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Sylvia Wasp

Why does (some) mesh do this?

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OK, so I know it's verboten to say anything bad about creators here so I'm excising any information that could identify the creators involved but I have a serious question so I'm going to (carefully) ask it anyway.  

I'm trying to make clothes but I don't know blender so I buy full permission mesh and then try to texture it (an ongoing struggle, lol).  I'm having trouble with some of the meshes and I don't know enough to know what it is.  The picture kind of tells the whole story.  

What I've noticed is that some of the meshes seem to (at various sometimes random times), degrade into a very low detail version.  All I can compare it to is back when we still used sculpties and they went through that tedious multi-level rezzing kind of thing where you had to wait for it to get more and more detailed.  With the meshes though, it sometimes just refuses to go to the "most detailed" level at all.  But then sometimes it does.  

The skirt in the picture (texture removed), often rezzes just fine, but then for days at a time it won't get any more detailed than you see in the picture.  There seems to be no way to force it to rez properly and no way to tell when this will happen. 

Before anyone answers (hoping that they do), I will close off some obvious avenues:

- I'm running a new-ish workstation class 8-core computer with dizzying computational power, dual graphics cards with 6GB of RAM each and 16GB of system RAM.

- I run SL by itself, in a separate account on the computer so that there are no background processes etc. 

- I run with all the settings on Ultra, except I often turn off Ambient Occlusion, and I keep my particle count low because I don't actually care about particles

- All my LOD sliders are at maximum (objects and sculpts at 4.00) except trees, because almost no one even uses Linden Trees anymore. 

- The picture was taken 1,000's of metres in the air, with no major scripts running and nothing that should slow things down.  

- The situation seems random, with the exception of the association with certain creators.  Like, it's not that it happens under heavy load or whatever. 

On the negative side, despite it being one of the fastest computers you can buy, my computer *IS* a Mac, so the terrible, years old code-base that Second Life uses is an issue, but that issue doesn't as far as I know, affect mesh in any way.  The chief downside of running a Mac seems to be just that Second Life graphics are about one third as fast as they would be on a similarly specced Windows box, and of course the dreaded "grass lag" is a big issue because of the alpha.  For those that don't know, a grassy field will lag a Mac into the ground most of the time. 

OK ... 

So what I suspect is that the creator of this mesh (and this happens with a couple of other creators as well) has somehow "built-in" to the mesh a sort of LOD that can't be changed by the user.  Does that make *any* sense?  

I've noticed that certain creators mesh will also disappear completely, or change back into a simple 2D plane, when you back away from them.  This always happens at the same viewing distance, but that distance *differs* from creator to creator.  Like creator A's stuff will vanish from your body if you zoom out to distance X, but creator B's stuff won't do that unless you zoom out TWICE as far.  This seems very consistent from creator to creator.  

Is it possible for the creator to "build in" this sort of thing when making the mesh and is it possible for me, the owner of the mesh to alter it?  

thanks for any help,

Sylvia

 

 

Snapshot_001x.png

Edited by Sylvia Wasp

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I don't know about the creation of mesh and various LOD versions, other than you can upload different mesh models for each LOD level and that's probably being done wrong, but I do think I know why objects drop detail at varying distances from the camera. My experience with sculpties is that an object's LOD is determined by the angle of view it occupies in the scene. A huge sculptie at a great distance will render in full detail while a smaller one (and otherwise identical) will not. I suspect the viewer is doing the same thing with mesh. You'd probably not notice it if the mesh were designed properly.

The same thing, in a different form, happens for particles. If they don't occupy enough angle of view, they're culled. If you want to make truly tiny particles (like stars in the sky), you can't do it by making the particle size small. You must put a very small image in a very large transparent texture, then make the particles as large as possible. The particle system just sees huge particles and so renders them even at great distances. What you see however are tiny, tiny dots.

Edited by Madelaine McMasters

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It looks like the mesh is not set to smooth, but flat. Not that that has much to do with LODs -- a lower LOD could be set to flat, and the high to smooth, but that picture is close enough I doubt any LOD but high would be visible.

