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GypsiesSoul

LOD ( level of detail ) = Items disappearing when zoomed out?

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Posted (edited)

Hi can we please talk about LOD (Level of Details).

Im focusing mainly on the clothes and attachments that you wear on your body, not external items like furniture/houses/environment items.
I hope im getting this correct.

There's two type.
TYPE 1: The inherent LOD in the item itself.
(this LOD is controlled by creator of the item)

TYPE 2: the LOD settings option in your viewer, which
default is set at 2.0, and 4.0 being highest.
(this LOD is controlled by your viewer's preferences)


If the item has bad inherent LOD, when you zoom out even just for a *little* bit of distance,
the item disappears! And thats not very good, right?

I tend to associate low quality items having bad inherent LOD because I noticed
most free gifts tend to have bad inherent LOD, and a lot of gachas (cheap prices) tend to have bad inehrent LOD.

when I first wasnt aware of LOD's, and I have bought store items that costed a lot of lindens and ended up having bad inherent LOD, I mentioned this to some creators of the item disappearing,
they would recommend me to change my own viewer's LOD setting options to the highest setting of 4.0 (in order for the item to be visible from a long distance).
But this is NOT a good recommendation because it actually lags/stress out your computer, right?
This recommendation forces your computer screen to make all these surrounding far distanced items be visible, which isnt necessary. so thats why it lags.

SO I end up disappointed, detaching the item and not using it, and feel like I wasted my money on the item. I still keep my LOD settings option at the default 2.0.
Because this default 2.0 is already a good setting. And a lot of people have this setting by default.

Why should the consumers have to change their own viewers LOD settings options to compensate for the bad inherent LOD in the item?

One of my fear is many  creators/designers have their own viewers's LOD settings options set at 4.0,
so when they create an item to sell, they forget that many people wont be able to see the item like how they see it .
So the creators end up making the inherent LOD of the item very low  (bad quality) because they wrongly THINK people will be able to see the item just fine.


So I am  wondering why creators try to make as low inherent LOD as possible?
After some searching around, I found some person explaining how creators think a low inherent LOD (disadvantage) would also have Low Impact (benefit).
But he also explained how that there are actual ways to create an item with Higher inherent LOD(benefit) and have low land impact (benefit) which would be a win-win situation.
The person said not many creators know about these GOOD techniques.
Im not sure what the techniques are though???

Or perhaps there are other reasons why creators are creating these inherent low LOD items? easier to make such as for gachas?

But anyways now im extremely picky about items I buy because Im scared of bad inherent LOD's.

 

 

 

Edited by GypsiesSoul
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Posted (edited)
2 hours ago, GypsiesSoul said:

Im focusing mainly on the clothes and attachments that you wear on your body, not external items like furniture/houses/environment items.
I hope im getting this correct.

They both work in similar ways, so don't worry about using either as an example. I'm going to lean more towards rezzed objects as that's a little easier for me to demonstrate later.

Quote

There's two type.
TYPE 1: The inherent LOD in the item itself.
(this LOD is controlled by creator of the item)

TYPE 2: the LOD settings option in your viewer, which
default is set at 2.0, and 4.0 being highest.
(this LOD is controlled by your viewer's preferences)

There are a set of 4 LOD models for every mesh item. 1 Main and 3 increasing lower versions.

These LOD meshes are setup when the mesh item is uploaded. When uploading a mesh you can either specify separate models for each LOD (that you have presumably made when you made the full detail version) or allow the mesh uploader to generate lower poly models for you, I bet you can guess which method results in screwed up balls of triangles. These LOD models go a long way to determining the objects final 'weight' (Li or ARC).

The LOD slider in the viewer controls how quickly they are used. A low setting will cause the models for lower LODs to be swapped in sooner.

Quote

If the item has bad inherent LOD, when you zoom out even just for a *little* bit of distance,
the item disappears! And thats not very good, right?

If the item vanishes, then that's because that mesh has nothing you can see for the LOD model the viewer is trying to show you.

This is often caused by creators choosing to sacrifice lower detail models in order to get a lower object weight and/or because at that LOD the mesh uploader wants to turn them into junk.

