Why Prims are better than Mesh // OpenSimulator
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- Опубликовано: 16 окт 2024
- #OpenSimulator #OpenSim #XayTomsen
The rarely discussed bedrock of Open Simulator virtual worlds, I reckon it's time that we gave prims their deserved attention.
This topic will probably generate some outrage and arguments, and that's fine. Come at me baby coz I truly believe that prims rule and mesh sucks big time. :)
I'll have more Open Simulator videos and a couple of tutorials coming out shortly.
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And you can always download your buildings and use them in Blender. Easier then building them in Blender and importing them into Second Life or Opensim
I love building with prims, and it always impresses me what I can make with just the basic tools and understanding. I didn't even know that was why my viewer was so laggy when I would go exploring! This explains so much!
I'm glad you found the info helpful. Happy building!
Why doesn’t Second Life and Opensim use technology that Unreal Engine uses? Turn objects into pixels like Unreal 5
I'm no expert, but one thing I did pick up from the early discussions in the Ruth & Roth 2.0 project is that most of the mesh in both Second Life and Opensim isn't optimised and places a massive load on available resources. As a result both those mesh avatars have been optimised to load quickly, and certainly much faster than the many pirated SL mesh avatars widely available throughout the Opensim metaverse.
However, even here avatars are not implemented in the most efficient manner as they follow the 'traditional' SL model of being like a doll you dress rather than a fully dressed avatar created as such - why have detail that can't be seen, and indeed, needs a masking layer to hide elements of the avatar body that inconveniently show through, thus adding yet more server load. This is a valid consideration, but for most it seems that fitmesh avatars that can be clothed offer the most in terms of personal expression and flexibility. Server overload seems to be much less of an issue in Opensim than it is in SL, where mesh optimisation should be a far more pressing issue than it appears to be - go to a venue jam packed with mesh avatars wearing complex mesh outfits and not only does it take a age to load, but movement is likely to be like walking through treacle. On my Linux system it's even more serious due to a viewer issue where quite quickly all system RAM is soon maxed out and the system freezes. From what I've read this 'bug' only affects systems with more than two CPU cores. Whatever, it's been around for some years now and has effectively made places with excessive resource demand, i.e. those locations packed with badly optimised mesh, no-go areas.
On the whole though the mesh v prims argument is somewhat overblown. Both have their place, and in my view should only be used where they are the most efficient means of achieving a desired effect. To a large extent server resources aren't much of an issue for me as I host my own simulators, and mostly build with prims, which, for the vast majority of buildings are more than up to the job. Vehicles are a different matter, and it's here, as with avatars that I feel mesh offers more than the system defaults. Certainly here there is scope for mix & match: a prim box seems far more efficient than a mesh equivalent, but in terms of fine detailing, mesh wins hands down.
Yes, there are issues with loading times, but that's as much down to SL/Opensim being somewhat constrained by it being ancient code held back by a need for backwards compatability, (look at the whole 'baked-on' mesh craze, implemented at least partially to appease those wanting to wear that awful system outfit, complete with bling, that they bought in 2007) which is holding things back. In terms of viewer development, not only is the issue of of maintained compatability between SL and Opensim problematic, it also I think holds both projects back. That the viewer works on a version of OpenGL that hasn't been touched since 2006 is also going to be a factor holding both projects back - as a result my GTS 1060 GPU might allow me to max out draw distance and use Advance Lighting with all the bells and whistles at the same time, but the true performance of the graphics card is being strangled by ancient OpenGL code used in SL/OS.
Were the issues above solved and SL/OS, (preferably as separate projects) then most of the issues surrounding mesh load times could be solved. And whilst there is nothing like the constraints on prim usage in Opensim compared to SL, the SL rule of using as few prims as possible remains good, though often means a lack of detailing, which is where properly optimised mesh components come in.
Thanks for the comprehensive input Padi. Lots of good points and food for thought there.
@@andrewt2020com It's a great idea that creativity can be achieved through the viewer, though that does have the downside that anything complex and detailed is going to use a massive number of prims and as such becomes a non-starter for SL in practical terms. I haven't built anything in SL for a decade, but have built a couple of things that amount to over 1000 linked prims, including a car ferry that sails very nicely using a Kayaker script, and will even cross region boundaries on my experimental 4x2560x2560 sailing sim,(yeah, that 400 SL 'sims'). Both of those technically impossible in SL, and even if it was, I shudder to think what that would cost in terms of money!
My self-hosted region isn't currently running well, (I strongly suspect database issues) but an impression can be had from the website, which is badly in need of an update) ynysparadwys.weebly.com/
Lots and lots of prims, probably over 150,000 on a 1024x1024 varregion - and quite a bit of mesh too.
But why does my fully up2date avatar with everything mesh/bento/bom and layer upon layer textures only require between 20-50k complexity and is that flexi prim hair/skirt wearing bling avi between 150-350k and up? (Try it, turn complexity on in FS)
Same with houses, countless examples where that mesh house of the certain size with more details and more functions has a lower impact than a prim house of that same size.
Isn't it mostly about scripts and cpu ticks/time?
Thanks for your feedback.