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Those squares look a lot like the creator forgot to use the 'smooth' function before uploading. That's a pretty serious oversight.

I *thought* worn, rigged mesh stayed a highest LoD, and running at level 4 should force most things to stay at highest LoD anyway. But other than that, it sounds like LoD issues what with falling off at specific distances.

There are four LoDs which click in at set distances. (More or less, because this is SL and there are always complicating factors.) If the same model is used for a couple of levels, then you won't see a change between them.

Conversely, poorly handled LoDs can mean dramatic changes between them, or a collapse into a mess of triangles. Or a 2d plane or whatever the creator used as the lowest LoD (or let the uploader auto-generate).

These are all things set in stone at the time of uploading. The only way to change them is to make different choices and re-upload.

That's how it works for LoD on unrigged items. I've been taken to task when daring to comment on rigged things, so I'll leave it to others to give their opinions on those.

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1 hour ago, Bitsy Buccaneer said:

I *thought* worn, rigged mesh stayed a highest LoD

Worn rigged mesh uses the same LOD algorithm as any other object in Second Life. The only difference between worn rigged mesh and non rigged mesh is that the attachment uses the size of the entire avatar as its Bounding Box size to calculate swapping the LODs. So even some tiny jewelry will have the effective BB size of the avatar.

This can be quite handy when you, for example, create some full body armor out of several small pieces. You don't have to worry about inconsitent LOD swapps because of the different sizes of the meshes.

Edited by arton Rotaru
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The user can never change the LOD models of any object.  Once the object is
uploaded, its LOD models are fixed.  I think you are probably talking about
increasing your own LOD slider in Preferences, which is just changing the
value of the debug setting *RenderVolumeLODFactor*.  That's just telling
your own viewer to disregard more and more of the low_LOD information it
sees.  It's a way of compensating for the fact that some creators
deliberately upload objects with the lowest LOD information set to zero.
It's their way to get lower Land Impact, but it means that people who don't
mess with the LOD slider will see garbage a lot of the time.  It also means
that when you get beyond the distance where high LOD levels should be
visible, all you will see is a jumble of triangles.

That's a long way of saying that when you see effects like the ones you are
reporting, you are seeing mesh that was not created carefully.  When you
shop, set the LOD sider in Preferences to its default setting (1.25 in the
standard SL viewer) and look at the quality of things you are thinking
about buying.  If they look crummy at even a short distance, don't buy
them. A good 3D modeller ought to be able to make high-quality, low L.I.
objects without sacrificing the quality of the low LOD models in their work.

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58 minutes ago, Rolig Loon said:

The user can never change the LOD models of any object.  Once the object is
uploaded, its LOD models are fixed.  I think you are probably talking about
increasing your own LOD slider in Preferences, which is just changing the
value of the debug setting *RenderVolumeLODFactor*.  That's just telling
your own viewer to disregard more and more of the low_LOD information it
sees.  It's a way of compensating for the fact that some creators
deliberately upload objects with the lowest LOD information set to zero.
It's their way to get lower Land Impact, but it means that people who don't
mess with the LOD slider will see garbage a lot of the time.  It also means
that when you get beyond the distance where high LOD levels should be
visible, all you will see is a jumble of triangles.

That's a long way of saying that when you see effects like the ones you are
reporting, you are seeing mesh that was not created carefully.  When you
shop, set the LOD sider in Preferences to its default setting (1.25 in the
standard SL viewer) and look at the quality of things you are thinking
about buying.  If they look crummy at even a short distance, don't buy
them. A good 3D modeller ought to be able to make high-quality, low L.I.
objects without sacrificing the quality of the low LOD models in their work.

Thanks Rolig, I don't quite understand everything you are saying here, but it's the first useful answer that addresses what I'm asking.  

When I said "can I change this" I meant that because it's full perm mesh and because in some cases I might even have the dae file, that I might be able to import it into blender, change a setting, and then re-upload.  

My LOD slider is always at the max as I said, so I guess you're advising me to set it lower so as to see the objects "at their worst" before I purchase them?  At least I think that's what you're saying, lol. 

