Shooting LL’s own foot: why meshes will not be a huge immediate success

It's a sculpty!

So now you’ve bought your first meshed dress and/or avatar and are generally excited about the bright new future that meshes will bring. Well, after you persuade your friends to switch to a mesh-enabled viewer, of course; thankfully, even the non-LL viewers are all starting to include meshes (yes, even the ones based on SL 1 :), so I guess soon everybody will be seeing meshes in all their glory.

At least on avatars and avatar attachments. Buildings and furniture is a completely different story!

Why? Because Linden Lab, as usual, has shot their own foot. Their formula for “prim equivalents” — how many prims an uploaded mesh will  use on a parcel — is so weird and complex that the results are an absolute mess.

Let’s take a simple example. Long time ago, I uploaded a sculpty of my own head. There was a tutorial somewhere to explain how to export your avatar as a mesh, tweak it via some crazy software (I wish I could remember what I’ve used), and get the equivalent sculpty. SL avatars are not insanely huge in terms of polygons (about 7,500 triangles for the full mesh, I think — more than many MMORPGs, but not that complex), and since sculpties can become 4096-triangle meshes, they will fit fine in three sculpties. So I did just that for fun. And of course, as you know, a sculpty just takes one prim. So long as you can fit the mesh inside 4000 triangles or so, it’s a reasonable compromise. The problem, of course, is that few 3D modelling tools create flawless sculpties easily — it’s very hard for an amateur to get them “just right” with a simple 3D tool.

I have kept that mesh around, though. So now I could upload the mesh directly. Here is the result:

Meshed head. 6 PEs at the size of around 0.24 x 0.20 x 0.25 m

Hmm. Note that it’s the same mesh as the one used for the sculpty, but it actually looks nicer (well, or it would, if I didn’t have it selected). The trouble is, this now takes six prims instead of just one!

Of course, if you have been tweaking with the mesh upload controls, you know that you can optimise this a bit. For instance, I might be able to delete some triangles, or even upload a very, very simple physics model, which would reduce the amount of prim equivalents. Expert modellers know how to reduce meshes even further by tweaking with the mesh on their 3D modelling application, and eventually compensate the lack of triangles by using cleverly designed textures on top of a simplified UV model. So I guess this would be enough to get the mesh down to just one PE — after all, if this is pretty much the same as a sculpty which only takes one prim, you should be able to upload the same mesh and get just one PE, right?

Wrong. My friend the artist Scarp Godenot, pointed out to me that LL got the equations all wrong. Namely, the amount of PEs change with size. The tests I did were for insanely huge meshes, so they were already so big in terms of PEs, that I didn’t notice any difference at all in PEs. But I knew I was using highly unoptimised meshes.

This one, by contrast, is very simple — probably some 3000 triangles or so. Less than 4000, in any case. so see what happens when I start resizing it:

Size is now 0.65 x 0.54 x 0.29. But PE has grown to 13!

What happened?! Well, this is extraordinary: the amount of triangles remains exactly the same, and remember, it’s the number of triangles that make the difference. But now this mesh is a bit larger than twice the size… and LL now thinks it should “consume” 13 PEs instead of 6!

When Scarp told me about this, I was very, very skeptical. You see, there is supposed to be some logic to PEs. Mesh size — the amount of polygons — is what makes a difference to the rendering engine, and the size of a mesh is usually the amount of polygons it has. The actual virtual size in meters makes little difference. Well, perhaps a bit, if you consider how occlusion is calculated, but the algorithms for that are hardly easy to predict what works best. For instance, rezzing a huge mesh near to you might mean that there is a lot of objects occluded behind the mesh, but, on the other hand, after figuring out which ones don’t need to be rendered every frame, it means the graphics card will have less work to do. On the other hand, shading a huge mesh might take a bit more time than shading a small one; but, again, if you have just one huge mesh filling the whole of the 3D viewport, the renderer will not need to worry about shading the remaining objects — they will be out of sight anyway. So it’s not so obvious that a mesh with large triangles will take more time to render than one mesh with small triangles. It all depends on what’s on the background, the lighting, and so forth.

But all that happens client-side! So why should the amount of PEs actually grow if you have a mesh that is twice the visual size but has exactly the same amount of triangles? Remember, you can resize a sculpty as much as you want, and it will be always exactly one prim; the same happens to Linden Trees as well. In terms of server resources, it makes no difference whatsoever.

