LOD Levels for walls and floors

[Ciaran Laval]

One of these days I'll actually build a mesh structure without coming back here to ask questions. Today it's LOD levels bugging me. With walls and floors, especially if yu use planes, how do you go about setting them?

Using the defaults in the uploader, they disappear much sooner than an inworld prim will. Setting LOD to the highest LOD level on all four levels doesn't hit land impact, but it doesn't feel right. Do you use highest LOD for the highest two and set the bottom two low, set just the lowest level low, or not worry about it much?

Being as they are likely to be planes or cubes, there's not much to reduce in terms of triangles.

I know you can take a different approach for internal walls and floors as opposed to external ones, but external ones are often part of a mesh that is also going to be an internal wall too.

[Chic Aeon]

Lots of very smart people here that will have some good info for you.

I can tell you that building the house in "modules" will help with your land impact and is often the best route. 

That you can make and upload SIMPLE CUSTOM LODs for your walls if needed.

Best to keep exterior and interior walls separate if you can. If you are making ambient maps you can have them in place for the shadows, just don't join them before export. That way you can upload them separately if needed.

I don't particularly like making houses, but I do make PARTS for house *wink* and made a great warehouse that has turned out to be very popular.

And yes, using the highest LODS the uploader gives you is probably a very bad idea .  The best thing to do is experiment on an ADITI sandbox and see if you can get the distance look that you are after without wasting server resources by overdoing the LOD settings. Make your exteriors hold their shape as needed. Interior walls won't need as high of settings.

I am not really sure about using planes for houses, I have always used cubes so my point of view may not be relevant to your issues . 

[Codewarrior Congrejo]

if it's simple single polygon planes or boxes i prefer to simply load the same Model into the highest 2 LODs. This ensures it to look exactly the same for the first 2 viewing distances. You can also think about loading it into all 4 levels. in case it's really just a one-polygon plane that's the best way of keeping it visually stable, if it needs to be seen from far away.

I really don't bother about the lowest 2 in that certain case because for a simple one polygon plane it doesn't matter anymore when you are already 100 meters away. But again it depends where that plane or box is, and if i need to preserve it's visability on further distance or not.

If its box-shapes being covered by walls etc then i mostly remove ther covered sides.

For buildings you can even contemplate to make LODs where the inner walls /floors will be removed completely more and more towards the 2 lowest levels. (unless its a very open building of course where would want to preserve their visability somehow)

That being said, i can only repeat it really depends where and what those simple objects represent and how much need of keepig them being visible from further distances is.

 The serverside offered LOD algorythms are barely a good choice, i only use them on rare occasions. Especially choosing the highest ones from those - as soon as the model becomes a bit more complicated it will hit the LI values.
Plus as you already noticed you don't really have any 'control' on how they will break your model down, and ugly texture stretches or even folding and collapsing of the mesh's shape are the results.

 

[Dora Gustafson]

When you go experimenting in ADITI keep in mind that your viewer's graphic settings make a lot of difference to what you see.
I have experienced that some specific objects can be seen in full definition on a viewer with graphics set just below Ultra, from any distance
The same objects do not render fully on a viewer set to Mid from a distance of 25 meters

The objects are mesh walls 12 by 4 meters and some 8 by 8 meters

:smileysurprised::smileyvery-happy:

[Kwakkelde Kwak]

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Ciaran Laval wrote:

 

Setting LOD to the highest LOD level on all four levels doesn't hit land impact,

[...]

Being as they are likely to be planes or cubes, there's not much to reduce in terms of triangles.

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You just gave the answer yourself.

If your highest LoD model is very simple to begin with, there's nothing to reduce and you do not have to reduce. You can use the same model four times. What you can reduce over distance, so per LoD, is detail such as window frames or cornices, interior parts etc, anything that you do not have to see from far away.

I usually split up exterior, interior, windows and if present cornices. The exterior is usually big so either the very highest or  the highest two LoDs will be enough. Setting the unused LoDs is useless since you'll never see them (you might if you crank up the draw distance to more than 256). I think the uploader doesn't count the lower LoDs in big objects for this very reason.

[arton Rotaru]

It depends on the draw distance in conjunction with the RenderVolumeLODFactor setting in everyone's viewer, which controls if/when someone sees the lower levels. Since I have no control over how other people have set up their viewers, I always try to keep larger main structures intact over all 4 LODs. There's nothing more disturbing than collapsing houses when zooming out. There are chances where I can remove one or the other triangle at a lower LOD, but most of the time, these things are so lowpoly right from the start, that it doesn't matter much anyway. So yeah, I load the Hi LOD in all 4 slots in such cases.

I also try to build everything as lowpoly and efficient as possible, but I don't go crazy about it. If it's super efficient, but doesen't look or feel good enough anymore, it won't help much also.

[Ciaran Laval]

Thanks for all the feedback guys and yes Kwakkelde I did seem to answer my own question there, although I didn't realise it until you pointed it out to me!

Lots of good information for me to chew on, thanks a lot.