I think overall, and considering the price I paid, the skirt in the picture is just badly made.  The thing that bothers me more is that some of the finest made mesh I have from some of the best makers seems to do that "other" thing where it turns into a flat plane at fairly short distances.  I know that we are all essentially naked in SL anyway, but I don't see the value in making my clothes disappear even at fairly short distances.  If you use the camera and zoom somewhere, not only are you naked when you come back, but the clothing won't return until you zoom inside your body, find that "plane" and edit it.  

I still don't really understand what is going on here.  What are the settings exactly that creators are using in Blender or Maya that do this?  Why would it even be done?  

still a bit mystified unfortunately. 

Edited by Sylvia Wasp

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1 hour ago, arton Rotaru said:

Tan lines! B|

:SwingingFriends:

 

Thanks for your support, lol.  Love that song! :) 

I wear tanlines because it's very difficult to find realistic skins (beyond head skins) so it's necessary to augment things in order to heighten the realism.  

Apologies to all for the 1.5 pixels of nipple that I just noticed also.  I will attempt to edit it out. 

Edited by Sylvia Wasp

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2 hours ago, Madelaine McMasters said:

I don't know about the creation of mesh and various LOD versions, other than you can upload different mesh models for each LOD level and that's probably being done wrong, but I do think I know why objects drop detail at varying distances from the camera. My experience with sculpties is that an object's LOD is determined by the angle of view it occupies in the scene. A huge sculptie at a great distance will render in full detail while a smaller one (and otherwise identical) will not. I suspect the viewer is doing the same thing with mesh. You'd probably not notice it if the mesh were designed properly.

The same thing, in a different form, happens for particles. If they don't occupy enough enough angle of view, they're culled. If you want to make truly tiny particles (like stars in the sky), you can't do it by making the particle size small. You must put a very small image in a very large transparent texture, then make the particles as large as possible. The particle system just sees huge particles and so renders them even at great distances. What you see however are tiny, tiny dots.

This would explain the "flat plane" effect I noticed, but not the skirt I guess.  Also what I'm trying to get at is what the setting (during creation) is that causes this to happen as the effect is down to which creator you buy from not just the angular size.  

Like if I wear a top form one creator and a skirt from another, the top will turn flat at one distance and the skirt may not turn flat at all.  If I instead put on a skirt from the same creator as the top, both go flat at the same angular size. 

Edited by Sylvia Wasp

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1 minute ago, Sylvia Wasp said:

My LOD slider is always at the max as I said, so I guess you're advising me to set it lower so as to see the objects "at their worst" before I purchase them?  At least I think that's what you're saying, lol.

Yes, exactly.  Setting your LOD slider to a high setting does have the advantage that you can see more things -- even poorly made ones -- at high LOD.  It has two main disadvantages.  First, as I mentioned earlier, other people who do not also have their sliders set high will see poorly made objects as a few triangles, even though you see them well.  So, the dress that you think looks stunning on you may look like a little floating triangle to the rest of the world.  Second, running your computer with the LOD slider maximized means that your graphics card will always be doing its best to render everything at high LOD, even things at a distance that you really don't need much detail on.  That wastes your system resources and could mean more lag or worse.

7 minutes ago, Sylvia Wasp said:

I still don't really understand what is going on here.  What are the settings exactly that creators are using in Blender or Maya that do this?  Why would it even be done?

These are not "settings" in Blender or Maya.  The importer in SL asks you to define four LOD levels as you import any mesh.  If you accept the default option, the importer creates low LOD models from the single high LOD model that you are importing.  As an alternative, you can create and upload your own separate LOD models -- four mesh models for each object you upload. 

Why would you want to do that?  Because the default system makes some lousy choices, and because you can create models that look much better and have lower L.I. if you do it yourself.  Unfortunately, many SL modelers take the easier way out.  Instead of creating their own LOD models, they use the default but then set the parameters in the importer to zero for the lowest LOD levels.  That keeps the L.I. low, but it encourages people like you to compensate for the missing low LOD models by increasing their own LOD sliders.