Well… perhaps that is not entirely correct. You see, a mesh will interface with Havok beneath. The more virtual space it takes, possibly the more calculations Havok has to make. With sculpties, LL has pretty much ignored that. With meshes, however, objects pay a huge penalty! In fact, it looked like half the cost for PEs would come just for the amount of resources consumed by Havok, which is exaggerated… but possibly makes sense for someone at LL.

So, well, an object twice the linear size (as measured on the X, Y, Z axis) consumes twice as many PEs. That makes sense… or perhaps not. In terms of volume, it’s eight times larger (2 to the power of 3). So that was a bit confusing and unexpected. Hoping to figure out what was going on, I resized the head mesh even more:

Size is now 3.5 x 2.9 x 3.7 — 15x the linear size, over 3000 times the volume — but PE is now suddenly... 7?!?

What’s going on?? The mesh has now grown: over 3000 original meshes could fit inside this new mesh, the volume has grown quite a lot. But now the number of prim equivalents is just… seven! Now that doesn’t make any sense whatsoever. Scarp has told me that sometimes the number of PEs is not immediately calculated, and he’s right, sometimes there is a short delay. But in this case I waited a long time and the numbers didn’t change!

I was expecting this to be at least a PE of, say, 90. The theory was: something twice as large linearly (i.e. along the axis) has twice as many PEs. So since this object is now 15 times the linear size of the original, it would make sense to consume 90 PEs. Instead, it consumes little more than what the small object did! Why?? I have no clue, so I made the object even bigger:

12.63 x 10.5 x 13.3 m — or 140,000 times the original volume — but PE is "merely" 38

This is about 3,6/3,5 times the linear size of the previous object, so apparently the “rule” works well again. However, this is over 50 times the linear size of the original object — and that would mean that if the rule had any logic, it would have, say, a PE of 300!

So… well… it’s clear that the algorithm is not linear but a very strange curve. My last example:

39 x 32.47 x 41.18 — a volume 8 million times bigger — but PE is just 82

This final example has three times the linear size than the previous one, but the PE just became twice as much. Compared to the original object, however, this is 200 times the linear size (8 million small heads would fit inside this object). So, clearly, the algorithm is not linear — not in the linear size, and not in the volume. It seems to be a logarithmic progression, but there are some anomalies. They might be explainable with the way Havok deals with objects: perhaps there are a lot of tradeoffs for very small objects (which tend to be very penalised) compared with huge ones (which Havok might deal differently and thus the “weight” of the physical aspect of the object matters little). So this means that a 3D modeller uploading a mesh will have to find the “right” size for the upload: not too small, or it will be over-penalised by Havok (assuming that’s what causes the anomalies shown in the images above), and not too big, or the sheer visual size will also penalise the algorithm.

As a conclusion… this means that meshes are pretty much worthless as building elements. If such simple elements, which can be done with a single sculpty, take so much PEs… nobody will want to buy them. Since the algorithm is very strange, it will require a lot of trial-and-error to get the minimum amount of PEs for a particular mesh, and that requires a 3D modeller spending a lot of time (and money!) uploading meshes until they get an “adequate” PE. “Adequate” in this context means: at most as many prims as the equivalent object done with sculpties, for the same amount of triangles. However, since the final size of the object matters so much, I’m afraid that except for some very specific cases, it will never pay off: you’ll always be better off with a clever combination of sculpties and regular prims instead of using a mesh.

I don’t know if this is deliberate. Attached objects to avatars clearly are differently handled: I’m assuming that for Havok’s sake, there is little difference between a naked avatar and one wearing a 150,000-triangle mesh. So fashion designers and avatar creators will be happy, since they will pretty much have no constraints on their creativity — and meshed clothing, even this first generation, looks awesome — specially when sitting down!

Vehicles might also work well… I read that the trick is to keep PE to less than 32. Well, it’s still a constraint, but possibly it allows more effective modelling than using sculpties, I don’t know. People have certainly come up with nice designs, although I see little difference — from the pictures! — to sculpty-based designs. I’d have tio buy one and test it!

But buildings… well, definitely they will just be a “novelty” for people who have whole empty sims, but the common user will not really be able to afford a meshed house with meshed furniture… which might take 500 or 1000 PEs and don’t look that much different from a primmed design.

