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Rya Nitely

Land Impact and LOD Factor Compromise

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I'm building ruined walls that have quite a bit of detail per prim - broken bricks, windows, doors etc. When I view them with an LOD factor of 4 they look great from a distance. However when using an LOD factor of 2, the walls breaks down very quickly to medium LOD, which is not so attractive - I made it myself. A more detailed medium LOD increases the Land impact significantly. I found that keeping the texture looking as similar as possible in each LOD level helps to preserve the look. But I don't know if I should improve the shape and compromise the low LI for people using a lower LOD factor.

So, I am interested in knowing if creators here cater for those who use an LOD factor of less than 4 when building?

 

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I would build for 2, because that's the maximum that prefs allow without delving into the debug settings. Not everybody is savvy or confident enough to fiddle around with that.

What's your lowest LOD like? It needs to be extremely cut down, to the point of being as close to cube or plane as possible.

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I'm going to build for 2. I was considering this and you've confirmed it :).

I only build high, medium and low LODs. My Low LOD is practically a cube, and the medium is a cube with about 4 or 5 extra vertical edges to give it some shape at the top. I  use the generated lowest and select 0 so that it usually turns out about 3 to 5. I don't think it matters if the item disappears at some point when you cam out.

Thanks for your advice :)

Edit: Oh when I said build for 2, I meant build two different sets - one low LI ( LOD factor = 4) and one higher LI (LOD factor = 2). It's just all so complicated now. I'll have to include both types in the package.

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 >>> I found that keeping the texture looking as similar as possible in each LOD level helps to preserve the look.
You got your answer right there, all by yourself =)

If it is not a huge structure that needs to be seen from very far, the lowest 2 LODs should really significantly 'decrease' in the amount of used polygons / tris.

And as you figured already, keeping these (and also the medium) higher -  increases the landimpact quite a bit.

The texture is your biggest tool here. Loose more and more geometric detail and rely on the texture to fulfill the visual reference. In some cases you can even think of having just 1 polygon planes, where the texture draws a transparent cutout of the object, placed on the same UV in a corner and small in detail. That is the most extreme you can go to cut something down on its lowest level.

You should not worry too much about how things look from further away in terms of the fine details.

And not only you personally, also the others will have a better viewing experience when the object doesn't force high polycounts to be rendered onto them, even when being on a further distance. Some may run on LOD setting of strength 4 and most probably on 2 so building for the 'average' is always the best choice.

But the average user also mostly does not have a high end computer. So optimization and rendercost should always be more important then aesthetics : )

With big structures like walls I'd stick with everything that keeps the 'outter shape'  (the visual outline) at the medium LOD intact, but remove all fine details, and go noticeably down for the last 2.

If there are not many other structures around or to be expected. And you just have maybe a main building and those walls taking the most place on the region, you can of course depending on such cases decide to go for heavier models in the LODs and just accept the higher landimpact.

Edit: your idea to build 2 sets is one possible solution too.

But keep in mind if its something that is placed where many users can come and go, then possibly most owners won't remove and replace their walls all the time to give every visitor the best experience.
So maybe a 'good structured' build that  is good for no matter who ( regarding the settings and computer)  is looking at it might save you some work and do just as good as 2 versions. =)

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I'm going to concentrate more on the texture. Thanks for emphasising this.

I also just realised when reading your reply that I do have a high end computer and use a draw distance of 380, where many people would be using 128 meters, so the walls would fade out faster. People using an LOD of 2 would probably also be using a low draw distance.

The problem I have is that I'm selling this item. If it was for personal use only it wouldn't matter so much.

Thank you for responding.

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My only comment -- well maybe two, maybe three  :D is that I personally don't know anyone who hasn't set their LOD up to 4. I mean designers have been giving out those "how to make sculpts look good cards" for many many years. YOU could include one with your build if you want.

When I test on ADITI I plunk down my building at one end of the sandbox and see how it looks at the other end of the sandbox. Honestly I don't think anything needs to look wonderful at more than a sim away. If you turn the lowest upload  setting to 0 your build "may" disappear completely which is what they all do on the Linden Realms. Then you skip any "ugly" look.