[Rahkis Andel]

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Ciaran Laval wrote:

I know you can take a different approach for internal walls and floors as opposed to external ones, but external ones are often part of a mesh that is also going to be an internal wall too.

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Just to clarify, there is no building layout I can think of where the external walls must be connected to the inner ones. If you have a problem with that, post again with a screenshot of what you are trying to do and I'll show you how to make it modular.

It sounds like you know what you're doing, though.

[Kwakkelde Kwak]

I can, lots of modern houses have those kinds of walls, floors and ceilings.

Example

Big pieces of glass might also be an issue if the interior disappears.

[Rahkis Andel]

That's not impossible, just challenging. The glass would be an issue, but then again, a little creativity could make that work too.

Granted, I'm all talk here. I'm not willing to go through the trouble of attempting to do this to illustrate a point. Take that as a concession if you like.

[Kwakkelde Kwak]

Actually those buildings should be the easiest and low LI ones around. All shapes are very primitive.

Anyway, if it can be built in RL, it can certainly be built in virtual space. The problem with the windows is, with small ones you can make them opaque at a certain LoD. With very large glass surfaces (biodomes?) that could look very distactive.

[Ciaran Laval]

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Rahkis Andel wrote:

Just to clarify, there is no building layout I can think of where the external walls must be connected to the inner ones. If you have a problem with that, post again with a screenshot of what you are trying to do and I'll show you how to make it modular.

It sounds like you know what you're doing, though.

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Ugh I hate doing this but all I'm trying to do right now is build a mesh version of this:

https://marketplace.secondlife.com/p/5-Prim-Tudor-Style-Store-V2-Small-Tudor-Style-building-ideal-for-a-market-in-a-fantasy-or-roleplaying-location/420634

Now as the ground floor is open and therefore the internal and external walls are in the same linkset, it's tricky to make the internal and external different without adding additional costs. I want the interior to be viewable, that's part of the point of that design.

Upstairs isn't so important.

[Rahkis Andel]

Well, for one, I wouldn't worry too much about this one. It doesn't require enough tris to worry much about different LODs.

Edit: Haha, I said "for one", but I really don't have anything else to say, there. I don't think you need to worry about how that is connected. it's just two stacked cuboids and a triangular roof.

[Rahkis Andel]

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Kwakkelde Kwak wrote:

Actually those buildings should be the easiest and low LI ones around. All shapes are very primitive.

Anyway, if it can be built in RL, it can certainly be built in virtual space. The problem with the windows is, with small ones you can make them opaque at a certain LoD. With very large glass surfaces (biodomes?) that could look very distactive.

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I'm half asleep, sorry. What are we talking about again?

[Kwakkelde Kwak]

Erm, first comment is about modern buildings made out of cubes. They are so low poly I wouldn't worry about anything.

The second comment is about windows. If you have a big exterior wall with small windows, you can seperate walls and windows and make the windows go opaque from a certain distance. Since the windows are small, both visually and as an object, the next LoD will show earlier than the next LoD of the interior. So if you make the windows opaque at one of the lower LoDs, you won't notice the interior disappearing. When you have very large windows, they might look funny when they switch to opaque.

[Ciaran Laval]

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Rahkis Andel wrote:

Well, for one, I wouldn't worry too much about this one. It doesn't require enough tris to worry much about different LODs.

Edit: Haha, I said "for one", but I really don't have anything else to say, there. I don't think you need to worry about how that is connected. it's just two stacked cuboids and a triangular roof.

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Yup it's a very basic build but rebuilding it with Mesh serves two purposes. One is that I want to change my buildings to be pathfinding friendly, which means changing the way linksets are built. Whilst doing that I thought it would be a good idea  to do that whilst making them Mesh.

Although very basic you get into issues such as physics shapes, whether you need them on say the roof, for example, do I really need the roof to have a physics shape.

Then you get into how using a cube seems like a great idea, as it means not having to piddle around with texture repeats on wall edges, until you realise a full cube won't allow people to rez anything inside them.

From there you can get into adding bevelling and giving it a bit more oomph, which is what Mesh brings us.

 

 

 

[Ciaran Laval]

Ok yes I see where you're coming from with windows, that makes perfect sense.

[Rahkis Andel]

Just to clarify, your question was answered, yes?

You can just use the highest LOD for all levels for something like this. If you wanted to give it a lot more detail and make the upper floor walkable, then you'd want to start thinking about this again.

@Kwakkelde Kwak: Your patience is admirable. I seriously wasn't expecting for you to actually explain that. I was only pulling your leg, my friend.

[Kwakkelde Kwak]

I think it's good practice to make windows that way, so I thought I'd explain.

What else can I do but answer questions on the SL forums on a sunday? You're not suggesting I should go out and enjoy the weather do you?

[Ciaran Laval]

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Rahkis Andel wrote:

Just to clarify, your question was answered, yes?

 

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In terms of not worrying so much about LOD levels with such basic shapes, then yes the question is answered.

[Ciaran Laval]

This thread has been very productive for me and I'm grateful for the answers here. I know that my questions are extremely basic in terms of modelling but that's where I am with the modelling, thanks to the answers here I can move on.