Quote

I tend to associate low quality items having bad inherent LOD because I noticed
most free gifts tend to have bad inherent LOD, and a lot of gachas (cheap prices) tend to have bad inehrent LOD.

Often the creators have pushed the sliders around in the uploader to get a specific Li score rather than preserve the objects detail. This is why decorative gatcha clutter is almost always 1 Li regardless of how complex the high detail model is.

 

Quote

they would recommend me to change my own viewer's LOD setting options to the highest setting of 4.0 (in order for the item to be visible from a long distance).
But this is NOT a good recommendation because it actually lags/stress out your computer, right?

Correct!

The viewer is trying to show you less detailed models for things when they are smaller on your screen and/or further away. This is required to keep those frame rates up. No point rendering geometry that is smaller than a pixel on your screen (something that can be totally normal in SL .. and then people complain it's slow .. smh)

Feel free to join me in thinking some very choice thoughts about creators who tell people to crank up their LOD settings, perhaps by using a debug setting .... <now>

Quote

SO I end up disappointed, detaching the item and not using it, and feel like I wasted my money on the item. I still keep my LOD settings option at the default 2.0.
Because this default 2.0 is already a good setting. And a lot of people have this setting by default.

Demo everything.

Quote

Why should the consumers have to change their own viewers LOD settings options to compensate for the bad inherent LOD in the item?

They shouldn't. 

Quote

One of my fear is many  creators/designers have their own viewers's LOD settings options set at 4.0,
so when they create an item to sell, they forget that many people wont be able to see the item like how they see it .
So the creators end up making the inherent LOD of the item very low  (bad quality) because they wrongly THINK people will be able to see the item just fine.

You have to pay for land. Land comes with a certain amount of Li (previously prims). So you are paying for the amount of stuff you can have out. This puts pressure on creators to get the amount of Li it uses to a bare minimum .. like 1 .. whatever it is, it must be .. 1 (or less than 1!)

Firestorm is the most popular third party viewer, it's object detail slider in prefs goes to double what the official (and other) viewers go to. Creators use Firestorm with their slider set to max (they either don't know it's actually double or don't care). This means their viewer doesn't show the lower detail models till much later than people with a lower setting.

This double the max LOD was done because of of sculpt maps. It was found that with a higher LOD and other tricks, you could get a LOT of geometry into a single sculpt. These sculpts looked like junk everywhere, and people were told to crank up their settings to fix them. Mesh totally superseded sculpts but the desire for super low Li is still a driving factor.

Can you see how we end up in the current mess.

 

Quote

So I am  wondering why creators try to make as low inherent LOD as possible?
After some searching around, I found some person explaining how creators think a low inherent LOD (disadvantage) would also have Low Impact (benefit).

Tighter or missing LOD models makes an object have lower 'weight', and customers want that.

They find out afterwards what that means, as you have.

Quote

But he also explained how that there are actual ways to create an item with Higher inherent LOD(benefit) and have low land impact (benefit) which would be a win-win situation.
The person said not many creators know about these GOOD techniques.
Im not sure what the techniques are though???

Probably more information that you were after ... 

 

It's possible to make LOD models by hand (when you make the full detail thing), and get a lower final 'weight' than the default mesh uploader AND an object that degrades smoothly.

Some creators who make their meshes from scratch do this, the skill set required to do this is a subset of the skills needed to make the original model,  so it's more about time and desire. It does take time and iterative testing and refining the models (tweak it, upload on beta grid, zoom out, squint, back to blender, adjust, upload again), but once you get a feel for it it can go much smoother

Pictured is a window box I recently did, it's a simple model so easy to see how the geometric complexity changes from most detailed at rear to least at the front. This object comes out to 0.5 Li when rezzed.

sftp2xA.png

 

 

Some creators use sculpting or clothing design tools, other modelling software to create their meshes and don't have the control in that application to make or export LOD models. They do not have the skills to create a mesh by hand and are therefore unable to do this themselves.