And so far as details go, keep in mind that in the real world you cannot see the cracks in the mortar from a block away *wink*.

If you have your builds out where people can see them, I can't see that either method of building would be a problem. If folks buy without seeing in world (and yes, I know a lot do) then they have only themselves to blame if they are unhappy. "I" always go check things out up close an personal on any buy over 10 linden if I can. That's me though.  If the LI is too high, it is unlikely I would buy the item for personal use. I usually live on a small lot so "prims" are at a premium. So in some ways it depends on your customer base.

My biggest seller is a warehouse skybox (hence no big worries about long distance viewing but it DOES hold up as I tested). It is 32 x 64 with tons of details and comes in at 24 LI. I doubt I would be selling them if they came in at 95  or more.

I build at LOD 4. I do not test at 2. I am a bad girl. Still, I have never had a complaint.

I do think adding a "how to change your LOD settings" might be a good idea. Note that it is VERY easy to do in Firestorm (on the quick preferenes panel) and last I heard FS had 75% of the viewer pie. Not sure if that is correct, but there are a LOT of folks on Firestorm and will be more with the new codes and demise of Phoenix.

 

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I try to build my models so that they will be acceptable with a RenderVolumeLODFactor of 1.125. Which is the setting you'll get on Low+ to  High+ graphics setting. It's only on Low set lower, and only on Ultra it's set higher by default. So It's usually the most common setting for new people who join Second Life. 

For those who have set their LOD factor even higher, they will have an even better experience. The whole increasing of the LOD factor, which became popular due to the heavy abusing of sculpted prims, is actually a pretty bad advice to do. Most likely those who have increased that setting a lot, are also those who wonder why SL is so laggy for them. :matte-motes-wink-tongue:

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I agree, but want to add one small thing.

When I build, I do not look at the RenderVolumeLOD Factor. I do test on all default graphic settings. Low means a low LODFactor, but it also means a short draw distance. Ultra means a higher Factor, but also a higher draw distance. I do not build with settings in mind like LODFactor 1.125 and a draw distance of 512. That just doesn't make any sense to me.

People that want a draw distance longer than the defaults can always set their other graphical settings higher, like the LODFactor. They do need a fast computer of course.

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Right, I actually check with LODFactor 1.125 with a draw distance of 128.

I always have to laugh when I drive on a race track behind a 170k poly car, with a land impact of just 20, but I only see a driver floating inbetween a bunch of triangles, until I get close enough, and a car pops out of nothing. :matte-motes-smile:

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And that will keep you from buying that car..hey maybe that whole capitalist free market and competition thing kind of works after all!

I'm afraid though that the number of laughs is matched by the number of "wow that has to be the best looking car in SL" 's. Maybe it's dirty race tactics, making sure you have a great computer so you see things the way they should without lag, then distract half the other people with laughter and lag the other half into driving off the track.

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Chic Aeon wrote:

My only comment -- well maybe two, maybe three 
:D
is that I personally don't know anyone who hasn't set their LOD up to 4. I mean designers have been giving out those "how to make sculpts look good cards" for many many years. YOU could include one with your build if you want.

 

hehe, you talk like a merchant - my language :P 

I also don't normally test at low LOD factors, until recently - my appdata became corrupted and I was pushed back to default settings without realising it, and suddenly my wonderful hard work looked crap. When I realised why I got to thinking about people who use default settings and how they saw my creations. Although I do sell these walls inworld so some people are seeing them first. 

I'm going to stick to low LI and just neaten up the worst of the medium LODs, and I'll include that notecard on sculpties at a distance in my package.... and not worry about it anymore.

See, you can't please everyone so you got to please yourself.

