Jump to content

How to make efficient mesh - general principles


ChinRey
 Share

You are about to reply to a thread that has been inactive for 664 days.

Please take a moment to consider if this thread is worth bumping.

Recommended Posts

There are a lot of tricks and techniques to make the most out of the limited rendering resources we have in a virtual world. I'm working on documenting them all but it'll take a while since it's a huge task and I can only work on it on the rare occasions when I happen to have a few minutes to spare.

However,  the BIG secret is not in all those details, it's about understanding how it works. So here are a few general principles. If you regard yourself as a skilled SL builder, you should know all of this. If you're a happy hobbyist, well not everybody are supposed to be experts of course but the more you know, the better you will build.

  1. Rule no. 1 is: It is impossible to create a virtual world!!!
    • What?
    • It's true. There will always be limits to how much power a computer will have but there are no limits to how much details we need for a genuine virtual reality. Fortunately we have a work-around for it. It's what's technically known as cheating.
    • We don't really need to make a genuine virtual world. We only need something that the human eye perceives as one and the human eye is easily fooled.
    • It's so tempting to try too hard to cram every little detail into our model but that doesn't work. Too many details can actually reduce the overall effect since they can distract from what we really want to highlight and distraction is the enemy of experience. So:
  2. True art is never about what you can add to your work but what you can leave out!
    • Knowing what to throw away and knowing what to keep, that's the trick. Keep that in mind and everything here will make sense, forget it and it won't.
  3. Use your eyes!
    • It's so easy to forget.
  4. Beware of builder's blindness!
    • This is a special case of #3 but important enough to be mentioned separately. When we do creative work, we enter a zone where we get "tunnel vision", focusing entirely on whatever we're working on. That's all well and good, it's exactly how it should be. But once all the fiddly detail work is done, we need to snap out of it, look up and see our work as it fits in a bigger picture.
  5. Wait a day!
    • And then look at what you made again with fresh. It's amazing how many things that were important yesterday suddenly aren't and how many things that weren't suddenly are.
  6. Content may be King but without Queen Context he is nothing at all!
    • We do not build standalone models for a virtual world, we build parts for a bigger picture. Even if that part happens to be the main focus point of the scene (it almost certainly isn't), it still has to fit in with the surroundings.
  7. Are you building for yourself only or for others too?
    • This is an important point to consider. If it's something that is for your own private island where nobody else will see it, you optimize for the load level your computer can handle. If it's for others too, you have to remember that not all people have access to computers and internet connections as string as yours.
  8. Don't do Mesh for Mesh' Sake!
    • Prims are fundamentally far more suitable for online real time rendering than mesh. So:
      • If your model can be made from a single prim, make it from a single prim.
      • If the land impact (calculated the modern Second Life way) is higher for a mesh with proper LoD than for a linkset of prims, make it with prims
    • There are of course no rules without exceptions, but in  this case the exceptions are very few.
  9. Know the LoD swap distances!
    • You can do the math or you can do test uploads and use your eyes. But do not forget this step! There is no way you can optimize without actually knowing what to aim for.
  10. Do not optimize for a high LoD factor!
    • The LoD system, for all it's flaws and as annoying as it can be sometimes, is one of the crucial mechanisms that makes a virtual world possible at all. If every single tri and vertice of every single object in a complex scene was to be rendered, even the strongest GPU in the world would faint.
    • But disabling the LoD system is exactly what people try to do when they crank up their viewer's LoD factor. It's not possible to completely disable it this way of course but even so, building for high LoD factors means fewer people will be able to see what you made. The moment you get to the point where you need a game computer, not a regular home computer to render the scene efficiently, you've lost most of your potential audience. Do you really want that?
    • The default LoD factor for the standard Second Life viewer is 1.25. Firestorm, the de facto standard on opensim, is a bit more "generous" with a default of 2.0. Even so, some computers struggle to handle the defaults and even with a strong game computer, you may have to sacrifice scene complexity and/or draw distance to compensate for an inflated LoD factor.
    • You have to optimize for a specific LoD factor, that can't be avoided, but the question is which. My advice is to test with LoD factor 1.0, the original default but don't expect absolutely flawless visuals with that. The aim is:
