the textures are the same.. just different objects. Second only has about 50% of the same texture used.

Lag is a killer, and I'm working on getting as little lag as possible in my new build. I can't do much about the SIM lag, but ensuring that the build has little as possible is very important.

Gonna go clear my cache and relog to time how long it loads in
-- WOOHOO! 10 second load time with a Radeon Xpress 200!

Yes, less amount of textures, or lower resolution textures reduces lag, but only the "rezzing" lag. So areas with less textures or lower resolution textures will become visible faster.
But, there are also numurous other things that create lag. Scripts, avatars and flexi prims to name a few. These basically create lag every time they change or act. Some of it server side, some of it client side. But, looking into textures is a good place to start reducing lag.

there are multiple kinds of "lag". Better texture management helps almost all of them. Unfortunately in public areas where everything is created adhoc it's horrible. If you are building your own stuff for a private island you can help yourself out alot by being texture frugal.

Yes, fewer textures means information that has to be downloaded to the client. Using lower-resolution textures also makes a difference.

Interestingly enough, textures impact both client-side lag and server-side lag, because the server has to send the information to all of the agents in the simulator. It means that if your sim has a lot of people teleporting in there, having a lot of textures could increase lag. Once the textures are sent to the client, they're stored client-side in the cache, so the server-side lag is a one-time hit per person when they enter the region.

But yes, in general you should try to use fewer textures, and use low-resolution textures when you do. You really don't need 1024x1024, or really 512x512, trust me. Small stuff can probably even get away with 128 or less.

If you use the same texture in a build as opposed to different textures all along, certainly, you'll save "lag" points. Also, remember to lower the pixel size on your textures, e.g. use 256x256 textures rather than 512x512 or 1024x1024. If you can use a 256x256 (or 128x12 texture and just repeat it on the surface both vertically and horizontally, you'll save people from having to download the larger textures.

One trick to use in a build is to try to make 1 texture using all or almost all the textures that you'll be using. Why make someone download dozens of 512x512 textures when you can just put all of them in 1 or 2 textures?

The faster your shop rezzes, the more likely people will stay. If I had to wait 2 or 3 minutes to see a shop, I'm probably going elsewhere.

Right, although there's a tradeoff here: assuming one has some minimum acceptable visual resolution for an image, combining them into a single texture will make a bigger texture (obviously), and bigger textures take longer to download than smaller ones (obviously)--but less time than the equivalent number of little textures.

The downside is when you have to share the image download pipeline with others: say your build uses just one 1024x1024 texture instead of sixteen 256x256 textures. Now, if you're in a skybox with no other textures anywhere in drawing distance, that huge texture will load *much* faster than those sixteen little ones. But if you're on the ground, surrounded by other builds, Linden surface patch textures, etc., etc., that 1024 may stay in the download queue for a really, really long time before any of your build is textured.

Not arguing against the idea--I do it myself--but depending on surroundings, it may or may not be a win.

Why do people focus so much on the time it takes to download everything?

If I tp to a store I'll spend less than 1 minute waiting for everything to rez, but generally at the very least 10 minutes of wandering around.

The ratio of time spent rendering and time spent downloading is 10:1 for this example so focusing on the download time seems a bit redundant, especially since optimizing texture usage for improved rendering yields a lower download time as an added perk for free.

Textures soak up system RAM and gfx card RAM too, as well as hdd performance on the cache, and even bus traffic shuffling all this around. DL time is simply the easiest one to "see" and gauge.

I'm missing something here. What does the time wandering around have to do with anything? If you're waiting less than a minute for everything to rez, that means it takes less than a minute total for everything to both download and render. How are you turning that into two separate measurements?

The downloading (& fetching from cache), esp. the image decoding sep, steals cycles away from everything else. The sooner it's all done, the sooner the viewer can concentrate on doing all the 3D gee whiz stuff at full speed.

I'm missing something too since I don't see how the time it takes to download has anything to do with lag even in the highly twisted sense people use it in SL.

I don't care how long anything takes to rez since it's always a negliable amount of time compared to the amount of time I'll spend there. I do however care about the performance I'll have once it's all rezzed and I'm wandering around.

Maybe it annoys you if you have to wait 40 seconds instead of 20 seconds before everything rezzes but it's going to annoy you a whole lot more if you get 10fps instead of 15fps because the build was inefficient or constantly rubberband/freeze because the sim is being overtaxed.

Or to use a different analogy: I don't care how long the viewer takes to start, I care how well it performs once it is running. You want LL to focus on the performance while it is running because that's how you'll be using it 99.9% of the time, not waste time focusing on shaving a fraction of a second of the start-up time.