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I would also usually aim for acceptable appearance at all distances for rvlf = 1.125 and dd = 128. Of course, what that requires is totally dependent on the object size. Here are some pictures illustrating the situation for ultra settings (top 6) and high settings (bottom 6). The six panels are for a cube-shaped object with dimensions from 1m increasing by powers of two (1,2,4,8,16,32). It's at the corner of four regions shown by the four squares. The dotted circle is the draw distance. If your camera is outside this (white area), you don;t see the object at all. Otherwise, the coloured circles show which LOD you see when the camera is in them; red=high LOD, orange=medium LOD, yellow= low LOD and cyan=lowest LOD.

lodrings.png

The important thing to notice is that for larger objects the lower LODs may never be seen at all, but for small objects it is often seen for both these settings. This effect is what underlies the decreasing effect of lowest LOD (etc) on LI as the size increases. The download weight calculation implicitly assumes renderVolumeLODFactor = 1.0 and draw distance = 181m. (that's the radius of a circle that encircles a whole region).

PS. I made a program to generate these for any parameters ... ask if you want to see others.

ETA: altered pictures so that area of object invisibility is always white, and text accordingly.

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An interesting discussion.


I am not sure there is a "correct" answer here.    SL looks really awful (AWFUL) at low graphics settings - LOL. I had to log in on my six year old notebook when my computer was in the shop one day. It will only run on Singularity at low. It was painful, laggy and ugly. So folks that use those low settings are most likely used to that -- their norm.

It seems unfair to me to penalize the folks that have made investments in the SL lifestyle (faster connections, better computers and even better graphics cards), so I won't be building high land impact items so that the new folks can see the world better :D.  

The bigger issue and philosophical point MAY be that we don't really need to live in an all mesh world. Some things really don't work well in mess (big often being one of them). I made some low rolling hills to be used on pads in the air to simulate ground. They look pretty good (not wonderful as they have sharper curves than I would have preferred but nice).

I had to make the decision you are making then, but even so the land impact is higher than is practical. 32 for a 32 meters and 69 for 64 meter squares. They are low poly and I used all the tricks I learned from this board to get them even that low. I made a "hill" the other day and it had the same issues. Got it down to 7 by taking off the back section which won't be seen unless you cam where you shouldn't. Not sure yet, if I will ever upload it to Agni.

There are some things that while we can make them aren't all that practical in SL. Mesh is great for furniture, hair, clothes  etc but when you get to the big buildings you run into issues even if you are a low poly modeler. I have decided that for ME, the answer can be Primesh (what I call it) -- a blending of both mesh and prims. That often does the trick.

I do use the rolling hills and they have come in very handy at LEA7 and definitely make the landscapes in the sky seem more real. There is a prim cost to be paid of course. So we each have to decide as designers and consumers, what works for us. I can't see any perfect solution.

 

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I'm afraid though that the number of laughs is matched by the number of "wow that has to be the best looking car in SL" 's. Maybe it's dirty race tactics, making sure you have a great computer so you see things the way they should without lag, then distract half the other people with laughter and lag the other half into driving off the track.

 that statement brought a big grin into my face, lol

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To whom you want to sell your creations in the future, if we all would go that route? I mean, it's no wonder that newbie's turn on a dime and leave SL after 5 minutes, if everything just looks like crap for them with default settings. They won't even stay long enough to get deeper into the Debug Settings.

Also, we're living on a region which is surrounded  by other regions. If our neighbors would only have these poor LOD meshes, we will look at this crappy builds most of the time. It's even worst for people who are living on parcels, next to each other.

Also, if we make everything so low in LI that you can put everything you want onto a 512 parcel, it's no wonder that nobody needs more land anymore, to place more objects. The grids region count will go down even further. Not so bad for us, but bad for the Lab, which might become bad for us at some point in the future, too.

I also can easily crank up my LODFactor and still have good performance on my machine, but I don't want to. I want to make usage of the system how it is designed, which is reducing the geometry in a distance. And by reducing I don't mean watching at only HIgh LODs or at nothing at all.

But that's just me perhaps. I also don't want to tell anybody what to do, or what not. Everybody have to do it their own way to be happy. It's just the way how I see it, since you asked if other creators would care.