I think it’s important that LL reflects on how they will tweak the algorithm in order to make it usable. I think that the major problem in the past year of testing is that people have just uploaded meshes to empty sandboxes. I’m also to be blamed: all my own tests were made on relatively empty sims, and for the purposes I needed those meshes (small machinimas), the amount of PEs was pretty much irrelevant, and was so insanely huge in any case, that I didn’t bother with the algorithm.

But now meshes are out in the open. People are actively selling them — mostly as avatars and avatar attachments and a few vehicles, for obvious reasons. Builders, furniture makers, and other decorative elements — as well as artists — are kept out of the whole mesh economy. Is this deliberate for some reason? Only Linden Lab can answer that. Perhaps they really don’t want a meshed world — just better-looking avatars.

Note that there is a simple (well, relatively simple) alternative to the current prim-based economy: use a triangle-based economy instead. The problem of dealing with resized objects would still continue, however. Unless LL reviews their crazy algorithms, that will always remain a huge issue. And even the highly-inflated PE even for simple meshes is a huge deterrent — only the most sophisticated 3D modellers will be able to tweak their meshes in order to get low PEs, and, by doing so, might get their meshes at such a low triangle count, that it might be better to simply use a sculpty instead…

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About Gwyneth Llewelyn

I’m just a virtual girl in a virtual world…

  • This is fascinating and I’m thinking that really, it’s the LL strategy with mesh that’s the key, and I guess we don’t really know what that is is detail. But if I were in the Lab right now I’d have all my energies focussed on working out exactly what is going to get and keep more people inworld and what aspects of the total SL experience they might be willing to pay for. Maybe their research is telling them that is more about avatar appearance (as you yourself speculate here) and that they don’t believe mesh can add as much value in terms of the average user experience when applied to buildings and furnishings. Thanks for this insight, Gwyneth

  • Mesh currently isn’t ideal for everything. PE can be confusing, but providing a model *is* optimised, then there are certain areas where mesh needn’t be any more than its prim cousin: I’ve seen mesh houses, complete with floors, doors, windows. stairs – with PEs of between 52 and 300 (easiliy equivalent to prim builds). Point of fact, I’ve been in an *completely furnshed* house on the Main grid mesh sandbox (before it poofed) that came-in at a PE of 452 – that was house, all the lounge, kitchen, dining, & bedroom furniture (2 bedrooms), plus all doors, windows, stairways, balconies. That’s actually only 9 “prims” higher than my current prim-built house and furnishings.

    Vehicles benefit as well, as they can have a very detailed mesh, as so long as the *physics* weighting doesn’t exceed 32, they are perfectly drivable. This means an end to the 31-prim limmitation to building cars or building vehicles with complicated linking scripts, etc. Again, I’ve seen vehicles in mesh that have a physics weight of 32 and a PE of 50-70. While the latter might sound a lot, one needs to offset this against the fact that many car builders will produce *two* variants of their vehicle: a 31-prim “low detail” version for “driving”, and a high-prim (100+ prims) for “showing off” – ergo a mesh vehicle *can* offer extraordinary value, if one wishes to deive it around and leave it rezzed and parked.

    Of course, the downside to this is it’s very easy to get a beautifully-detailed care in SL with a physics weight of 32, but which has a sky-high PE.

    Worn meshes are deceptive as well – with no deformers, they cannot be resized to a great degree but, on the slip side – they *don’t* impact land prim counts in the same way as worn prim attachments do.

    Getting the right PE is a bit of a pain – and LL are working on improving things in that area in terms of the uploader. Really, the trick is *not* to extensively resize an object in-world (again, this shouldn’t impact things like houses, cars, vehicles). Not should one add a mesh to a linkset – as horrible things PE-wise can happen.

    Mesh imtems can also be tested and tweaked without incurring repeated upload costs :).

    Scuplties and mesh are also something of an unfair comparision when it comes to the server load. As Charlar Linden commented at SLCC, a sculpty may only register in the viewer as “1 prim”, but it’s a kludge, and the physical load it places on both server and viewer is significantly greater than than of a prim – LL have simply “absorbed” (as it were) that fact up until now. So in this regard, the playing field is not really level when someone says, “Oh, this mesh has a PE of 9, but this sculpty is only 1 prim, so it’s better”; it may be better from a prim count PoV – but from a performance standpoint? debatable.