The missing piece is that the bulk of people using SL are doing so with anemic hardware. People want to set things up so they work nicely for a broad cross section of viewers, not just the few who have better-than-average hardware (yes, yours is much better than typical). With the chipsets most users have in their machines, there isn't enough video memory to hold all that many textures, so loading isn't a one time thing. The same textures are fetched and decoded over and over, so that "startup" time never ends in a texture-heavy area.

On almost all aspects these things are in tandem not opposed. A smaller texture will both DL faster, and allow for higher fps. A 24bit texture where appropriate is 3/4 the download, and about 500% faster to render versus 32bit. The only notable exception would be compression, but in SL all textures use the same jpeg2000 once uploaded, so it's moot. Being wise about your textures helps all around.

Another side to that is why should I concern myself with users that playing SL on underpowered, underspected laptops with bargain basement graphics acceleraters and 512 meg RAM? This is not a glorified game of Pong or Pac Man. It takes better than average hardware/systems to run satisfactorily. Keep gearing SL to low end machines and SL will ramain low end.

My take is...........if you can't deal with a little more lag than someone with a better machine, then get yourself a better machine. There are sacrifices one must accept if you insist on using that clearance bargain computer you got off eBay. Why should I have to sacrifice quality for your lack of performance?

It seldom takes more than 45 secs for even the busiest area to rezz for me. And I do not have what anyone would call a gamers rig. It's just an off the shelf Lenovo Desktop with 3 gigs RAM and a 2 year old nVidia 8600GT card.

Hardware isn't relevant when it comes to downloading, your connection speed is the limiting factor there.

There's no difference in download time on my old puter with a FX5200 and my new puter. They rez just as fast, it's only the fps that makes any difference and for the "low end" of the resident spectrum specifically you want to make absolutely sure that your build is *render* efficient because even a 1fps difference can make an immense difference there.

Which is my point: you optimize because it's more efficient for rendering, download time is merely an afterthought.

You can reuse a 1 prim sculpty dozens of times and it'll be texture efficient (1 baked 512x512 texture + 1 sculpt map) where a prim version could need 4 512x512 textures. Even though you have a lower texture usage and shave a few seconds of the download time you'll have far worse performance with the sculpties.

Focusing on the download time and nothing else just isn't the right approach to reduce "lag".

And that's fine, there are all sorts of places in SL that appeal to features only a limited population can see. There are places that rely heavily on glow, for example, even though lots of computers can't display it at all.

However, the OP's question was about how to reduce the things that can get in the way, not how to ignore those issues.

You don't understand how it works. Fetching and decoding textures is not downloading. Fetching happens from cache as well, and decoding has to happen then, also.

Video cards have finite memory. All textures are not held there indefinitely. Each time the scene changes, it all has to be reevaluated. If there is more in the scene than will fit, and something different comes into view, some swapping out has to happen.

To put it another way that might be easier to understand, this is a lot like the thrashing problem that general purpose virtual memory systems can experience, but it's limited to the rendering instead of the overall system.

I understand it just fine, but the op asked a question about "textures vs lag" and a few of the answers drifted to talking about rezzing (aka download time) which doesn't relate all that well.

"Rezzing" isn't a one-time thing for a great many users, this is what you seem to be unable to understand. (and it's only partially related to downloads, once again, cached elements need to be rendered too.) For overly busy builds, that has to happen again and again during the same visit. That is why conservative use of textures and other elements can have a payoff. It increases the pool of viewers that won't be forced into those load-again load-again cycles.

Kitty is correct that there are two components: scene rezzing versus "operational" lag.

Personally, I feel that time spent waiting for a scene to rez is wasted time, and it's a good idea to minimize it. Sometimes we're actually in a hurry to get something done.

Also, most of the things that reduce scene rezzing time also reduce lag once you're in the scene. Viktoria mentioned at least one (pulling textures from cache); and another was mentioned above: if the server is busy downloading textures to lots of clients, that contributes to sim lag (e.g., reduced physics frame rates, slower responses from scripts).

Furthermore, if you move around at the location where you are, the periphery of your draw distance moves, causing more rezzing lag, and contributing to operational lag.

So, Kitty, while you're completely correct that there are two different problems, the causes and solutions are closely related, so it's not surprising that people lump them together.

45 seconds is for some people more than enough to decide to not bother with a place and move on, maybe visit it some other time. IF they even remember they wanted to check back again.. For store owners and the like, that's basically another customer lost.