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arton Rotaru wrote:

But that's just me perhaps. I also don't want to tell anybody what to do, or what not. Everybody have to do it their own way to be happy. It's just the way how I see it, since you asked if other creators would care.

And I do care what other creators and residents think, which is why I'm here asking. 

And the strong message I get from everyone is to keep the Land Impact as low as possible so it isn't a drain on resources. To do this I will have to accept that the building will lose it's shape very quickly for those using lower settings. It isn't so bad when LODFactor and draw distance are both low because the building disappears or fades out before it shows the detail of the medium LOD.

I just need to make sure that when I build my medium LODs that they look decent enough while keeping them very basic, and have a texture to match the original very closely in pattern, size etc. And I think I can set the low and lowest LODs to zero. This should give me a wall that is large, highly detailed with windows, doors and broken bricks at a land impact of 1.

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I read your message again and I don't think you are agreeing with me. So spell out a little what you think I should do. Do you think I should be making my medium LODs a bit more detailed and push them up to a higher LI so that newbies and people using lower settings can see them better?

There is a big part of me that wants to go this way.

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It all depends on the size of your wall. Its radius is defined as half the square root of the sum of the squares of its three dimensions (sqrt(x*x + y*y + z*z)/2). If this is more than 5.43m, the lowest LOD will not have any efect on the LI; so you can use the low LOD again in that slot. If it's bigger than 10.86m, then the low LOD will have no effect; so you can use the medium LOD for the three lowest slots. These will only be seen by people using higher than standard draw distances. 

If you need to simplify the medium or low LODs to get a reasonable LI, you can use a simple box with pictures of the high LOD model on alpha textures on the sides, so that it still looks as if the detail was there. You will have to use a hidden triangle to hide the unused material(s) at each LOD. This will work much better when normal maps are available to mimic lighting effects.

 

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Rya Nitely wrote:

I read your message again and I don't think you are agreeing with me. So spell out a little what you think I should do. Do you think I should be making my medium LODs a bit more detailed and push them up to a higher LI so that newbies and people using lower settings can see them better?

There is a big part of me that wants to go this way.

Yeah, I'm sorry about my bad english. My statements might sound harsher than I want them to be, due to the lack of knowledge how to phrase things more polite in english, my bad.

Like what Drongle pointed out, it depends always on the size of the object, and for what use case it's made. The thing is, we have 4 levels of detail which we can use in SL. Those are meant to be to reduce the geometry of an object in the distance without going the object to be missing entirely from the scene. They are not meant to be to reduce the land impact on items significantly by setting the lower LODs to just a single triangle. You will never see such poor LOD models in other games. Of course, they only have to worry about the over all poly budget, and they don't have to deal with this land impact thing, where people have to pay real money for each prim in SL. So we have to make more compromises than other artists will have to. That's for sure.

Don't get me wrong, I'm all for a LI as low as possible, of course. I abused sculpted prims a lot myself, back in the days.

Nowadays, I take a few more prims on some meshes to keep their look over the whole LOD range. There are objects where I was able to safe a huge amount of LI, compared to prims/sculpts, and there are other items where I have to spent a bit more LI than with prims. Bottom line is, it may equal out, with a tendency to a lower over all count, than with just prims. I actually have way more stuff rezzed on our homestead, and have still more available prims left, than it was before mesh arrived.

So for your wall, depending on how big it is. I would also reduce the Medium LOD significantly, but not so much that it will break apart in an ugly way. For the Low and lowest LOD a simple box like shape, maybe just 2 planes will be enough to keep it as a wall, from the distance. This might raise the LI a bit. But it shouldn't raise it to much in the end. And it's visual appearence in the whole scene might be worth the slightly higher LI.

But as I said already, It's up to anybody, what they want to achieve with their creations. I only can't stand those who upload really high poly models (e.g. 170000 tris), like some car makers do, set all lower LODs to a few triangles, tell people they will have to increase their LOD setting, and then advertising it with it's super low land impact and awsome details.