      • LoD factor 0: Forget about it. 0 means only the lowest LoD model is ever used and if we strengthen all LoD models that much, we are actually disabling the LoD system completely.
      • LoD factor 0.5: Try to get a descent look even at this low value. But if it isn't possible, it isn't possible.
      • LoD factor 1.25: Ideally rock solid LoD but some flaws are acceptable. No collapsed LoD model messes though and no objects suddenly vanishing before its size is so small it doesn't matter.
      • LoD factor 2.0: Very small objects may be visibly distorted but still identifiable when viewed from a long distance. Apart from that, only minor, barely noticeable, LoD distortions.
  11. Do not over-strengthen the LoD models!
    • Remember there is a reason we have the LoD system in the first place. Over-strengthened LoD models have much the same negative effect as inflated LoD factors, they add excessive data to download and force the GPU to do a lot of unnecessary work. There seem to be three different reasons why some content creators don't reduce their LoD models enough:
      • Automatically generated LoD models
        • Whether it's part of the modelling software, like Blender's decimate modifier and limited dissolve or the uploader's LoD generator, an algorithm does not know how your model looks and it does not know which details are needed for each LoD level. They will always remove details that should have been kept or keep details that should have been removed or, as often as not, both. Such algorithms can be very useful for making LoD models but they can only give you a starting point, you have to check and correct the mistakes manually afterwards.
      • Lack of skills/care
        • Sadly many of the best designers in Second Life and on opensim are guilty of this mistake. They don't know how to make proper LoD models or they don't care and rather than going for collapsed LoD, they over-strengthen. To be fair, at least they are erring on the right side. LoD butchery is far worse than over-strengthened LoD.
      • Mole mesh
        • Named after the Moles, a group of amateur content creators doing contract work for Linden Lab. The reason they make so poor LoD models is probably partly because of the two factors above, dependence on automatic LoD and lack of skills. But Patch Linden, the head of the Moles, has indicated that there is a third reason too and it's a rather sad one. The idea is that some users have to reduce their LoD factor below the default because their computers aren't strong enough to handle all the tris. So to give those people the best possible experience, the Moles make the LoD models so strong the user can still see the model in it's full glory ... with all those tris their computers can't handle. Logic doesn't get fuzzier than this and as the old saying goes, the road to Hell is paved with good intentions.
  12. Do not use LoD models generated by the uploader!
    • See explanation above. Even the most inexperienced mesh maker is much better at judging which details are needed and which aren't than any computer algorithm can possibly be.
  13. Do not use "zero LoD" models generated by the uploader!
    • A zero LoD model is a throw away one that is just reduced to as few tris as possible with no regard for its looks. The idea is that if you can't make the lowest and even the low LoD model good enough to be acceptable, the best solution is to try to make the object go away at those view distances. Zero LoD models are not generally a good idea in any case but if you want to use them, make them properly. What you need are two tiny triangles defining the size of the bounding box - a few more if the mesh has more than two faces. It only takes seconds to make and it's so much better - or less bad - than the very visible mess the uploader tends to create.
  14. Remember, the High LoD model is a LoD model too!
    • All the simplification techniques and principles apply to the high LoD model as well as the others. Sometimes it's a good idea to keep a separate full details model that is only used as a basis and never uploaded.
  15. The High LoD model is not usually the main LoD model!
    • This is a surprise to most and very important to keep in mind.
    • LoD swap distances depend on object size and LoD factor but with the default camera position and object as big as 1x1x1 m in size right at the avatar's feet is rendered as mid LoD. With the LoD factor set to 2 a 0.5x0.5x0.5 m object at the avatar's feet is rendered at mid LoD. In other words, medium sized objects near the avatar are usually rendered at mid LoD, small objects usually at low or even lowest LoD!
    • This is not a bug or a flaw, at least it didn't start off that way. It's a feature and a potentially great one too if content creators could only take advantage of it. Complex objects have lots of details you want to show up when people take a closer look at your great work but you don't want to clutter up the scene. By placing a LoD swap point between the closeup and casual view distances, you can make the high LoD model almost as complex as you like and still keep the item nice and low lag.
  16. Take everything you know and learn about mesh optimization for mesh in general and for game mesh with a grain of salt!