And yes, it's nice to push the limits of what's possible, but at the same time, telling people to "just buy a better puter" is not an option either. This is rather common knowledge in the gaming industry already. Every game comes with options to tune down visuals to a very bare minimum, while using polygons and textures as efficiently as possible.

You don't want your potential customers to spend their money on a new computer. You want them to spend their money on your product. If a game can not run more or less fluently on a computer that was above avarage (so just under top-notch) FIVE before game release, than the game developer has effectively lost half its customer base already.

At the same time, game developers can alter their models depending on the system specifications. They can use more intensive models on higher grade computers, while skipping upto 75% of the polygons used while in "old spec mode". The matching textures are shipped with the game as well, so no download needed.

SL doesn't come with such options, at least not for things we create ourselves. They could implement something like that into avimodels for example, to use more detailed wireframes on higher spec computers, but that wouldn't be too big an upgrade overall.

Overtime, versions of SL with higher minimal system spec requirements will appear, no doubt there. Windlight is already a small example of that, but don't expect huge increases for at least another year now.

OMG! I know ALOT of people like that.

I constantly get asked "Why wont that there Walmart computer I bought run this??"

I have a friend who bought one. Since I'm always saying "replace the video card", he replaced the onboard GeForce 7 series with a GeForce 5200 PCI card (PCI, not PCI-E).

I've encountered people upset that there's no support for Windows 98 or ME, and ones who think 80 GB hard drives are "huge".

My fiancee's mother is a GOOD example of these people. Yet she still can't figure out why her 512 mb of RDRAM is 'not enough'. The salesman told her it was "the fastest". And her system shouldn't be so sloooooow.... she still has 100 MB of space on her hard drive.

It's a very basic difference in what people play this game for.........some play to shop and spend "money". But most play to have fun. If the deciding factor is speed then the user needs a computer that will deliver that speed. If the deciding factor is spending (as quickly as one can spend) then it's up to the merchants to deliver........by doing whatever they can to reduce time rezzing (lag). I assume you are a merchant from your response. So you need to do what you can to get that smaller percentage of potential customers (the ones who will not wait for stuff to rezz). You don't need to do that for me though......I'll wait the 45 seconds. And I believe I'm in the majority.........we will wait to see what we came for. And we want to see as much detail as possible when we do see it. Funny how many merchants expect people to buy or otherwise use their product yet don't feel it's necessary to show that product in the most detailed way..........I don't understand. But that's me.

And to risk be flamed to no end I want to say, if your potential customer cannot spend the money necessary for a computer to run SL in an acceptable way (and that is very subjective.......acceptable to me is not necessarily what is acceptable to Jane/Joe Blow. Unless you have some real deals then they likely will not spent a single linden in your store. No matter how "lag free" you are.

I sell nothing. I make lots of stuff. I give away lots of stuff..........it's all as highly detailed as I can make it. I take no notice of rezz time.........if someone has a problem with that they don't have to stay or take anything. Just a very basic difference of approach to the game.

These arguments come up periodocally......and the "politically correct" approach is always king. Well, I don't do it that way and won't until LL puts in place some method to prevent me from doing it my way. You will not enjoy the vast majority of SL with a low end bargain basement laptop you got off eBay at the discount price. You want the full benefit of SL you need a slightly (key word: SLIGHTLY) better than average computer. If your choice of type of computer is a laptop then your expenses are quite a bit higher......say in the 1200 USD range. But if your choice is a desktop it's pretty close to half that.

Sorry, I still have next to no sympathy for people who cannot enjoy SL with their 6 year old computer that has never seen a speck of maintenance.

Actually, I'm a builder/scripter. And although I wouldn't mind a complete free hand in prim and texture usage, it's something I keep an eye on anyway. If I build something for a customer, and the place doesn't run well because it's too laggy, then I don't want that lag debited to me. They may unknowingly add whatever causes for lag they wish themselves, but if the lag is caused by my build, then I feel I didn't deliver something properly, even if low-lag wasn't part of the contract.

I even agree with you that (for example) vendors should use the best textures available, so people get a good idea what they're buying. If I can't see the details of a sample picture right because they're all stretched, then I definitely won't buy it either.

But, the result is, that large concentrations of high res textures on vendors, for example at malls, cause so much lag that I generally wait for 1 or 2 textures to rez, and if I happen to like those, I immediately visit the main store instead, which generally has a more spacious layout, with less textures per cubic meter to load. As a nice bonus, the mainstore will generally have the complete collection for sale, while stores at malls usually only have a selection.