Here is what the mesh uploader does to my box

iZqwXKF.png\

Looks like it's been in a fire... doing this for an item with a complex shape and the mesh uploader will turn it into triangle spaghetti very quickly

If the uploader makes a really bad mess (and most models end up in a mess fairly quickly) , then the creator may well decide to just drop the triangle count as low as it will go, the triangle spaghetti vanishes (no point anyone seeing it anyway), the object will cease to exist when that LOD comes up for rendering and the final thing has a nice low Li.

 

It's important to note that specialized modeling tools exist because hand making certain things in the same way I made that box, is exceptionally complicated, bordering on insanely difficult. Half the reason old 3d looks bad is because we didn't have awesome specialized tools. Also! Making LOD models for more organic shapes is obviously harder than simplifying a box.

 

It is entirely possible to take the mesh as output from your favorite "magical awesome tool" and then make your own lower triangle versions so the uploader doesn't make it into mush while achieving an acceptable balance between detail, graceful desegregation, and cost to rez in world.

Your modeling tool may have tools to help built in for you, most 3d modelling applications have something that does similar 'decomposition' as the uploader but with nicer results.

Doing it by hand can add a fair amount of extra work to your workflow depending on how crazy your original model started out .. this may mean the first step is some retopology, and can involve literally remaking your model by hand using the original as a template. Again, not super hard, just time consuming if you're new to it, and there are some awesome tools that can do it for you (or at least the bulk of the work)

 

BUT 

 

This is all for a thing that will only be sold for a buck because people think 300L is a lot of money.

 

 

 

 

Edited by CoffeeDujour
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2 hours ago, GypsiesSoul said:

I mentioned this to some creators of the item disappearing,
they would recommend me to change my own viewer's LOD setting options to the highest setting of 4.0 (in order for the item to be visible from a long distance).

Worse yet, there are still tons of creators out there that will tell you to use the Debug Settings to set it to 8.0.  

 

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2 hours ago, GypsiesSoul said:

default is set at 2.0, and 4.0 being highest.

Actually, 1.0 is normal default. Think of it as a multiplier for the range at which each LOD model is rendered. At 1.0 it renders at the default ranges. 

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In the stock Linden Viewer (and Catznip) the slider starts at 1.0 (low) and goes to 2.0 (high). It is a linear slider (half way, 'medium' is 1.5)

In Firestorm the slider starts at 1.0 and goes to 4.0, it does not scale linearly. Exactly half way, 'medium' is 2.625

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A "fun" side effect of this is your clothes will disappear if someone pulls their cam back away from you. I was aware that this happened for a long time but never knew until now just why it happened. We tend to joke about it now and then when there is a lull in chat at the club where I work.

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This is something I try to get right with the stuff I make, but two things to bear in mind:

1: If you're wearing a rigged mesh, such as mesh clothes. the switching distances are the same for all items, and are based on your body size. A small item might otherwise switch detail level rather too soon.The switching distance may be too high, some people call it a bug in the calculation, but that's the way it is.

2: Some objects have several distinct mesh parts, and some parts will switch long before others. It's fairly common with wheels on vehicles. It can be made a lot less obtrusive by doing something like setting Medium LOD the same as High LOD

Getting things right doesn't depend on making specific LOD models, though the automatic generation of lower LOD can make some horrible choices.

For ordinary rigged mesh clothing, the Low and Lowest LOD models can be very simple, nobody will ever see them as anything more than a blob at the distances they're visible.

 

There's a similar system for textures, all automatic. Using several materials from the same texture  make the choices less clear, but it does mean that big textures can be easily wasted. It all works from the size a texture will appear in your viewer. A lot of 1024 textures are wasted.

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Posted (edited)
16 hours ago, Rhonda Huntress said:

Actually, 1.0 is normal default.

Normal LoD factor for the standard SL Viewer is 1.125 and has been so for several years. I think Low and Low+ had 1.0 until recently but now it has 1.125 even for Low graphics and only switches to 2.0 for Ultra. You can reduce the LoD factor to 1.0 in the advanced preferences settings and all the way down to 0 in the debug settings.