    • It's easy to think we're the center of the (virtual) world but 3D modelling is such a huge and varied field. We have computer assisted design (CAD), 3D printing, static models for static photos, movie sets that are rendered frame by frame etc.,etc., etc.
    • Modelling for real-time dynamic rendering is only a tiny little bit of it all, completely dwarfed by the big 3D modelling fields. And it has some very special requirements when it comes to performance so a lot of what you can learn about 3D modelling in general simply don't apply here.
    • And dynamic rendering is mostly about games. Games use much simpler graphics than virtual worlds, they don't need nearly as much content to be downloaded on the fly and they are based on completely different software. So most of what you learn about game assets don't apply to virtual worlds either.
  17. There is no software for making virtual world style mesh!
    • Surprised?
    • It's true though. As mentioned above, 3D modelling is a big and varied field and the software is made for the big market with no regard for the tiny niche called virtual worlds. Big programs like Blender, Maya, ZBrush and 3ds Max do have all the features we need - often as add-ons created by Second Life and opensim users - but they tend to be stowed away in some hidden corner, out for sight for the regular 3D modellers who have no use for them.
  18. Work in Edit mode, not Object mode!
    • This applies to Blender and Maya and probably other modelling programs as well. There is no way you can make efficient meshes for virtual worlds without handling the vertices and polys directly.
  19. Work with quads and well defined edge loops and edge rows as much as possible
    • This isn't really a rule for optimizing mesh as such but how to do it efficiently. A messy mesh is sooo hard to work with so spend a few minutes cleaning it up before you start and keep keep it as clean as possible throughout the process. It'll save you a lot of time in the end.
  20. Consider realistic max draw distance!
    • But be careful!
    • For an outdoors object you want it to look decent all the way to max. draw distances and beyond or at least to the point where you are certain it's too small to be seen even on the biggest screen.
    • For an indoors object you may cheat a little bit. But remember that rooms in SL and opensim houses can be very big and houses have windows too.
  21. Consider realistic view angles!
    • Will the object ever be seen from below? Or from high above? or from behind?
    • You can save a couple of tris by taking this into account but again: be careful!
  22. Reuse assets whenever possible!
    • Second Life and opensim don't have object instancing as such but we can still save a lot by reusing meshes and textures. (Since I was a bit rude to the Moles earlier, I should give them due credit too: This is something they are really good at.)
  23. Do not mix large and small tris in a single mesh!
    • LoD swap distances are determined by the overall size of the object, download weight, render cost and land impact by the number of tris. By combining small and big tris you get the worst of both worlds with lots of tris that are kept at distances far beyond where they should have been eliminated.
    • This is not an absolute rule and there are a lot of exceptions to it. But you really need to know what you're doing to mix big and small safely so it's only for the advanced mesh maker.
  24. Split your mesh intelligently!
    • We do not want to squeeze too much into a single big mesh for a number of reasons. We split meshes to separate parts that need different LoD handling, to reuse identical parts, to balance the load between various part of the loading/rendering pipelines, to control the land impact etc. How to split a mesh effectively is an art in itself but there are some general rules and factors to consider:
      • Tris that belong to different faces/materials can be split with no actual load increase.
      • At the moment splitting tris from the same material/face will increase the actual render cost a little bit since it adds more draw calls. It's usually not much though and besides, at least two teams are working on Vulkan based viewers as I write this. Vulkan doesn't use draw calls the traditional way so once those viewers are launched, it won't be an issue anymore.
      • Splitting can increase or reduce load time. Each split increases the overhead but it also makes easier to handle for the computer. It's a tricky balance.
      • Due to a strange quirk in Second Life's land impact algorithm splitting tends to reduce the total download weight but it does increase the server weight. Since both of these weights can count towards the land impact, we can often reduce the LI by balancing the two.
      • Opensim has a different quirk: splitting will always increase the land impact even when it actually improves the performance.
  25. If you use the same model for two or more LoD levels, use the "Use LoD above" menu option!
    • If you do it by selecting the same model twice, the computers won't know they are identical so they have to be downloaded separately and the render engine will waste time switching between them.