    I started as a cynic when it came to mesh objects; over the last 3-4 months I’ve become more convinced that – while the implementation isn’t the bees knees of mesh object support, and while also not denying the limitations and issues that do still need to be addressed (see the aforementioned comments on deformers!) – mesh *can* have a place in Second Life, and *can* work with out any great “loss” to people’s prim counts.

    And equally importantly, mesh creation is not going to be suited to *every* market sector in SL for a goodly while – if at all in some areas; but that shouldn’t stop it entering popular use in other areas (such as those I’ve mentioned).

    It’s not going to happen overnight (remember sculpties took a year to really come into widespread use, and when through something of a metamorphosis along the way from their original implementation). We have at least one “non trivial” (LL’s own words) mesh object support update coming down the track – possibly later this year – so I wouldn’t discount things just yet.

    Really, what it comes down to – as with so much – is user education. If a content creator is prepared to put in the effort, they can yield positive results. It’s a case of understanding where and how mesh can best be put to use – and its a case of the users understanding what can and cannot be done with mesh objects.

    The first of these issues is really down to content creators themselves – although LL should be providing clear, concise and honest guidelines. The latter two: identifying areas where mesh is “weak” and educating the user base as to the limitiations, etc., I would suggest *is* more something for LL to get involved with – and in this respect, I really do not think they’ve done enough, and *that* is what could easily cause a backlash of sorts.

  • Scarp Godenot

    Clear analysis Gwyn, good job.   After discussing this to death with several of my more techie artist friends and acquaintances,  it has become clear that complicated meshes for art will be severely limited.   Limited to those occasional big name artists who can command sim level resources.  But then only temporarily.

    The dream of big time realistic immersion, such as with a fully realized sim sized mesh forest for example,  will never be seen under this Prim Equivalent structure.Also, and as we artists have learned over the years,  most art buyers simply will not purchase an art piece that is over 30-50 prims or so because they treasure their meager prim budgets on whatever parcels they happen to control themselves.  The bottom line is that most artists will stick with prims and sculpties for now and that idea is spreading rapidly among the SL art world.
    It has been suggested by some that because Linden Lab has not charged any increases  for sculpties or more complicated prim structures in the past, that they are attempting to ‘reclaim’ some system resources by reducing the overall quantity of polygons per sim across the grid.  Sort of reducing the number of prims without calling it that. Is this just paranoia?  Maybe, maybe not.I guess my rambling point here is that from my artist’s perspective,  the future is not yet here.  Mesh as mainstream art is still down the road.   Hopefully not too far down the road…..

  • Jacek Antonelli

    According to Nyx Linden, the prim equivalence is meant to reflect the resource usage (e.g. bandwidth costs) required by the mesh. A large (prim size) mesh object can be seen from farther away, and it uses a higher level of detail than a smaller mesh at the same distance would. For example, a 64m mesh viewed from 128m away might send the highest level of detail, while a 5m mesh viewed from 128m away could send a lower level of detail without looking bad, and a 0.1m mesh would not be visible at all so it wouldn’t have to send any data.

    So, since large mesh objects have to send more data to more users, their prim equivalence value is higher than a smaller mesh object’s would be. Again according to Nyx Linden, the “prim equivalence” of sculpties and normal prims is out of balance with their true costs, but LL decided (rightly, IMO) that it would be a bad idea to tweak the prim/land economy (which I guess means lowering parcel prim limits) to fix that balance. Instead, they are just trying not to make the same mistake with mesh.

    In the future, Linden Lab could adjust the equations to lower the prim equivalence. But, people would be quite upset if LL had to *raise* the prim equivalence of existing mesh objects. So, it makes sense for them to err on the side of the prim equivalence being too high at first, then lower it after they have some data about how mesh is used “in the wild”.

  • Hmm 🙂 I’ll take your word for it, Jacek, since you’ve got far more knowledge than I have on the subject. But now that you’ve given Nyx’ explanation, it almost sounds as if LL is not covering their costs properly… 😉

    Without taking a look at the code, I cannot say if meshes aren’t simply streamed like every other asset, and, in that case, eventually all sizes will be streamed. Then again, the higher bandwidth costs due to several people being in the same sim would only make sense if several people were, in fact, in the same sim. In that case, PE would go up if the number of people increased in the sim, which makes little sense — “taxing” popular sims just because they have an increased cost in terms of resource consumption.

