Sculpties affect sim performance???

Some quick background: I have 3 sims in the Havok4 early adopter program. One of these sims encountered very severe, debilitating lag immediately after coming up under the new Havok4 code. Close examination of the sim stats revealed that we were getting frequent spikes of physics lag, which coincided with major sim FPS and dilation drops (from 45 sim FPS down to 0-4, and dilation as low as 0.30). Over a couple of days, while investigating the issue, I quickly noticed a pattern. Whenever we had these lag spikes, the collision detector consistently showed that the only collisions in the sim were between non-physical 20x20x0.5 megaprim platforms and the avatars standing on them. If no one was standing on a megaprim, performance was normal (although dilation fluctuated, sim FPS and physics lag were, for the most part, normal). But land on a megaprim platform and walk around a bit, and BOOM, lag spike.

This was unacceptable for the folks who used that sim for sandboxing, so I submitted a ticket to have that isand reverted to Havok1. Well this ticket sat in the queue for over a week, and during that period, 2 new Havok4 updates were rolled out, and overall sim performance stabilized a bit. I updated my support ticket with my observations on the improvements.

AND HERE'S THE POINT OF THIS POST: A few days ago, a member of the LL Concierge team emailed me to ask if I still wanted to revert the sim, and added the following:

"Yes, mega prims do affect region performance, as do sculpties -- keep an eye out for those as well!"

Sculpties? Really? I wasn't surprised about the megaprims, but sculpties are everywhere! I can see how they would be an increased CLIENT burden because of all the polygons, but a region burden? Can anyone confirm/deny here?

I'm not going to try to pretend to understand or explain the physics behind all of this, but it's something about sculpties are "tortured prims" and the physics behind those.

I'm sure someone can explain it better, but if you're hanging out waiting for an answer, it'll help you get started.

I've heard this many times, myself, and have seen it in action.

I'm surprised about the sculpties reference. My understanding was that the collision plane for sculpties was that of a sphere or ovoid -- you can see this for yourself by making a big sculpty rock or something like that, then walking on it. Therefore, the physics for sculpties *should* be no more intensive than they are for spheres. Pretty much all the fancy visual effects of sculpties are client-side, as far as I know.

-Atashi

Well I will note this- a weird thing about Havok4 is sometimes it seems to rez avatars lower than normal, so your feet sink into any prims you're walking on. I was wondering if that's why we were seeing the physics issues, because avatars were interpenetrating the prims. I seem to have noticed more 'sinking into prims' in general with megaprims (even before Havok4) than with normal ones. Could the sculpties issue be similar, because of their crazy bounding boxes?

Sculpties give off the same amount of physics lag as a sphere.

Why? When LL added the sculpties, they set it so you would collide with just a sphere not the actual sculptie shape.

This could be a mega prim issue! Boudoir Island had this issue, the sim was crashing after the lag spikes! I had a mega prim floor "10x10x0.5" in the Kaosome Clothing Store.
The sim owner had Havok 4 removed from the sim once that happened.

Weird thing is this effect came several days after Havok 4 went live on the sim. This is weird sense magically this problem should not appear out of thin air, but that seams like Linden Labs MO right now.


Peace,
~ Soma

Well if it's related to avatar interaction, maybe it just took a few days for someone to stumble across the problem area, or move in the wrong way?

A great sculptie artist once told me--moderation in everything you do.

Oh, FFS. Why the hell did they introduce sculpties and then tell us to "watch out for them" because they affect region performance? Sheesh. The only thing that doesn't affect region performance is not logging in at all.
Textures = bad, scripts = bad, flexi = bad, too many prims = bad, too many avatars = bad, megaprims = bad.

I guess we are supposed to just hang out in empty sims and chat naked.

Your World! Just imagine it, don't actually build it!


(sick = cranky)

A problem with avatars rezzing into the prims? Raise your landing point by a meter and see if it makes a difference. If an avatar falling a foot or two onto the prim gives a different result, then you've got a big part of your answer.

in reply to [Well if it's related to avatar interaction, maybe it just took a few days for someone to stumble across the problem area, or move in the wrong way?]

No the shop was active. I had been down there myself a few times.

Oh and how dose one quote on this forum? >.<


Peace,
~ Soma

One hits the "Quote" button in the bottom right corner of the post one is trying to quote.

/me loves the easy questions.

QFT

Oh geez that is like me to overlook the obvious


But it is weird that mega prims would have such a problem.

Why???? well there is less for the Physics Engine to actually handle with mega prims vs regular prims made to the size of a mega prim. I can only see that it could be to little! and multiple avies could be hitting one vertex of the mega prims bounding box? that would be like two bullets hitting the same spot! I doubt that is the case though.

Havok 4.6 (The version Linden Lab is jumping too) is more advanced then the physics engine they use in most Next Gen Games Halo 3, Skate and Bioshock keep in mind these are games made for the Xbox 360 and they all use Havok 3!

Keep in mind there is some crazy huge things in Halo 3 like giant walking bugs that you can land a plane on, and much much more!