    • Unfortunately of the many flaws in the way download weight and land impact is calculated in Second Life (not opensim) is that it doesn't take the performance gain from the "Use LoD above" option into account. Linden Lab does recognize this as a bug but they don't seem to be in a hurry to fix it.
  26. If you can only save a few tris from one LoD level to the next, don't bother, use the same model for both!
    • Switching between models is work for the viewer too and each LoD model has to be downloaded separately. So if there is only a slight difference, you will loose more than you gain. The general rule of thumb is that if you can only reduce the tri count by less than 25%, don't do it - use the same model for both levels. This is only a rough guideline though and there are also two important exceptions and one tempting cheat:
      • It can be worth accepting a lower reduction rate if it means you can use the "LoD above" option further down the hierarchy. For example, let's say the high model has 100 tris and the mid and low models both need 80. That's only a 20% reduction but it's still worth it because it affects two LoD models, not only one.
      • Each face of a multiface mesh is actually treated as a separate object (called a "submesh") by the render engine. This means that ideally we want to consider the reduction rate for each face individually rather than for the mesh as a whole.
      • The cheat only applies to Second Life, not to opensim: Due to the "Use LoD above" bug even an insignificant reduction of tris from one LoD level to the next will lower the calculated download weight and sometimes the land impact. We don't recommend cheats here of course but this one is rather tempting if it's enough to reduce the LI a point and it's certainly a less destructive way than many of the other techniques less skilled mesh makers use to reduce LI.
  27. Try to make the switches between LoD models as smooth as possible!
    • Mind you, I said try. We can't always achieve flawless LoD swaps without spending an excessive amount of resources on them but we have to be aware of the issue and do our best to minimize it.
  28. Play with your normals!
    • Even a beginner need to know how to use smooth normals to smoothen curved surfaces. As for the advanced builder, there is  just sooo much we can do with them!
  29. Do not try to save on geometry by adding textures and/or normal maps!
    • This is not an absolute rule but when it comes to performance, adding a custom texture or normal map to save a handful of tris is counter productive. Usually you need to be able to get rid of hundreds, even thousands, of tris to justify adding a single extra texture.
    • Unfortunately Second Life's land impact algorithm doesn't know this. It penalizes extra tris heavily and completely ignores texture pixels.
  30. Remove all hidden tris!
    • This should be unnecessary to say but unfortunately it isn't.
    • A good tip is to eliminate the hidden tris as late as possible in the modelling process and keep a master copy with them all in place. The reason is that once you break the pattern of the object's geometry, it becomes much harder to edit.
  31. Don't bother with single digit tri counts!
    • Well, you can if you want to of course or if that happens to be what works best. But once you get a LoD model down to about 10-15 tris, there's hardly anything to gain by taking it further.
    • (Personal note: One of my pet peeves are vendor boards, signs and other flat cubes that collapse into a single tris at a distance. Why, why, WHY??? Never mind such objects are usually better made with prims anyway, by doing it this you not only ruin the visual appearance of the object, you actually increase the load a little bit compared to using the "Use LoD above" option. Whoever make such monstrosities has no understanding whatsoever of even the most basic principles of mesh making.)
  32. Be flexible
    • Yes, you know exactly how you work will look before you even begin building. But don't be afraid to adjust your plan as you go along. If it ends up exactly the way you envisioned it, you've probably done something wrong.
  33. Budget luxury first
    • A big and often forgotten secret. A good rule for master chefs is to never mix expensive ingredients. Not only do they cost too much, they also tend to interfere with each other. It's the same for 3D modelling.
  34. Kill your darlings!
    • Those little but oh so expensive details you just have to have, are they really, really worth it? Consider it carefully, maybe you should get rid of them? Yes, it hurts but it's for your own good.
  35. Look for opportunities!
    • Are there any cool little details you can add at very little extra cost? Go for it! And of course, the opposite too: Are there any details that cost more than they're worth? Better leave them out then.
  36. Work with your raw materials!
    • Second to last but not least. I once heard an old wood sculptor explain it very well. He said he wasn't trying to make a shape out of the piece of wood he was working on, he was trying to bring out the shape that was hiding inside it. This is the essence of all true art and all true craftsmanship and it brings us nicely to the final point that shouldn't need any explanation:
  37. Do the possible and you'll achieve the impossible!
Edited by ChinRey
Typos
  • Like 3
  • Thanks 11
Link to comment
Share on other sites