    On the other hand, a properly designed sim with lots of meshes to avoid prims would lower resource consumption — just one mesh would need to be sent, instead of thousands of individual prims; and meshes use less textures (in theory, one per texture) unlike prims. Of course LL could argue that textures get separately transferred and are easy to cache — but so is a mesh.

    Also the reasoning behind Nyx’ argument is not totally clear in terms of relationship with the PE algorithm. Using the argument “a large mesh will require more bandwidth to be consumed because more people will require to download the highest resolution” would then mean that the algorithm would assign increasing, linearly growing PE numbers to meshes that are larger; of course there is a threshold for each LOD detail to be sent, so it might not be a smooth linear curve, but one having “steps”. But that’s not what my tests showed, with a very simple mesh: at certain sizes the PE number goes unpredictably down — or at least grows so little that it’s barely perceptible in the overall computation. So the algorithm is clearly very convoluted — while determining actual resource usage as Nyx proposes ought to be much more deterministic and easily calculated.

    My guess is simply that for some reason LL does not want many meshes rezzed in-world, although why they pose no obstacles to avatar & fashion creators is beyond me. I guess they assume that most meshes on most avatars will be so small that only the lowest detail will be sent in 90% of all cases or so.

    And my second guess is just that the person designing the PE calculation is part of the team who created the ARC algorithm and similarly nonsensical formulas that LL is so fond of using, and Nyx is just trying to find a semi-rational justification for doing it that way 🙂

  • Well, I don’t understand that. If the PE cost is absurdely high, nobody will create meshes for buildings & furniture, because only a selected few will be able to afford rezzing them — so there will be a tiny market for them in any case. Thus, most rezzed 3D content will just be prims and sculpties. How will LL benefit from that?

  • Unless LL starts to “tax” sculpties with PE, sculpties won’t ever be replaced by meshes. Sure, LL is “absorbing” the costs of resource consumption, but who cares about that? All we care about is how much tier we need to pay to display what we want to have on our parcel 🙂

    If LL starts taxing sculpties and tortured prims (which also have very complex meshes with very high triangle counts!!!), it will be the end of content creation in SL. Unless, of course, LL is planning to reduce tier cost dramatically. Hmm. That might work!Thanks for the explanation about the vehicles: that makes far more sense if it’s implemented that way! A 100-PE-car will definitely look much more nicer than the equivalent 31-sculpty car, so that at least makes sense…

  • I have a terrible example to give 😉

    Smoking is socially unacceptable, so what do governments do about it? They tax smokers heavilly. That way, three things happen: first, the overall number of smokers goes down (which is a good thing in terms of public health, of course). Secondly, governments get more money from “hidden” taxes which are not universally paid (so in a sense they’re unfair; but one can argue that non-smokers are e blessing for public health systems, so it’s fair that they don’t pay as many taxes as smokers); thirdly, and this is something I find very unfair, only rich people can afford to smoke.

    Now this is the model that currently applies to mesh usage in SL. The overall number of rezzed meshes will be small, as few people can afford rezz large meshes with high PE count. Some will tier up, and LL will earn more money that way. But ultimately, only rich people with huge parcels or whole sims will be able to fully enjoy meshed buildings. That’s highly unfair.

  • Scarp Godenot

    Whatever mesh objects are out there rated at higher prim equivalency numbers than actual extra server costs, will subtract from the other number of prim objects in that particular area,   Thus effectively reducing the server costs in the region.   Take this across all 40000 sims and there will be a reduction of resources.  

  • Nalates Urriah

    Oh… you so need to listen to Charlar’s audio explanation of PE.

    PE will eventually change to something about resource consumption. Then it will make more sense to people. 

    In general I find I can make things that use up far less of the prim limit than I can with just prims.

  • Ah yes, that makes sense, Nalates. I’ll be happily waiting for the change 🙂

    It’s good that you can generally make things use far less prims with meshes than, well, “just using prims”. Not all 3D modellers are so good as that, though. Also notice that my comparison was more with sculpties, which are, to all purposes, meshes with limitations — but no PE limits!

  • So your idea is that LL wants not only to force people to increase tier to be able to see those lovely meshed objects, but also that, in general, all fully-meshed sims will consume far less resources (and be much more empty!), and thus improve the overall grid performance. Hm! Well, both make sense from the perspective of LL, of course.