This is for rezzed objects and for worn prims, sculpts and rigid meshes. The entire LoD system is broken for fitted mesh and there are only some very special and rare occasions you see the LoD model for those at all.

I optimize for LoD factor 1.0 anyway because we need a little bit margin of error to compensate for the inevitable LoD swap delays.

 

16 hours ago, CoffeeDujour said:

In the stock Linden Viewer (and Catznip) the slider starts at 1.0 (low) and goes to 2.0 (high). It is a linear slider (half way, 'medium' is 1.5)

In Firestorm the slider starts at 1.0 and goes to 4.0, it does not scale linearly. Exactly half way, 'medium' is 2.625

I think Firestorm lets you reduce it to 0 in the quick preferences and you can do that on any viewer through the debug settings. With LoD fctor 0 all items are rendered at lowest LoD regardless of their size or distance.

This is a little bit worrying btw. In theory it's a good idea since it allows people with serious performance problems to cut down their render lag to an absolute minimum but with all the butchered LoD models around it doesn't really work that way - not if you want to see anything even remotely resembling a credible virtual reality scene. Even worse, there seem to be more and more builders who over-strengthen their LoD models to keep all the details intact even at LoD factor 0. This of course effectively means the entire LoD system is disabled and everybody's computers are forced to render everything in full detail whether they can handle it or not and whetehr those details are needed or not.

Edited by ChinRey

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19 minutes ago, ChinRey said:

I think Firestorm lets you reduce it to 0 in the quick preferences and you can do that on any viewer through the debug settings. With LoD fctor 0 all items are rendered at lowest LoD regardless of their size or distance.

This is a little bit worrying btw. In theory it's a good idea since it allows people with serious performance problems to cut down their render lag to an absolute minimum but with all the butchered LoD models around it doesn't really work that way - not if you want to see anything even remotely resembling a credible virtual reality scene. Even worse, there seem to be more and more builders who over-strengthen their LoD models to keep all the details intact even at LoD factor 0. This of course effectively means the entire LoD system is disabled and everybody's computers are forced to render everything in full detail whether they can handle it or not and whetehr those details are needed or not.

 

This happens mostly for attachments, the uploader sets all the LOD meshes to the same high detail one, maybe lets the very lowest model degrade some.

PLWZNaJ.png

... and now we know why this hair has an ARC of 22061

 

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4 hours ago, ChinRey said:

Normal LoD factor for the standard SL Viewer is 1.125 and has been so for several years. I think Low and Low+ had 1.0 until recently but now it has 1.125 even for Low graphics and only switches to 2.0 for Ultra. You can reduce the LoD factor to 1.0 in the advanced preferences settings and all the way down to 0 in the debug settings.

When I click the Rest to Default button it goes back to 1.000

31780ed50212a446edaf21828c19beeb.png

Granted there are ways to change this value without going to the debug settings such as selecting ultra graphic settings but everything is normalized at 1.  The default unit is one unit, so to speak.  It is fairly arbitrary and means about as much as one knob goes to 10 while another goes to 11 but that's just some undefined way of showing where on the dial you are. It starts at 1.

 

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1 hour ago, Rhonda Huntress said:

When I click the Rest to Default button it goes back to 1.000

That doesn't surprise me. The debug settings functions probably haven't ben updated in ages.

But I was talking about the graphics settings in the preferences. The seven standard graphics settings there all set LoD factor at 1.125, except Ultra which sets it to 2.0:

image.png.1ea63a022a3f4821fe80017d7f37e288.png

image.thumb.png.dfe300be1bf805126c06c4c2388dd9ab.png

image.thumb.png.2f2666db96ec9bd0867205cee063ecea.png

In the advanced preferences (it's called , you can change it between 1.0 and 2.0

image.thumb.png.4e6825517a13413315c94413bb2e1672.png

image.thumb.png.77352155494c925f01fc24caa5a36bf3.png

 

1 hour ago, Rhonda Huntress said:

It is fairly arbitrary and means about as much as one knob goes to 10 while another goes to 11 but that's just some undefined way of showing where on the dial you are. It starts at 1.

It's not arbitary, the number is an actual factor used in the swap distance formula.

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