18 hours ago, ChinRey said:

The idea is that some users have to reduce their LoD factor below the default because their computers aren't strong enough to handle all the tris. So to give those people the best possible experience, the Moles make the LoD models so strong the user can still see the model in it's full glory ... with all those tris their computers can't handle.

😠

Link to comment
Share on other sites

It's frustrating that you are here basically making a giant listicle that says "Be better with your LODs @ creators" - But the reality is that modern computers (not the bull junk from years ago.. if you are using a computer that was made before 2014.. what are you even doing on a game like Second Life) can very much handle the tris - the GPU VRAM is being overloaded by textures in the pursuit of crisp detail in Second Life. People walk around with outfits that the mesh may be (somewhat) optimized, but then they will have 4 1024 textures on a single pair of pants. (And dont get me started on people who put all of their textures on a prim inside the pants so that when they use the HUD it "loads faster"... but makes everyone around them load 50+ 1024's while they are wearing a simple pair of jeans) 
There's also no talk whatsoever on symmetrical workflow (which is probably the FIRST question everyone should ask themselves whenever they are making game assets for anything)

You really could've just condensed this to "Make custom LODs and clean up your tri count" (which tri count, again, is becoming less and less important to worry about)

I'm not saying tri counts dont matter, but I am saying texture count > tri count when it comes to optimization.

  • Like 2
  • Haha 2
Link to comment
Share on other sites

3 hours ago, Dom Daddy said:

I'm not saying tri counts dont matter, but I am saying texture count > tri count when it comes to optimization.

Oh yes, texture optimisation is much more important than poly/vertice optimisation when it comes to performance and that is why I coverd it first. It's more than a year since I posted my "Deadly Sins of Texturing" though, so here's a link to them.

I wish I could write this builders' manual in one go but it's unpaid work and apart from the occasional likes in the forums there's nothing really in it for me. So I have to just add a little bit at a time whenever I happen to have a bit of time to spare.

  Edit:

3 hours ago, Dom Daddy said:

You really could've just condensed this to "Make custom LODs and clean up your tri count" (which tri count, again, is becoming less and less important to worry about)

We could also condense texture optimisation to "don't waste pixels" but that's not very helpful.

At this stage (I'm planning to add more practical tips later) this is all about getting content creators to think about optimisation at all. Second Life is full of excellent designers who made the most wonderful looking items but don't seem to recognise the performance aspect of good 3D modelling. There are also a lot of myths and false information leading builders astray. We could gain a lot if we could get all builders to think about it rationally.

Edited by ChinRey
  • Like 1
Link to comment
Share on other sites

On 7/6/2021 at 10:45 AM, Dom Daddy said:

(And dont get me started on people who put all of their textures on a prim inside the pants so that when they use the HUD it "loads faster"... but makes everyone around them load 50+ 1024's while they are wearing a simple pair of jeans)

Wow, good point, thank you!

I've added it to the list of Deadly Texturing sins. I hope you don't mind that I quoted you there.

Link to comment
Share on other sites

3 hours ago, Rya Nitely said:

Maybe I missed it but did you mention physics models? It has a significant impact on LI. I use a triangle for my plants, which are phantom so it doesn't need a physical shape.

 

2 hours ago, ChinRey said:

I'm afraid that'll have to wait; as I said, there are limits to how much time I can spend on this.

ChinRey's alter-ego posted a relevant response on the Kitely forums a while back (I may or may not have perved through her blogs and such a few days ago. . .)

https://www.kitely.com/forums/viewtopic.php?f=25&t=5691

  • Like 1
  • Thanks 2
Link to comment
Share on other sites

  • 10 months later...

@ChinRey All very good points, and if more creators followed them SL would be more efficient and less lag for everyone :D

Here's how the real experience is  with some observation:

1903368685_LODMeshCounts2022.thumb.png.5f08ef056856dc3bd4f3bcdb177de74c.png

[Redacted: Being observant is not so good for one's health it seems :D Shhhhhhh....]