Peace,
~ Soma

This is why I laugh all the time when club owners complain about lag, then you look and see their dance floor is all megaprim. Well duh! You have 20/30/40 avatars all colliding with -one- prim. The physics engine needs to run those calculations constantly to do its job of keeping the agents from falling thru the floor.

Less laggy dance floor? Flatten the ground, rez a phantom'd megaprim and move it as close as possible to ground level. Agents dance on the default ground, but you have your swirly floor for looks.

To remind myself not to build laggy things out of megaprims, I rezzed each one in my collection out, set Phantom, then Take'd it back and deleted the original from inventory. In fact, set -everything- phantom unless it absolutely can't be. You hear that, no-mod furniture vendors!?

well all of this makes sense..i've heard that there is no texture lag persay on a sculpty because there is one texture being rezzed but at the same time i've started builds in lag free sims and used more tha n ten sculpties and all of a sudden people started complaininjg about lag..I had suspected it was the sculpties but never could really prove it.

As far as that person saying everything in moderation..this kills me..sculpties weren't introduced as moderation items..they were introduced as a resolution..weren't they?


When are we going to get a resolution to one problem without that resolution causing more?

~Lana Tomba

I think you mean NURBS, not POLYGONS...Polygons get destroyed and turn to blobs in this nurb invironment.

Ya, you're right...it can be annoying. But understand this is why professionally made games are so hard to optimize--there are many rules game designers have to follow, so that it runs well on all systems.

LL gave [us], the gamer, the ability to create our own game world...it is our responsibility to keep things optimal...if we can't handle this responsibility (which it seems the majority of sims can't), then we can't complain about performance.

No, sculpties were not a resolution...at least not completely--they weren't just created to lessen prim count, they were also created to give us the ability to make organic and unique shapes.

The game engine still reads sculpties as triangles--if you use too many triangles, things slow down. No matter whether you use NURBS OR POLYS, everything gets converted to triangles when rendered. (FYI--sculpties are not NURBS, they are still Polygons)

That doesn't appear to be true. When I view a sculpted prim that I made in wireframe mode (I think SHIFT-CTRL-R?) the polygons shown are very nearly if not exactly the same as they were in my modelling program.

I wonder if Havok4 sims are trying to actually create a collision mesh for sculpties, for "enhanced realism". At least, I know that Havok is capable of using trimesh for collision rather than just simple collision primitives, though I doubt that LL would ever do that. But that's the only way I can see sculpted prims causing significant physics lag of the kind mentioned in the OP.

Very True!

If all residents followed a game design path it'd be less laggy. In various games like Unreal Tournament where you can design your own levels, the lag or lack of, is a sign of someone who knows what they're doing

Also we'd have more empty sims since studying all this stuff takes a while and causes many headaches.

thats my point...reduce prims..reduce prim faces having to rezz textures..reduce lag?...oh..no..well scratch that..our solution has a loop hole in it..if you create a scuplty with too high of a polygon count then eerp..it's the same thing as 100 little triangles

It's all confusing to me

~Lana Tomba

Aha! The naked chick in the other thread was just trying to improve SL's performance!

I totally agree, but some actual guidelines on optimization would be nice. Coming out with a prim type that allows (finally!) organic shapes to be easily created and then telling people who create organic builds with that prim that it will nuke their region performance doesn't exactly help. The best we get in terms of suggested load comes from resident observation, wild guesses and assumptions that people pull out of their butts. Where is the threshold on number of flexi prims before performance degrades significantly? Where is the threshold for scupties?

Leave it up to sim owners to figure that stuff out and BIG SURPRISE, many get it wrong.

Either way the sim has to make those calculations. 4 regular prims or one mega prim, they still have the same amount of collisions per avatar. Only difference is the amount of objects in play, not the amount of calculations.

oh and sculptie prims tend to use more textures then other prims. why? well there is only one face on a sculptie so you need to have one well made texture made just for a sculptie! this texture would for the most part only work on the scultpie it was made for. So instead of using one texture over and over you need a a custom one per sculptie.

Everything needs to be done in moderation! why did linden lab put in a 15,000 prim max per sim? well multiple reasons

1. to many prims creates horrible client side lag, having a limit helps stop a majority of stupid Residents from over doing it and creating a mess. Yeah Linden Lab is saving people from them selfs.
2. The limit is based on the fact the prims take sim resources.
3. I am sure there are others

I do agree with Michael Bigwig on how this is a world mainly designed by rookies and noobs and there are limits in place to save people from themself.


Anyways if you want to really know more go to school or search the interwebs I rather not exsplain it.

Peace,
~ Soma

Roger that...

However, it doesn't take a graduate of Full Sail to realize packing a sim full of as much garbage as you can doesn't promote healthy performance--especially if you get higher traffic counts. Not to mention, there are still a lot of people that use unrecommended texture resolutions throughout their builds. Also, people should realize every unique texture has to be rendered separately by the engine--so a sim full of garbage, with a bunch of unique textures will put the smack down on the game engine, and your hardware.

These are a few simple rules that any cg artist should learn from the get-go.