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2 hours ago, Bitsy Buccaneer said:

Those squares look a lot like the creator forgot to use the 'smooth' function before uploading. That's a pretty serious oversight.

I *thought* worn, rigged mesh stayed a highest LoD, and running at level 4 should force most things to stay at highest LoD anyway. But other than that, it sounds like LoD issues what with falling off at specific distances.

There are four LoDs which click in at set distances. (More or less, because this is SL and there are always complicating factors.) If the same model is used for a couple of levels, then you won't see a change between them.

Conversely, poorly handled LoDs can mean dramatic changes between them, or a collapse into a mess of triangles. Or a 2d plane or whatever the creator used as the lowest LoD (or let the uploader auto-generate).

These are all things set in stone at the time of uploading. The only way to change them is to make different choices and re-upload.

That's how it works for LoD on unrigged items. I've been taken to task when daring to comment on rigged things, so I'll leave it to others to give their opinions on those.

So ... you're saying that when creating it, they have to provide a "model" for the four levels of detail, and in this case the person has just not provided one?  Because the thing that confuses me about this skirt is that *sometimes* it looks just fine, and at all distances.  

I hesitated to post here about it for ages, because the behaviour is so random I was sure people would just tell me I was looking at it on an especially laggy day or had my settings wrong, etc.  I know it *seems* like that might be the case, but I've tested it over and over (I bought this ages ago) and it seems somewhat random except that it does seem to get "stuck" in this mode at times.  

The reason I did so is that there are basically ZERO good full perm skirt meshes for my body type (Tonic) and the type I want to make clothes for, so I really, really wanted this to work, but sadly it just doesn't.  

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1 minute ago, Rolig Loon said:

Yes, exactly.  Setting your LOD slider to a high setting does have the advantage that you can see more things -- even poorly made ones -- at high LOD.  It has two main disadvantages.  First, as I mentioned earlier, other people who do not also have their sliders set high will see poorly made objects as a few triangles, even though you see them well.  So, the dress that you think looks stunning on you may look like a little floating triangle to the rest of the world.  Second, running your computer with the LOD slider maximized means that your graphics card will always be doing its best to render everything at high LOD, even things at a distance that you really don't need much detail on.  That wastes your system resources and could mean more lag or worse.

These are not "settings" in Blender or Maya.  The importer in SL asks you to define four LOD levels as you import any mesh.  If you accept the default option, the importer creates low LOD models from the single high LOD model that you are importing.  As an alternative, you can create and upload your own separate LOD models -- four mesh models for each object you upload. 

Why would you want to do that?  Because the default system makes some lousy choices, and because you can create models that look much better and have lower L.I. if you do it yourself.  Unfortunately, many SL modelers take the easier way out.  Instead of creating their own LOD models, they use the default but then set the parameters in the importer to zero for the lowest LOD levels.  That keeps the L.I. low, but it encourages people like you to compensate for the missing low LOD models by increasing their own LOD sliders.

Thanks, this sounds like a reasonable explanation.  I have uploaded a few meshes myself for houses and stuff so I should have remembered that.  It seems like because I am forced by my situation into using "cheap" (or cheaply done) full perm meshes, I'm always going to see this.  

I have to disagree about turning the LOD down though.  I will do it as you suggested earlier for "preview" purposes, (to make sure my dress isn't an ugly pile of triangles, lol), that's great advice. But SL is simply too ugly and wonky at low LODs to be worth playing the whole game that way (IMO of course).  

I'm new to mesh, but I've been playing SL for ages and the one thing I know for certain is that when it comes to creation, it's a mistake to tailor stuff to the lowest common denominator or computer or to use anything but the highest settings your computer can stand for viewing.  I think the Lindens copious advice to that effect is both biased and in error as well.  "Good enough" is a moving target in SL and aiming at it only causes grief (again IMO of course).  

