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LOD fail of the week


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Level of detail fail of the week.

lodfail0.png.ce6d742c8f2d64d9bf436994f04471b0.png

Elaborate vault door to hide what's inside.

lodfail1.png.5694634afa54fb709b00bfa33078e812.png

Back off a little, and you can see into the vault.

 

lodfail2.png.0ef156853e517a4900d44e065e4a95d8.png

Back off a bit more and the whole vault door and frame disappear.

This is why blindly using "Decimate Triangle" in Blender to create lower level of detail models with very small numbers of triangles is a big mistake.

(This vault is for sale on Marketplace for L$3,990.)

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I found that MP listing.
In fairness to this creator, they do not suggest setting RenderVolumeLODFactor to a stupidly high setting.
In the package, they provide a low LOD & a high LOD version of the vault & make a note that if you need to see the door from further away, to use the high LOD model.
The low LOD door is only 1 LI.  the high LOD door is 35LI.

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On 2/9/2018 at 7:15 PM, Whirly Fizzle said:

In fairness to this creator, they do not suggest setting RenderVolumeLODFactor to a stupidly high setting.

But.. but... but... :ph34r: I have an oberaffentittengeil (that's awesome in German) gaming rig with two overclocked Titan SLI video cards and 128 GB of DDR9 RAM and four 8K monitors, and if I want to set my RenderVolumeLODFactor over 9000 i should be allowed to without the nanny state killing all my fun. :ph34r: 

(("nanny state" was a hint I am joking, yeah?))

 

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On 2/9/2018 at 12:15 AM, Whirly Fizzle said:

I found that MP listing.
In fairness to this creator, they do not suggest setting RenderVolumeLODFactor to a stupidly high setting.

The low-LOD model could be a grey flat plane. Maybe with a picture of the vault door. But one random triangle and a big opening is a fail. Low-LOD models should at least cover the area of the object. Some people are pushing triangle decimation way too far. It's the wrong tool for the job when you're down to single digits of triangles.

Unreal Engine's creator tools have a built-in feature for creating impostors. It renders the object from many angles and builds a sprite with the rendered images pasted on. SineSpace creators have that available.

Edited by animats
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4 hours ago, animats said:

The low-LOD model could be a grey flat plane. Maybe with a picture of the vault door. But one random triangle and a big opening is a fail. Low-LOD models should at least cover the area of the object. Some people are pushing triangle decimation way too far. It's the wrong tool for the job when you're down to single digits of triangles.

Unreal Engine's creator tools have a built-in feature for creating impostors. It renders the object from many angles and builds a sprite with the rendered images pasted on. SineSpace creators have that available.

I thought said platform uses the Unity engine.

Other than that, this is the Second Life forums. We discuss how to do stuff in Second Life, within it's capabilities and limitations.

I'm sure there are quite a few engines out there which can do a ton more cool things than Second Life does. Doesn't help me creating for Second Life though.

I'd recommend you do some feature requests on the Jira if you want to have certain features added to Second Life.

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3 hours ago, arton Rotaru said:

Other than that, this is the Second Life forums. We discuss how to do stuff in Second Life, within it's capabilities and limitations.

I'm sure there are quite a few engines out there which can do a ton more cool things than Second Life does. Doesn't help me creating for Second Life though.

SL imposter generation could be done by a script for Blender. Most of those awful triangle decimations seem to come from Blender, so a Blender-based tool makes sense. Something like this:

Blender's renderer can render both isometric (infinite camera distance) and RGBA, so you can get out a clean PNG for the impostor texture, with transparency where appropriate. Render from the normal to the center of each face of the impostor, to get a texture for that face. Maybe render twice per face; once with diffuse light for the diffuse texture, and once with a single straight-on light for specular. Or not. Upload the texture for each face, and bake into one texture.

I've used Blender, but not recently. Someone current with Blender could probably do this easily.

You have to be aware of what the competition is doing, or you get behind and become irrelevant.

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1 hour ago, animats said:

Most of those awful triangle decimations seem to come from Blender, so a Blender-based tool makes sense.

These are just done during the import process of a mesh with the SL viewer itself. People don't even bother to fire up more advanced decimation functions.

1 hour ago, animats said:

You have to be aware of what the competition is doing, or you get behind and become irrelevant.

That 'you' would be Linden Lab. That's why I recommend using the SL Jira for proposals, or feature requests.

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9 hours ago, animats said:

Unreal Engine's creator tools have a built-in feature for creating impostors.

Second Life has a feature that does exactly that completely automagically! The only minor limitation is that it's only used for avatars and isn't avalable for rezzed objects.

 

1 hour ago, animats said:

Most of those awful triangle decimations seem to come from Blender,

No, it's done by the uploader and has nothing to do with what software is used to create the mesh.

Take a look at the picture I posted in this thread yesterday. This is how much of Second Life looked around the time mesh was introduced and apparently Linden Lab didn't see anything wrong with it. It was only after massive and prolonged pressure from prominent user groups they eventually agreed to do some half-hearted attempts at cleaning up.

