Prim Mesh Equivalence.... the cost of a mesh.

In a recent attempt to convey to those interested, Runitai Linden posted an explanation of how LL is trying to work out the cost of a mesh, or, in very simple terms, if you can rezz 15,000 prims on a sim, how many mesh will you be allowed??

As you read through it here you will find it is a fairly complicated calculation... but this paragraph stuck in my head...

“Given that Second Life has bad framerates and prims aren't exactly stingy about wasting triangles, it's wise to bias meshes towards the low end of that spectrum, say at 250 thousand triangles give or take 50 thousand.  THAT is your visible triangle budget.  In order for Second Life to have a prayer of running well in a mesh build, the meshes MUST display no more than that number of triangles per frame.’

Now, just how much, or rather, how little 250,000 triangles is.... consider the following post by  Dain Shan where he calculates that 15,000 prims have 1,800,000 triangles. However.... not all of those are visible at one time...

By definition you would be able to see either 2 or 3 faces, so... that’s a third or a half... 600,000 or 900,000....

...but “ In order for Second Life to have a prayer of running well in a mesh build,” LL will make sure that the allowance is well within that 200,000 to 300,000 ‘budget’.

“ it's wise to bias meshes towards the low end of that spectrum”.. but for who? Yes we are agreed with LL that lag is bad... but... if I have been told once, I have been told 30 times that Mesh is gonna reduce lag.

Well, if the number of meshes per sim is reduced to a low enough level that will of course become a self-fulfilling prophesy.

In a later post, Drongle McMahon writes the following...

“3. (/me restrains himself) While discussion of meshes in isolation is very useful, it is my opinion that it is dangerous to ignore comparison with sculpties. The latter will be used instead of meshes if they are allowed, especially at 64m, without further restrictions. This is a very real problem for the uptake of mesh that threatens the resource efficiency and visual quality improvements that are otherwise offered. I will not say more, as requested.

PS. I guess the requested resp[onse tom the sculpty comparison is that a sim full of sculpties will not reach the performance required. So if people do fill up their sims with sculpties, that is their problem. We can't stop sculpties messing thins up, but we can stop meshes doing the same. That way people will eventually reject the sculpties?”

Now....before we get totally lost in the detail....

It seems to me, from these discussions, that I am getting more sculptie triangle for my Linden buck than I have any chance of getting using mesh.... and the idea is that it will be a positive thing if people reject sculpties and go for mesh.

This is surely not because LL will make more money from mesh uploads......

Is it because upgrading the servers or the server capacity would cost LL money and the same effect could be achieved by reducing the current 15,000 prims per sim in a poor exchange rate with mesh.? ...(poor for me, good for LL).

“So if people do fill up their sims with sculpties, that is their problem. We can't stop sculpties messing thins up, but we can stop meshes doing the same. That way people will eventually reject the sculpties?”

Now, I understand if Drongle is being misunderstood here, but it seems to me that putting 15,000 sculpties on my sim for $295 is a part of the deal, not me “messing things up”...??
The desire he has to convert us all to mesh because persistent use of sculpties.. “threatens the resource efficiency and visual quality improvements that are otherwise offered“ could surely be achieved by improved server functions.... anyway that’s tier.

So....to sum up... by restricting the number of meshes allowed on a sim “In order for Second Life to have a prayer of running well in a mesh build” LL will have less of a load on the servers than if I rezz 15,000 sculpties on my sim ... but... will I get a tier reduction if I convert to mesh? ...(smiles)...

In actual fact the uploading of mesh will be far more expensive than a sculptie. That is a prediction, not fact, but... logic dictates that when I upload a mesh, I am in fact uploading data on 3 different LOD (“level of detail”) and, for clothes, the rigging data too (how the clothes fit on the “skeleton”), that seems like a lot more data than a 64x64 pixel sculptie map...
..as this is pure speculation we will have to wait and see.

But, the question still remains, in my mind, who will benefit most from mesh?



Now the ecstatic fangirls are still spouting nonsense about Mesh, still oblivious to the fact that mesh can't be sized or flexible so the likelihood of it being used for clothes or hair is remote...2013/2014? and the most condescending of these posts from Gwyneth Llewelyn, but maybe I just misread the tone of the article... I apologise if I have in advance.

Anyway I just wanted to assure anyone who is in any doubt that my scepticism towards mesh is not due to the fact that I don't have a degree in Computer Science, or that I couldn't use Maya (if I had 3000$ to spend on software), I am happy to upload my Blender files as Collada instead of .tga. My scepticism comes from the past performance of LL when 'upgrading' the User Experience, the word Upgrading translates too often as Breaking.

I welcome any real improvement to the platform, but Runitai Linden knows, as we all do, that the first release will be buggy. After 18 months the V2 is apparently nearly usable, and by 2014 mesh may be a great feature... but fangirl hysteria (not a hypothetical techno fear) just inspires me to cynicism.

Meshy Christmas will more likely be a Messy Christmas.


:))