If you're talking about land impact, sure, imported mesh is usually lower, which I conceded in the video, but land impact doesn't translate to how fast an object downloads to the viewer. I agree that flexi and scripted bling does take longer to appear than normal prims but the difference is only marginal, a couple of seconds at most. My main avatar's "royal" prim outfit includes 25 or so HUDs and flexi body attachments with approx 600 scripts and generally sits at around 35 to 60k complexity. Most of that is my hair which is 280 prims, about half of which are flexi. All of that only takes about 7 or 8 seconds to download from an empty cache.
The issue I'm getting at in this video is how long it takes for the viewer to show imported mesh. We've all teleported to a party or bar for the first time that is populated with mesh avatars that take several minutes to download. The same goes for the sample region I used in this video. After 20 minutes, all of that mesh still hadn't downloaded. It just aint pretty. If you're the only person using the region and no one ever visits or if you're not taking long distance photos where object deformity would otherwise be an issue, sure, land impact can be the main priority. If you have guests coming though, it's probably best to consider their experience as well. Responsibly textured prim objects always download faster than mesh from an empty viewer cache and I'm yet to see a single exception, but that's just my take on it.
I thought the prims are heavier to load (system wise) than the mesh objects. Apparently not. Guess it would be laggier with bakes on mesh where avis can wear layers upon layers of mesh.
I'm not sure what takes place at system level but replicating the same system mesh over and over would have to take less time than loading hundreds of custom meshes. This is reflected at viewer level at least, and that's where people decide to leave a region or stay. Where things go wrong with prims is when people decide to use crazy huge textures on small objects, which is a whole topic for another video :)
The LOD deformation is actually just- the fault of the creator. If you spend a bit of extra time in blender you can optimize LODs to the point that they’re invisible, but- that takes a fairly specialized skill and it’s not always easy or practical to pull off. On SL… a lot creators are fairly underpaid, so most of them don’t invest the time into it.
I am… one of these creators… ahahaha
Actually- Now I think about it… one potential reason why prims fell out of favor may be by no fault of their own as texturing software went on without it, and there’s no way to export prim creations from second life to another program.
Prims can easily accept any texture, but it’s slightly harder to make a texture that’s designed specifically to fit one particular prim in exactly the way that you want- and a major advantage of mesh is that you can easily import it directly into texturing software to paint right on the object or see your texturing updated in real time like you could in blender, substance designer, or substance designer unless you can make a mock up of it. For a cube- that’s easy, but as you alter the shape of the prim and increase the geometric detail it becomes less and less practical to try and make a mock-up for texturing and more practical to just… slap whatever texture you have onto there without making a special texture just for that one prim- which makes it overall less detailed. Which is probably why you don’t see many prims that use material maps to increase their illusion of visual complexity the way that meshes are able to.
I might, maybe, possibly… spend too much time in my art software…
I want to mention though- I do use prims! Whenever I have a flat featureless surface I switch from mesh to prim cubes, since those are easy to make mock ups of and the texture doesn’t need to conform to anything. It just needs to be an ordinary square image with no UVs to worry about.
Interesting topic.
I think prim builds generally look bland and featureless, dare I say noobish. I can tell a prim build instantly. It is not impossible to make a good looking builds with prims, but it will take a lot of them to add the fine details. I mastered building with prims many years ago and I refused to build mesh objects because I was so comfortable with how prims work. A prim whore if you will.
Sadly there are many organic shapes that you just can't convincingly reproduce with prims. Sculpties are not the answer either.
I have since learned Blender and how to make proper LOD's for meshes.
Performance issues occur when people cram thousands of poorly optimized high poly meshes into their regions. If you are careful when creating your meshes and don't go nuts with the polygons you can have a full city running smooth as butter.
The main thing I notice with freebie mesh objects found in all the freebie malls is that they are very high poly and don't have all the LOD's set up. So as soon as you move away from the object it crumples up into a mess, or even worse they force the high poly mesh to render fully at all distances.
A lot of people download a high poly model meant for rendering in Blender and upload it without making LOD's or reducing the polygons at all. If people would spend a bit of time making a mesh that is set up properly for a game, it will load quickly and be much easier to render than a high detail prim build.
With prim builds there are a lot of faces hidden inside other prims that don't need to be rendered, but still are because you cant remove them. Sure you can make some faces transparent, but the geometry is still there. With a well made mesh there are no wasted polygons hidden inside wasting resources.
Avoid sculpted objects like the plague.
At the end of the day I would rather take a properly made mesh building over a several thousand prim building of equivalent detail.
I think my main complaint is that people abuse mesh and don't use it properly.
Interesting..
Glad you think so!
at the end of the day, meshes are better optimized. having to render hundreds of separate object files as opposed to a single one is always going to be more expensive compute wise. sl lacks the tools to optimize prim building to make it superior to mesh building. and if the mesh is too expensive for the gpu to render, how tf would it cope rendering all those prims alternatively? all that work for something that looks half as good as a mesh, not a winner imo. a mesh is truly a single object, and a prim object is multiple combined objects. too many x and y positions being moved.
Of course though, poorly optimized mesh with high tri count ruin it for everyone. That's the only reason why the game lags, because of bad optimization, but if executed correctly, meshes are better option