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1 hour ago, arton Rotaru said:

Worn rigged mesh uses the same LOD algorithm as any other object in Second Life. The only difference between worn rigged mesh and non rigged mesh is that the attachment uses the size of the entire avatar as its Bounding Box size to calculate swapping the LODs. So even some tiny jewelry will have the effective BB size of the avatar.

Maybe my previous understanding of it was better than I thought, at least until it was cough improved through the forum. :SwingingFriends:

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2 minutes ago, Bitsy Buccaneer said:

Maybe my previous understanding of it was better than I thought, at least until it was cough improved through the forum. :SwingingFriends:

I'm getting more and more lost! esp. with people posting this: :SwingingFriends:

Does that mean what I think it means? :) 

Anyway, I think to sum up my questions and the answers ... I would say it seems that cheap/lazy mesh makers are flooding the market with lazy products (no names mentioned) and others who are better at mesh are being taken in by the Linden advice to make everything simple so people with awful computers can still see it.  The bottom line is that I can't do anything about it, until quality mesh makers want to step up and make full perm meshes for Tonic.  

I'm not sure why they don't.  It's a better, higher quality, body than most on the market.  From what I've seen only Maitreya is (slightly) better. 

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10 minutes ago, Sylvia Wasp said:

I have to disagree about turning the LOD down though.  I will do it as you suggested earlier for "preview" purposes, (to make sure my dress isn't an ugly pile of triangles, lol), that's great advice. But SL is simply too ugly and wonky at low LODs to be worth playing the whole game that way (IMO of course).

Sadly, I agree.  I've been here more than 10 years myself.  I will always create things to be viewed at the standard default setting, and I will only buy things that other creators have made with that in mind. [To be honest, I am basically a scripter.  My own modeling skills are modest, but I hang around with some incredibly skilled mesh modelers who have taught me to avoid low quality workmanship.]  That choice guarantees that other people will see my objects as well as I can without being forced to use a high slider setting and sacrificing their frame rate and image quality.  Because many creators are not as thoughtful -- or simply don't know any better -- I see some of their work as garbage in my viewer as a result.  It's my choice.  By opting for the standard setting, I get better overall performance and the warm satisfaction of knowing that I am not supporting low-quality mesh products in world.  I agree that if you make the same choice, you may also see some more garbage, and that may be unacceptable to you.  When you ask thoughtful questions like the ones you raised here, though, all I can do is draw a parallel to shopping in RL:  If you buy your clothes at Wal-Mart, don't be surprised when they don't have the quality you would expect at Macy's.  ;)

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8 minutes ago, Sylvia Wasp said:

I'm getting more and more lost! esp. with people posting this: :SwingingFriends:

I love these two little swinging guys. That's why I post them a lot in the first place. ^_^ To me they have a wide range of use cases as well. From friendly, to sarcastic. ^_^

Btw. I liked the uncensored image more. :SwingingFriends:

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13 minutes ago, Rolig Loon said:

Sadly, I agree.  I've been here more than 10 years myself.  I will always create things to be viewed at the standard default setting, and I will only buy things that other creators have made with that in mind. [To be honest, I am basically a scripter.  My own modeling skills are modest, but I hang around with some incredibly skilled mesh modelers who have taught me to avoid low quality workmanship.]  That choice guarantees that other people will see my objects as well as I can without being forced to use a high slider setting and sacrificing their frame rate and image quality.  Because many creators are not as thoughtful -- or simply don't know any better -- I see some of their work as garbage in my viewer as a result.  It's my choice.  By opting for the standard setting, I get better overall performance and the warm satisfaction of knowing that I am not supporting low-quality mesh products in world.  I agree that if you make the same choice, you may also see some more garbage, and that may be unacceptable to you.  When you ask thoughtful questions like the ones you raised here, though, all I can do is draw a parallel to shopping in RL:  If you buy your clothes at Wal-Mart, don't be surprised when they don't have the quality you would expect at Macy's.  ;)

Thanks, you've been really helpful.  I just wish "Macy's" would carry clothes for my body type (a RL problem as well, lol)

Edited by Sylvia Wasp

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8 minutes ago, arton Rotaru said:

I love these two little swinging guys. That's why I post them a lot in the first place. ^_^ To me they have a wide range of use cases as well. From friendly, to sarcastic. ^_^

Btw. I liked the uncensored image more. :SwingingFriends:

Thanks, I thought that was what they were.  