    What about the perspective of the residents? 🙂

  • SignpostMarv Martin

    The problem with switching to a triangle-based economy is that an unmodified prim cube has a max. 108 triangles, but an imperceptibly tapered cube (0.01 in x-axis only) has a max. of 8 triangles. The reason I’m told that there’s such a high number of triangles in an unmodified cube is due to needing to make vertex lighting (LL viewer doesn’t do per-pixel lighting, I’m told)

  • We’re all so used to thinking in terms of the individual object “the prim”, the “sculpty” – and from a physical level, you’re right, people *won’t* care about the “aborbed” cost in terms of server / Viewer load per prim or sculpty on an individual basis. Nevertheless, it does have a bearing in terms of the great boogieman of the grid – lag. *IF* (yes, it is something of a big if right now, I admit), mesh works out as hoped, the difference will be felt in terms of the reduction in the amount of lag people experience – and this is where the playing field between them is equalised.

    What I find amusing is that – in typical fashion – people assume that PE will *always* be higher than prim counts in non-mesh equivalent objects, and only the horror stories get touted “OMG!! It takes 600 PE to render a single tree!” – and so on.

    Very little is ever said about the lounge suite that comes in with a 32PE compared to the equivalent prim / sculpty lounge suite in with the sofa *alone* has a prim count of 34.

    Next to nothing is said about the beautifully-detailed houses, complete with windows, doors that open and close, etc., that weigh-in at 50-100 PE. – more than equitable to their prim-based cousins.

    Again, and to repeat – I’ve walked through a mesh house with mesh kitchen & furnishings that between them had a total PE of 452. That compares to the prim count in my current house (with furniture) of 443. Not really much of a difference there.

    And why are arguments against mesh always presented ias either/or? The implied idea that you can only use mesh OR prim objects?  That if you have a mesh house – by extension you must have mesh furniture?

    – Even *if* it were true that mesh was unsuited to making furniture with a “low” PE, what is to stop someone having a mesh house and prim furniture?

    – Even *if* it were true that mesh is suitable for “large” objects with a “low” PE, what is to stop people having a prim house with mesh furniture.

    Mesh isn’t exclusive – yet so many of those critiquing it seem to treat it as though it is – it is complementary.

    Hence why I said in my original comment – mesh may not be suited to *some* areas of content creation – at least for the time being – just as prims and sculpties are suited for certain uses when compared to one another; but that doesn’t mean that on the whole mesh is fatally flawed.

    Where you have hit the nail on the head is at the start of the article: mesh won’t be immediately “huge” on the Grid – and if I’m honest, PE does play a part in that – but only a small part.

    The bigger reason why many aren’t throwing themselves into mesh content creation *isn’t* because of PE per se. It’s because of the vast new learning curve that one needs to go through outside of SL in terms of learning to use Wings3D, Blender, Maya, or  whatever one’s pocket can afford. I know that has been a major stumbling block for me, as I’ve simply been unable to bend my brain around Blender – but I can bang prims together.

    So there is for many in the content creation arena the double issue of overcome one’s own unwillingness to learn to use a new tool *and* learning to use the tool effectively – and this as much as anything else is contributing to the perceived “lack” of mesh products in some quarters.

  • Thanks for this analysis, Gwyn! Somehow, though, until Linden Lab sees a clear and present “it doesn’t work / people aren’t using them at all” for an extended period of time, things won’t likely change. If this is what we have to work with, I imagine this is what we’re just going to have to settle with.

  • Deep Semaphore

    Hey Gwyn,
    my experience with mesh has been a positive one so far. I actually find it easier to build with external tools and the PEs are not that bad especially for complex objects. I uploaded a whole human skeleton and some anatomical organs recently and the PEs were quite low. Actually I also remember creating a cube with very smooth edges with had a PE of less than 1, was like 0.5 … so while I do not understand the weirdness of the PE calculation in the back end, so far so good.