Do they not notice that their objects are decimating or blinking out only 5m away when they do this?

[Redacted]

Rainn Wilson GIF - Rainn Wilson Shh GIFs

 

 

Edited by Codex Alpha
  • Like 1
Link to comment
Share on other sites

7 hours ago, Codex Alpha said:

Do they not notice that their objects are decimating or blinking out only 5m away when they do this?

My guess: they do, but they blame it (possibly in bad faith, possibly in full sincerity) on people having underpowered computers that can't handle real graphics settings.

  • Like 1
Link to comment
Share on other sites

On 7/1/2021 at 3:32 AM, ChinRey said:

Do not use "zero LoD" models generated by the uploader!

I'm making something and and LOD0 I think took me the longest.

 

I deleted every edge I could without breaking the general shape or UV maps.

I got to the point where I squished the LI of the object to 4.9 and no other edge could be destroyed without it breaking the mesh. So I removed all the side faces so on Lod0 it looks completely flat 

 

Never occurred to me I can just 'hide' the LOD0 with just a few triangles (I'd probably scale them to almost 0) and assigning the materials I have to said triangles.

 

Would it be OK to make Lod 0 seem like it's really no there like you mentioned?

 

I started meshing a few months ago, even if I sell the object noone will complain that it disappears when zoomed out all the way?

 

If I remove LOD0 it'll probably make the LI of the object even lower.

 

 

  • Like 1
Link to comment
Share on other sites

21 hours ago, arisaie said:

I'm making something and and LOD0 I think took me the longest.

I deleted every edge I could without breaking the general shape or UV maps.

I got to the point where I squished the LI of the object to 4.9 and no other edge could be destroyed without it breaking the mesh. So I removed all the side faces so on Lod0 it looks completely flat 

Depending on what it is, I often create the LOD0 from scratch. It will just be a few polygons anyway, so uv mapping those onto the texture is quick, and easy as well.
When reducing geometry doesn't work well, I also like to make LOD0 as an imposter model. Projecting the LOD3 model onto a cubic like shape. Baking diffuse, normal, spec to  maintain the shading. (these texture maps can be really small, like 128x128, 64x64. I usually put the diffuse and the normal onto a single 128x128 and adjust the texture offset and scale in-world accordingly)

21 hours ago, arisaie said:

Never occurred to me I can just 'hide' the LOD0 with just a few triangles (I'd probably scale them to almost 0) and assigning the materials I have to said triangles.

Would it be OK to make Lod 0 seem like it's really no there like you mentioned?

I started meshing a few months ago, even if I sell the object noone will complain that it disappears when zoomed out all the way?

Well, as I know ChinRey, I don't think that she is really recommending this. It's just trading something bad, for something that is a little less bad.

Looking at an object on it's own, it may not be that obvious what is happening. But when I think of that this is placed somewhere in-between other objects of similar size, and 1 object is dropping out of existence while everything else around it stays put..... 🤔

21 hours ago, arisaie said:

If I remove LOD0 it'll probably make the LI of the object even lower.

Maybe so, maybe not. Depends on the size of the object. But having something around 12 to 20 triangles in the lowest, won't do much harm regarding LI either.
 

Edited by arton Rotaru
  • Like 2
Link to comment
Share on other sites

2 hours ago, arton Rotaru said:

Depending on what it is, I often create the LOD0 from scratch. It will just be a few polygons anyway, so uv mapping those onto the texture is quick, and easy as well.
When reducing geometry doesn't work well, I also like to make LOD0 as an imposter model. Projecting the LOD3 model onto a cubic like shape. Baking diffuse, normal, spec to  maintain the shading. (these texture maps can be really small, like 128x128, 64x64. I usually put the diffuse and the normal onto a single 128x128 and adjust the texture offset and scale in-world accordingly)

Well, as I know ChinRey, I don't think that she is really recommending this. It's just trading something bad, for something that is a little less bad.

Looking at an object on it's own, it may not be that obvious what is happening. But when I think of that this is placed somewhere in-between other objects of similar size, and 1 object is dropping out of existence while everything else around it stays put..... 🤔

Maybe so, maybe not. Depends on the size of the object. But having something around 12 to 20 triangles in the lowest, won't do much harm regarding LI either.
 