What you have then is, high poly content, and a viewer which renders only Hi LODs all over the place most of the time. Which isn't really the way to counterfight bad performance in SL IMHO.

Here's a mesh model I made lately (just to show some pics). It's Land impact is 43. That might sound high at first, but it's pretty detailed, and has a couple of detailed itmes linked inside of it, too. I used the technique which Drongle describes above, where I have put all the beams, and planks on a single 256x256 alpha texture on the Low and lowest LOD. For a closer look, and what's all inside the hut, there's a video of it on youtube.

[aR]-Lifeguard-Tower-Highest-LOD.jpg

[aR]-Lifeguard-Tower-Lowest-LOD.jpg

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Very well done! You have lots of detail inside and out. And as you said, it keeps the shape nicely from a distance :)

I am using Drongle's suggestions. Some very useful points there that I didn't know before. Like using the same LODs in the lower levels if your object is big enough. And the formula to calculate it. My wall is roughly 7.5 meters - 12, 1.2, 8.5. I also took a picture of the high LOD build, made the windows and doors transparent, and used this as Drongle described on all 3 lower levels. I gave the box a bit of shape too with 4 more vertices, and I could add more. This is working very well. LI is still only 1.

I have something that works now. Thanks everyone.

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arton Rotaru wrote:

You will never see such poor LOD models in other games. Of course, they only have to worry about the over all poly budget, and they don't have to deal with this land impact thing, where people have to pay real money for each prim in SL. So we have to make more compromises than other artists will have to. That's for sure.


Overall polycount and LI are directly connected so game devs face the same design issues we face here. I wonder if people spending RL money on a game would ever accept poor LoD models like we see in SL, I don't think so.

There are some big differences between games and SL though, for example, in games the engine can load and unload scenes, when you enter a next level, or when you go through a door. In games you can't rotate your camera behind objects, in games you can't walk or fly everywhere.

Another big difference is people in SL often go to a place and stay there, a club, their house, a store. I can understand the trade off between LoD models and LI in those cases. Why would a landowner sacrifice valuable LI for visibility from the next plot where his/her visitors will never go? There are other situations though, where an entire sim is used, a racetrack, a city, a mall (do they still exist? :) ). In situations like that I would never let LI overshadow the looks from half a sim or a full sim away. All in all, it really depends on the situation on how LoD models are used. This of course is a big problem with the biggest difference between games and SL: unless the object is purpose built, the creator will never know how and where it will be used. So I think it's good to have some creators who build very low LI items and others making similair items that keep their shape very well. There is no good or bad design philosophy here, well except when builders know their model will break up too soon for its purpose (like the car mentioned earlier) then advice to crank up some debug setting. I've done this in the past myself with some sculpties, but I wouldn't do that anymore since we have full control over our LoD models.

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Kwakkelde Kwak wrote:


arton Rotaru wrote:

You will never see such poor LOD models in other games. Of course, they only have to worry about the over all poly budget, and they don't have to deal with this land impact thing, where people have to pay real money for each prim in SL. So we have to make more compromises than other artists will have to. That's for sure.


Overall polycount and LI are directly connected so game devs face the same design issues we face here. I wonder if people spending RL money on a game would ever accept poor LoD models like we see in SL, I don't think so.



Regarding scene performance, they face the same issues, sure. But that wasn't my point. Let's say a game contains 5 million polygons. You pay like 50 euros for it. Another game contains 10 million polygons, you also pay like 50 euros for it. If you want to place 5 million polygons in Second Life, you have to rent a homestead region, 125 US$. But if you want to place 10 million polygons in SL, you have to rent another homestead and pay twice as much.

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These statements confuse me a bit: 

Maybe i am understanding you wrong here, if so : my apologies - but this here has me 'confuzzled':

Let's say a game contains 5 million polygons. You pay like 50 euros for it. Another game contains 10 million polygons, you also pay like 50 euros for it.