  • Let’s hope it remains that way, @9b1fb3619d05f45ee404e6f37e5e60b5:disqus 🙂 Oh, btw, I do enjoy the plethora of 3D tools out there which allow quick and easy creation of meshes. For example, I never managed to create one sculpty “from scratch” — all I could do is follow incredibly complex (for me) tutorials to pretty much reproduce what others gave as examples (that’s how I got the sculpty mesh for my head, and I don’t even remember how I did it…). By contrast, one can create meshes pretty much with everything. I’ve even used Photoshop with good results!! That’s the huge advantage for me as an amateur, I’m worthless as a builder and can’t do sculpties, but meshes, well, with such an incredible amount of tools out there, even I can use them 🙂

    It’s such a pity that I won’t be able to use most of them on my parcels, though…

  • I do agree. Well, in the mean time, we will get lovely avatars, wonderful clothing that allows us to sit properly on things and possibly amazing vehicles 🙂

  • Now that’s interesting! I thought that the a simple prim cube would just have the regular 12 triangles! Hmm. I’m pretty sure this was the case not so long ago!

  • Well, I have to agree with you, @a31e3bfbd0c720a61b3f434715c8d1f4:disqus — a combination of prims, sculpties, and meshes might be the best we get in the near future, and that’s nothing “wrong” with that! Also, as I’m sure I said somewhere, the issue is not a problem for professional 3D modellers, specially the ones working for the gaming industry — and we have tons of those in SL! They’re used to get, say, an original design for an item or avatar for a 3D game with a few hundred thousand triangles, and with adequate tools and a lot of work, reduce that to a more reasonable size — I understand that WoW, for example, has 2500-triangle-avatars — by clever use of textures and special shaders (which we don’t have in SL — yet! — but the end-result can be approximated). So, yes, good 3D professionals will be able to deal with the way PEs are calculated and adapt their content accordingly and still give us good results.

    For amateurs and artists, who are not used to deal with all the fuss of mesh simplification, it’s another story. As said, meshes can be easily created with, say, Photoshop and/or SketchUp, which are tools that even I can use — and certainly get much better results than working with prims (which I have absolutely no talent with). But naturally the results will be “unoptimized” meshes — and those will have a huge PE penalty. Now I’m not saying that LL is to blame! I remember that the first (and only!) house I built had about 100 prims, and it was little else but a cube with some windows and a sliding door. When I noticed that my parcel limit was just 117 prims, I was baffled — this was an ugly-looking, very simple house, and now I didn’t even have any prims left for my furniture! But was LL to blame for that? No. Any good content creator would probably do the same house with a dozen prims and good textures; it’s just the hobbyists and amateurs that don’t understand how you can build so efficiently. Pros are not encumbered that way.

    So, sure, you can easily build a house with SketchUp, and even add a lot of detail — but the resulting mesh might be severely encumbered with a high PE “score”. While pros who use Maya/3ds/Blender will just laugh at those crude meshes and be able to save so many triangles that the resulting mesh is tiny — and thus uploads with a very low PE score, no matter how weird LL’s calculations are. Those are the meshes that will eventually be able to compete in SL’s very tough and competitive marketplace.

  • Aliasi Stonebender

    Well, that’s the point of level of detail and size – small objects, from far enough away, won’t even be rendered – they’ll be occluded out for most people. The PE calculation discourages you from making the 500-foot Mesh Object That Ate Michigan without keeping the model far simpler. I won’t deny they could probably tweak the calculations, but mesh has one big hassle neither sculpties nor prims have. Prims are mathmatically described; all that has to be sent is a list of parameters the viewer interprets. Sculpties are always thus-and-so many polygons and can always be described as a deformed sphere; all you have to download is the sculpt map texture.

    Meshes can have a wholly arbitrary size and complexity (up to the limits of the format) which makes them massively more expensive; it’s why SL didn’t use this tech when it started out. The variation between a plain cube and a tortured torus prim is still small enough (on the backend) that it can be all abstracted to “one prim”.

  • Perhaps not.  LL has shot their other foot as well, because currently mesh clothing can only take skeletal shape parameters (e.g. height, leg length) into account, so that they don’t fully adapt to your shape–Procrustes would be proud! Worse yet, a JIRA proposal that would fix this and which has gotten a LOT of support from clothiers and other residents was recently moved from “sprint 28” to “maybe/someday”, so who knows whether anything will ever be done about it!

  • Darkbooty

    This needs to be brought to someones attention in Linden Labs. A shot in the foot to LL and a slap in the face to SL’s builders. This impairs optimization of sim builds simply because the prim scores get too high to use them. On the other hand this broken formula allows potentially many high detailed props to be placed in tiny scale which will undoubtedly become a visual strain on player hardware.

    As usual though functional problems like this get placed on the backburner since the margin of building players is so dwarfed by those who do not.