I just realized this thread is from last year..oops!

Never thought about doing it from scratch.

 

I assumed the uploader won't accept it if the UV and the entire UV space and materials are not the same as on the highest model. So that's what I've been doing, removing edges, merging vertices but only to the moment where the UV looks the same (minus the dissolved edges and merged faces).

 

Or is just the materials need to be the same and the UV just roughly similar?

 

 

As for the impostor object. Do you have a link to a tutorial or something? I think that'd be really informative for the future.

 

Edited by arisaie
Link to comment
Share on other sites

1 hour ago, arisaie said:

Or is just the materials need to be the same and the UV just roughly similar?

It's just the materials that have to be present in all LODs. Except you upload mesh with a recent Firestorm viewer. Then only LOD3 requires all the materials. The lower LODs can have any subset of these materials present in LOD3.

1 hour ago, arisaie said:

As for the impostor object. Do you have a link to a tutorial or something? I think that'd be really informative for the future.

Unfortunately no, I don't have a link, or tutorial. I could put something together, but that would be in 3ds Max. The principle is quite simple though. You just build some planes around an object, and then project the textured model onto those planes. Similar of how a highpoly to lowpoly bake is being done.

  • Like 1
Link to comment
Share on other sites

On 5/22/2022 at 3:21 AM, arton Rotaru said:

It's just the materials that have to be present in all LODs. Except you upload mesh with a recent Firestorm viewer. Then only LOD3 requires all the materials. The lower LODs can have any subset of these materials present in LOD3.

Unfortunately no, I don't have a link, or tutorial. I could put something together, but that would be in 3ds Max. The principle is quite simple though. You just build some planes around an object, and then project the textured model onto those planes. Similar of how a highpoly to lowpoly bake is being done.

I was thinking how am I supposed to add another texture after reading through the post Quarrel mentioned, thinking that's not possible..

The I got it...Materials! 

I'm quite satisfied how it looks, even used the impostor on details on LOD1 to get rid of some more triangles. No moving faces, shape kept even on lowest LOD.

 

I have a couple of questions though if you don't mind.

 

1. If I use impostors, does the alpha settings need to be set to blending or masking? Won't I get alpha fighting if I theoretically use multiple impostors overlaying in the future? I know some alpha settings make clothes, body or hair transparent. How can I be sure it won't happen?

2. How can I lower the physics cost? My object is split into 4 (3LI Vs 14LI if uploaded as 1 object 8x4). I made the physics into 4 planes that are on top of my mesh as I have 4 objects. Currently the physics cost is 1.72.(uploader says 1.720 base hull, 2.5 mesh)

3. Is there nothing I can do to squish the server cost? It's 2.5 ATM. Is it high because I split the mesh?

Link to comment
Share on other sites

On 5/18/2022 at 5:56 PM, Codex Alpha said:

[Redacted: Being observant is not so good for one's health it seems :D Shhhhhhh....]

I know! ;)

 

On 5/18/2022 at 5:56 PM, Codex Alpha said:

Do they not notice that their objects are decimating or blinking out only 5m away when they do this?

I think it's much about builder's blindness. It's so easy to become so focused on how your build look in Blender or Maya you forget how it works in the context of a larger scene.

  • Like 1
Link to comment
Share on other sites

On 5/21/2022 at 1:51 AM, arisaie said:

I'm making something and and LOD0 I think took me the longest.

It's also often the most frustrating part since you want to keep everything but you can't!

 

On 5/21/2022 at 11:27 PM, arton Rotaru said:

Well, as I know ChinRey, I don't think that she is really recommending this.

You know me too well, Arton. ;)

But I don't reject it either even though I've never used it myself. Sometimes replacing something bad with something less bad is the only realistic option. Do not use the trick for big and/or prominent objects though. Trees and houses that pop in and out of existence, that's bad. Really, really bad even. Smaller items you can get away with but even so, always regard zeroing out an object as the last resort and if you do it, do it the way Arisaie suggests, with properly hidden tris, not by setting the triangle threshold to 0 in the uploader.

