Second Life Mesh Meeting Update Week 26

Mesh cost is still an annoying topic of conversation. It is still undefined. But, we are getting closer to a cost and we are learning more about the reasons for the costs. The Lindens are definitely being more open about the Linden costs. That hasn’t done much to improve the manners of residents participating in the meetings. 🙁

Mesh Meeting

Mesh UUID Swapping

This subject keeps coming up. Kyrah Abattoir  asked the question in a new way. Quoting, “Figuring out a sane and conservative way to implement “set by UUID” for Meshes, builtin delay by link set for example, to prevent excessive mesh swapping/animating attempts, yet allow loading and unloading a mesh for legitimate uses. It seems to me this question assumes a swap can be done and that it is frequent swapping that overloads the sim. Originally many hoped that mesh could be animated as sculpties are.

Nyx Linden tells us that the technical reasons are many more than just the mesh animation case. Changing a mesh, even in a link set, creates server instability. Once rezzed, a mesh changing creates problems. De-rez it and rez another is possible but likely to be a lag producer. Rezzing mesh clothes and attachments is not likely to be much of a problem. De-rezzing a building and rezzing a new one may be a significant problem. I suppose we’ll find out.

Whatever the case, it is not going to be possible to change a mesh UUID after it is rezzed. Runitai Linden tells us it certainly is not going to happen in the near of far term and is unlikely to ever happen.

Mesh Lindens

Current Mesh Priorities

The priority is only what’s absolutely necessary to get the basic functionality out the door. Right now that is mostly the cost equations and cost value tweaking along with stability.

Physics Type

As one starts to deal with mesh the physics type of None is tempting to use. After reading the mesh cost information it is intuitive that a non-physics object should cost less prims. The problem is that a non-physical type cannot be the root of a link set. Also, and I’m a bit confused here, an object can’t be a type None. The Linden system has to have a type so the viewer knows how to render it and the physics engine knows what to do with it. Having a type None that one tries to make physical is apparently a problem. So, if you are having trouble with Type None meshes, don’t be surprised.

The Lindens are going to try and get Falcon Linden to give us a better explanation of this aspect of building in SL. I’m sure I’m not clearing things up as I remain confused.

Sculpties Suddenly Failing?

Drongle ran into the problem and asked, “Will the new sculpty normalized triangle area limit be increased so that my ladders (and potentially other existing content) are not destroyed on release?

Runitai Linden tells us that this is a bug in the viewer. One version of the Beta viewer is already in the tube with the bug and is likely to make it out the door. The problem will be fixed in the next version.

I think the bug is currently only visible in ADITI. The problem with the sculpty is complex. The result is the sculpty never rezzes or only ever rezzes as a sphere. Nyx Linden says it stems from some sculpties having a massive amount of surface area, which creates bad performance and stability problems. A change was made to improve stability. Unfortunately that broke some existing content. They think they have a fix to accomplish their goal without breaking content.

See: Broken Sculpty

Mesh Use in Vehicles

With some of the UUID swapping issues related to mesh Bunnie Mills was curious how mesh would work in vehicles. Nyx Linden answered, “Mesh vehicles should perform just fine, if not better than prim vehicles.

In regard to region crossings, there should be no problem.

Avatar Joint Names

CTS-660Changing DAE skin names causes weird behavior – There is some concern about joint names and modeling tool names in the DAE files. If the file name or the authoring tool changed some saw results change. The Lindens tell us that name interpretation does not change with file or tool name.

See: SH-1926

Prim Equivalence Plans

People are proposing new plans for how Prim Equivalence/Resource Weight should be figured. At this late date, it is simply too late to adopt a new plan. It may be possible to change the plan at some point in the future, but don’t bet on it.

The new idea that scripts in mesh will cause a cost increase has upset many. In relation to that, a new concept is coming into use; static and dynamic mesh. A static mesh does not have a script nor is it physical and a dynamic mesh has a script or is physical. Basically a mesh that is changing because of a script must communicate that information to other objects, the physics engine, and all avatars in the area. It places more load on the server and that incurs a cost.

Some are complaining that mesh objects and mesh attachments are not being treated equally in relation to prim and sculpty attachments. That is true. Nyx repied, “We haven’t gotten to a point where we’re ready to do a better job of limiting avatar complexity yet.” Think about that word yet…

It is becoming clear that some of the apparent inequalities between prims and mesh are a matter of legacy. The Lindens are making changes and doing things differently now that they know more about how virtual worlds work and where the bottle necks are. The mistakes… (mistake is not a good word here but…)  made in costing prims are not being repeated with mesh. However, for now these changes will only affect mesh. Otherwise, too much content and tier costs would be affected.

Single Mesh Object Cost

As things are linked together object costs start to get confusing. Gaia Clary asked, “Why is the Server cost of the first mesh object 1.5 instead of 1 only ? (Why can’t we make meshes with PE=1 ?)

Nyx said, “There’s an element of server load that is per-linkset (object) and another part that is per-prim. So a single prim object has both costs. The [minimum?] numbers currently are 1.0 per object and 0.5 per prim.

Runitai, “If it’s part of a link set, one of the individual meshes will cost less than one prim, but there’s overhead associated with each “object” (root prim) and by “will” I mean “can”, if it’s simple enough.

Gaia Clary, “I only want to understand WHY. Nothing else …

Nyx Linden, “Because that’s what our overhead is quite frankly 🙂

Runitai, “The rez pipeline has to load meshes from the asset server, which is something it doesn’t have to do for prims. There are also complications around the physics data that are different from prims. Frankly, a lot of these accounting changes are things we’ve wanted to put it in for a long time but couldn’t because it would break legacy content. The number of bytes to be fetched is significantly higher even for the simplest of meshes.

Sculpty accounting has no basis in reality. Also, texture accounting has no basis in reality. Nor does script or attachment [accounting have a basis in] reality. The new accounting [system] does.

I think it is obvious that mesh cost is never going to be a true equivalency to prim costs. Because this conversation reveals the Lab’s recognition of the past disconnect between prim cost and the cost of providing the resources, one can expect all things to head toward changing that disconnect.

Making a sudden change to prim cost and tier cost would be suicidal. To make a connection between current charged cost and actual real cost may be a reasonable goal. But, it is not going to be politically acceptable in SL. So, some other approach has to be taken.

Something New Coming

The Lindens drop hints here and there that new things unspoken are coming. We are seeing blog posts here and there discussing what those things might be. I think the disconnect between charged and real cost may offer more insight into what those things could be.

It is going to be highly objectionable to residents to raise the cost of existing prims. Many of the amazing builds in SL are already leaving because of tier costs. Mesh as a new feature is going to be based on a more realistic cost system. Some means of getting more features associated to real cost is likely. So, will there be new features like Voice with monthly charges? Will there be new ways for residents to earn a living? What can they add that will bring more money into SL?


This week we learned more about mesh and the costs associated with mesh and how it is provided. There were no big announcements. No new features. We are down to the immediate bug stomping and should soon start to see mesh arriving in the Release Channels.

One thought on “Second Life Mesh Meeting Update Week 26

  1. I just wanted to say thanks for doing these posts. I try to follow what goes on in mesh, but as always it’s pretty much just the dedicated insiders who know what’s going on.

    My current thought is that “bad performance and stability problems” is Linden code for “our priority is to generate revenue, not empower creators”. Along these lines I think that LL needs to make up their mind, either charge people to rent land or charge to upload content, but not both. I for one will not tolerate any more of their shenanigans.

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