I've gotten into (mild) trouble before over that sort of thing though, people are prudes and SL has a lot of people who go bananas if they see your (cartoon) nakedness for some reason.  It's kind of crazy that I could go to the beach topless in RL, but in SL I once got a three day suspension because someone I don't even know saw my boobies in a "G" area.  

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9 minutes ago, Sylvia Wasp said:

 It's kind of crazy that I could go to the beach topless in RL, but in SL I once got a three day suspension because someone I don't even know saw my boobies in a "G" area.

That's one more reason why I don't be on Facebook, no boobies. ^_^

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29 minutes ago, Sylvia Wasp said:

It's kind of crazy that I could go to the beach topless in RL, but in SL I once got a three day suspension because someone I don't even know saw my boobies in a "G" area.

Heh ... One more reason why it's a good idea to buy quality mesh. "Apex Clothing Ltd:  Our clothing keeps you out of jail."   :P

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22 minutes ago, Sylvia Wasp said:

So ... you're saying that when creating it, they have to provide a "model" for the four levels of detail, and in this case the person has just not provided one?  Because the thing that confuses me about this skirt is that *sometimes* it looks just fine, and at all distances.  

I hesitated to post here about it for ages, because the behaviour is so random I was sure people would just tell me I was looking at it on an especially laggy day or had my settings wrong, etc.  I know it *seems* like that might be the case, but I've tested it over and over (I bought this ages ago) and it seems somewhat random except that it does seem to get "stuck" in this mode at times.  

The reason I did so is that there are basically ZERO good full perm skirt meshes for my body type (Tonic) and the type I want to make clothes for, so I really, really wanted this to work, but sadly it just doesn't.  

Four LoD levels are required.

The mesh uploading system has an auto-generate feature which can be used to make one, two, or three of the models automatically. Sometimes these are alright. Often they are less than optimal visually. They tend to be responsible for the messes we sometimes see as mesh collapses.

A second option is to create the models in the 3d software.

A third option is to use 'the file above' (the previous lod level). In that case, there is no change between those specific levels.

-------

arton is one of two people most responsible for my managing to scale the cliff face that is Blender's learning curve. he likes the swinging people, so it was only appropriate to use that in replying to his reply to me. sorry if it confused you.

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1 hour ago, Sylvia Wasp said:

But SL is simply too ugly and wonky at low LODs to be worth playing the whole game that way (IMO of course).

That's only because there still is so much poorly made mesh out there. Good mesh will look good even at lower settings. And as Rolig said, increasing the LoD can seriously reduce any computer's performance. How much, depends on the surroundings, sometimes it's barely noticeable but sometimes it can reduce the frame time by as much as 50%, maybe even more.

Or to put it another way: with LoD factor 4 you need a fairly high end game computer to get the same performance as you should have gotten out of a mid/low range desktop computer if it wasn't for crappy mesh makers.

The problem with the skirt in the picture doesn't seem to have anything to do with LoD though. Pamela's probably right that the maker made it with flat rather than smooth normals, forcing him/her to use four times as many polys as necessary and still not get it smooth.

 

4 hours ago, Sylvia Wasp said:

OK, so I know it's verboten to say anything bad about creators here

We are not allowed to speak badly of any named person, creator or not. Complaining about poor makers in general is ok.

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Actually, but not quite sure...

It could be that the mesh itself is not as smooth as it should, but it could have been baked with smooth, meaning that, the person uploaded a lower LOD model, but made the Ambient Occlusion map/shadow bake with a higher resolution, so it might be that after you place it a texture you won't notice the squares that much... Just assuming....

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I noticed that quite a few creators who use Blender don't actually appear to know about smooth shading...

Quite a few furnitures I bought where, on close inspection, all the polygons are "faceted" like that.

On top of being ugly it actually is slower to render.

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