 

On 5/21/2022 at 11:27 PM, arton Rotaru said:

When reducing geometry doesn't work well, I also like to make LOD0 as an imposter model.

I don't like to use impostors for three reasons: It limits the options to retexture the object to fit different surroundings, it makes it harder to get smooth transitions between the LoD models and I'm too lazy.

Adding an extra texture for the impostor isn't really ideal either of course but as Arton points out, you can keep its resolution very low so it's usually not big deal.

And sometimes you don't need to add an extra texture at all. I mentioned this in the thread Quarrel linked to but I may not have made it clear enough so here's another even older example (I made this mesh 8 years ago! How time flies; I suppose I can't call myself a newbie anymore.)

image.png.3e0ab4829b5bd768eb45f214d3831d62.png

The deck of this pier is quite elaborate with uneven and slightly twisted planks:

image.png.b8fbeefc585a508cedadb0c471c4948e.pngimage.png.2a5dfc6a16d8dc56c8387f9db66cb9a9.png

But on the LoD models it's just a flat sheet and it still uses exactly the same texture (one of Nighty Goodspeed's lovely Weathered Wood ones):

image.png.0b22e51fc3224f60a886485badfba532.png

This pier was made completely with Mesh Studio btw. It dates back to before I had even started to use Blender. That's why the posts are just plain cylinders. Today I probably would ave added a bit more detail to those. But it's not really a big deal, they're mostly under water anyway.

  • Like 3
Link to comment
Share on other sites

5 hours ago, arisaie said:

1. If I use impostors, does the alpha settings need to be set to blending or masking?

Masking is always first choice, blending only if masking doesn't work. It shouldn't make much difference for an impostor though.

 

5 hours ago, arisaie said:

2. How can I lower the physics cost?

We need to know a bit more about your model to answer that. Can you post some pictures of it?

 

5 hours ago, arisaie said:

3. Is there nothing I can do to squish the server cost? It's 2.5 ATM. Is it high because I split the mesh?

Server cost is 0.5 for each part of the linkset plus 0.25 for each active script. So if you have split it into four and and end up with 2.5 server cost, it means you have two scripts running. Can you combine them into one?

  • Like 1
Link to comment
Share on other sites

1 hour ago, ChinRey said:

I don't like to use impostors for three reasons: It limits the options to retexture the object to fit different surroundings, it makes it harder to get smooth transitions between the LoD models and I'm too lazy.

Adding an extra texture for the impostor isn't really ideal either of course but as Arton points out, you can keep its resolution very low so it's usually not big deal.

Yeah right, I'm happy when I can avoid making impostors, too. Mainly because of the extra texture set that I usually have to add. Planning way ahead, and leaving some space on the regular UV map doesn't work for me somehow. I'm always to eager to fill the UV space to it's limits when unwrapping a model. 🤪

  • Like 2
Link to comment
Share on other sites

7 hours ago, arisaie said:

2. How can I lower the physics cost? My object is split into 4 (3LI Vs 14LI if uploaded as 1 object 8x4). I made the physics into 4 planes that are on top of my mesh as I have 4 objects. Currently the physics cost is 1.72.(uploader says 1.720 base hull, 2.5 mesh)

3. Is there nothing I can do to squish the server cost? It's 2.5 ATM. Is it high because I split the mesh?

C'mon.... how low you want to go? 😋 It's 3 LI already for a fairly large build it seems.

  • Like 1
Link to comment
Share on other sites

23 hours ago, arton Rotaru said:

C'mon.... how low you want to go? 😋 It's 3 LI already for a fairly large build it seems.

Yes sometimes everyone forgets that we had to build with prims, and so 3 Li was reached even if only 6 blocks.. Now we can get fully detailed doors or even entire walls for 3 Li, but people demand low Li! This is probably where the problems arise and why people are kind of gaming the system as their customers demand it with such Li shortage :D (yet I can't believe 32 x 1024 textures won't have more impact than a 4800 tri 1m object - or a 320 tri 5m object ffs LL)

 

 

 

Edited by Codex Alpha
Link to comment
Share on other sites

You are about to reply to a thread that has been inactive for 664 days.

Please take a moment to consider if this thread is worth bumping.

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...