- the concept of counting a game and its value or price on the amount of possibly appearing polygons throughout all
  levels and game- /render -time being spend on it  is new to me..

- normally you count what has to be drawn within a certain frame or a scene /level.
- it don't understand the thinking concept here, to compare values and price with the amount of polygons you possibly
  will have to render during all your sessions in the game.

- and for the 'value' of a game i normally consider things like : available ame time, replay value, mutliplayer or single
  player,  type of game / genre, and of course : graphics and artstyle (and here i don't really count the poylgons in a scene
  rather the all over optical style and quality as tessellation, mapping techniques and of course the artwork / style itself.),
  and so on.

If you want to place 5 million polygons in Second Life, you have to rent a homestead region, 125 US$. But if you want to place 10 million polygons in SL, you have to rent another homestead and pay twice as much.

- i wouldn't really see that as in 'polygons' either. 
- you rather have to see it as : how much place will it take on a server, how much calculations will it cost the server to
  handle those objects. As just as we had it with 'prims' and primcount before, that is the factor being taken into account
  regarding: when exactly is a simulator 'full'.
- And i personally would not compare secondlife with the cost of a game.

  My points for the 'why':

- It does not have a limited playtime. Like a regular game has. (20-40 hours average to play it through for your 
 
mentioned ca. 50 dollars)
- Compared to MMOs: when you watch what some people spend in terms of money on MMOs over the years including
  
monthly payments, and items being bought, that isn't little as well.
- In secondlife you don't only 'buy' a game, you rent virtual land, which you can also rent out to others and actually make
  money out of it. You rent the space on the server. (which is for instance, different from joining an MMO server as Player)
- The serverspace is reserved for you, and you can set it up for your likes, rent it out, etc. That is quite different from
   joining instances in MMOs or having your little personal home there.
- you have a full social network along that exceeds the regular Game or MMO forums, and the marketplace also exceeds
  the common game 'auctions' for trading items.

- I could go on.. but i guess you know what i mean by now.

It may appear expensive but when you have a look at what dedicated servers cost already for leasing:
just an example: 

type/status/ GB/ Space/ Installing cost/ monthly fee:

Dual Xeon E5680 3.33Ghz
Unmetered 32GB 1000GB $25.00 $795.00  
Dual E5 2690 2.9Ghz
Unmetered 32GB 1000GB $25.00 $820.00

And then have a look at how many regions / simulators can run on each core:

Class 5 (Quad Core CPU): 4 Full Regions per server (1 per core), 16 Homestead Regions per server (4 per core)

Class 7 (8 Core CPU):  8 Full Regions per server (1 per core), 32 Homestead Regions per server (4 per core)

common is around 8 Regions (if these values didn't change by now).

Let's say we divide the fasted server cost through 8 regions / 8 users renting a part of it. Then we get to around 100 dollar per month. And with a dedicated server we would have to do all the service and maintenance ourself, so this isn't even inlcuded regarding the cost it has to run things. SL has to buy servers as hardware and maintain those. 
So the prices line up prett much with what you would get when leasing a part of a server somewhere else.

They might be a bit on top of it, when the server hardware is older etc. But as mentioned above it includes the ingame and out of game services as well, plus they need to earn some income too, and pay the staff.

And as Kwakk already said, and i follow up on this by adding these points, SL isn't really a 'game'.

I hope you don't feel offended, i just couldn't really get a hold of your thinking concept here. :)

 

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No no no, I don't count the value of games in polygons. This was just a very simplyfied example to draw a picture. Since this topic is about Land Impact and the visual appearence of models, I just meant that you can make a game and put as many models in it as you want, and "only" have to make sure that each scene will work perfectly. It doesen't matter how many models you sell to your customers within the game, the price will be the same, more or less.

In Second Life we have to compete in a market, where we have to pay directly for the number of models we want to have rezzed permanently. So there is a factor where we have to make compromises between a model looks perfectly good over all LODs, and how much it will cost the customer to have it rezzed in-world. Of course, these are not all aspects of which have value in Second Life or games.

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