This has everything to do with LoD fails because it illustrates the mindset of the people who developed mesh for Second Life: no aesthetic sense whatsoever and they honestly believed that something like that picture was a sellable product. So for LoD models, they implemented Geometric Level Of Detail and set it to chop off a quarter of the geometry for each level.

I know it's hard to believe, but those LoD failures are actually how the Linden Lab developers and bosses at that time envisioned mesh to be in their muddled minds.

Edited by ChinRey
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18 minutes ago, ChinRey said:

No, it's done by the uploader and has nothing to do with what software is used to create the mesh.

While I agree that the most LIKELY cause of these type of problems are "zeroing out" at the lower levels (and OMG sometime the THREE LOWER LEVELS) the decimate tool can ALSO cause these issues if NOT TESTED (which apparently very few folks do).  Some folks DO make custom LODs that are just plain horrible. 

I would say that the door if made well with long LOD viewing could be around eight maybe? Just depends on how long you want that viewing to be which is very much a user call. 

 I am assuming that the OP didn't listen to all the 

"NEVER BUY WITHOUT A DEMO" advice that comes up a few times a week here. 

So sadly, that's the way it is. The option is of course to use the "primmy" version. At least there IS a primmy version :D. 

I have never paid $4000 for ANYTHING and certainly wouldn't without seeing and testing the item inworld. 

 

EDIT: We are all assuming that the photos shown are of the low LOD model and NOT the high LOD model. That wasn't exactly mentioned in the OP. 

Edited by Chic Aeon
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1 hour ago, Chic Aeon said:

I would say that the door if made well with long LOD viewing could be around eight maybe?

Not sure what you mean by that but if you mean land impact, this is a 1-5 LI build with LoD optimized for LoD factor 1.

 

1 hour ago, Chic Aeon said:

While I agree that the most LIKELY cause of these type of problems are "zeroing out" at the lower levels (and OMG sometime the THREE LOWER LEVELS) the decimate tool can ALSO cause these issues if NOT TESTED (which apparently very few folks do).

It can, yes but this does not look like a Blender decimate error. Blender decimates by vertices and this is very clearly done by chopping off polys. Also, notice how small details are kept in the LoD models while big surfaces are removed. As far as I know, GLOD is the only decimation algorithm poor enough to do something as insanely stupid as that.

That being said, I would never use Blender's decimate modifier to generate LoD models either because I don't think it's good enough. I do use the limited dissolve function but very carefully.

Edited by ChinRey
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1 hour ago, ChinRey said:

No, it's done by the uploader and has nothing to do with what software is used to create the mesh.

In the viewer, or back at the server?

Edited by animats
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19 hours ago, animats said:

Unreal Engine's creator tools have a built-in feature for creating impostors.

It's Epic Games you're talking about, not LL. The pioneers of online gaming, those who for first came up with the whole idea of a game engine with modding in mind, many years before the others (the first Unreal Tournament online, dating back 1995 or 1998, can't remember right now). They've got a boatload of experience and knowledge in the field and that's why all other game engines run after UnrealEngine's features. Whatever plug in or scriptset in Unity that tries to port some of the most useful feature found in UE4 just doesn't deliver at the same level, beginning from Unity's "PBR" shaders (blinn/phong model based when the industrial standard uses ggx AKA Disney's tail fall off version).

 

10 hours ago, animats said:

SL imposter generation could be done by a script for Blender. Most of those awful triangle decimations seem to come from Blender, so a Blender-based tool makes sense.

Decimation or Reduction in different softwares will always lead to similar results, may be better than the viewer's GLoD but still similar polygon reduction methods. A scripted solution to create just the lowest LoD as impostor is a good idea though

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1 hour ago, OptimoMaximo said:

Decimation or Reduction in different softwares will always lead to similar results, may be better than the viewer's GLoD but still similar polygon reduction methods.

Oh no, it's a very different method. Both Blender's decimation tools removes vertices, merging smaller triangles into fewer bigger ones. GLoD removes triangles, leaving holes in the model.

GLoD is very focused on retaining the contours of the model (and it tends to a rather strange view of what is needed for that) and the SL implementation of it at least gives very high priority to keeping the object's overall size. The result is that GLoD tends to keep triangles close to the outer edges (along all three axises) and remove triangles closer to the center of the object. Animats' second oicture is very typical of what GLoD produces: tiny triangles close to the outer edges (such as the turning wheel) are kept while large surfaces clsoer to the obejct center (such as the actual door) are removed. This is very typical for GLoD and I don't know of any other decimation algorithm that is quite as bad as it.

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18 minutes ago, ChinRey said:

Oh no, it's a very different method. Both Blender's decimation tools removes vertices, merging smaller triangles into fewer bigger ones. GLoD removes triangles, leaving holes in the model.

You got me the wrong way: reduction or decimation will lead to similar results because the methods are similar (although limited anyway), still better than GLoD

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38 minutes ago, OptimoMaximo said:

You got me the wrong way: reduction or decimation will lead to similar results because the methods are similar (although limited anyway), still better than GLoD

Oh. ;)

 

Is this when i finally have an excuse to use this emoticon?:

:SwingingFriends:

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