Lowwering land impact - please help!

[LiamZander]

Hi there!

I've been into blender for quite a while, but because it's not easy to find decent low poly modeling tutorials, I'm still struggling finding my way into lowwering prim count in my models, and I would be really grateful for any help.

In my projects I have been trying making as simple meshes as I can with multiple faces, but prim count is never satisfying compared to what I can find on the market and stuff people make without affecting lod in any way.

For example here: 

 

That model is only 2 LI, however it cointains crazy number of loops and doesn't miss any faces on the back, yet LOD is great even on 2.0 settings in viewer. 

If I attempted making something like that it would be way more LI than that...

I'm using LOD generator in viewer, I don't make my own LOD maps. I'm not sure if that's the reason, because while zooming out I didn't see LOD changing topology.

Another example is making a chain. For exmaple trying to make chain necklace this way: 

 

...ended up for me with chain itself being 50 LI  and I used torus 6x6, and even if I've made all the LOD 0 it still was a crazy number of prims.  And I've seen people makign necklaces with exactly the same geometry and it was LI prims.

 

Are there any modeling techniques that help reduce consumption of resources? 

If anyone could share it with me or point me to any tutorials where I could look into it I would be really grateful...I'm not sure what I'm doing wrongg, 

Liam

[ChinRey]

There are so many tips and tricks I hardly know where to start.

You definitely need to do all the LOD models manually though. With the auto-generated ones you can get high LOD (as you say you did) or low LI but hardly ever both at the same time.

And for intricate curved items like this smooth normals are essential. With them you can reduce the number of triabngles to a fraction of the number you'd need to get the same look without. In fact, I'm not sure if you can get as smooth looking curves as the one in the picutre you showed without them not matter how many tris you put into the mesh.

Then it's all a matter of understanding what LI and LOD is. How the different weights are calculated, how the switch points are calculated and so on and so on. It's not rocket science but it does take quite a bit of studying and/or trial and error to learn how to make efficient mesh.

You don't mention which weight it is that decides the LI. The number of triangles and vertices affect the download weight. Doesn't help much to reduce that if the server weight or the physics weight is too high. Well, of course all weight reduction helps a little bit to reduce the risk of lag but when it comes to LI, only the highest of the three counts.

Finally, figure out what you need and what you don't need to include int he mesh. And figure that out independently for each of the five models (Five? yes, four visual models and one physics model). Every little unneccessary detail you can eliminate (or replace with some clever texturing) helps reduce the LI just a little bit.

 

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(Edits: just correcting typos)

[LiamZander]

Thanks for your reply, ChinRey.

I guess I will have to get over it and start making LOD manually, because it helps drastically. 

Thanks for tips!

 

Liam

[Aquila Kytori]

Hi

Using the same starting torus as in your example I made an Avatar size necklace.

In example 1: the chain links are unwrapped in Blender and uploaded using the default LOD settings and a cube for physics. LI = 23

In example 2: same chain but this time setting the Lowest LOD to minimum. LI =1

I have my RenderVolumeLOD factor set at 1.25 and because the links are so small compared to the size or the mesh I was unable to notice a difference between the 2 versions as i zoomed out.

 

In my third example its exactly the same chain necklace but this time the links are not UV unwrapped, its uploaded using the default settings and a cube for physics. LI = 200

 

This is a bug of sorts and only effects certain types of mesh like your chain links AND if the mesh has not been UV unwrapped before uploading. See this earlier thread ..   http://community.secondlife.com/t5/Mesh/LI-count-something-not-right/m-p/2254573#M23880

 

Edited : I hope the imges stay loaded this time ........ I think i have reached the limit of uploaded image memory so now have to delete old ones to make way for new ones and because I have no idea of the sizes of the image files sometimes I have to delete 4 or 5 to old ones before i can upload a new one

edit, edit 1 last try ..........

[Aquila Kytori]

This is just a test .

The second image in my previous post was showing ok in the preview window and in the finished post but later was disappearing.

And the second image was only 154kb .png and I am sure i deleted way more than that from "My Images"

Just noticed i could start a new Album (The old one says it contains 271)

So with the problematic image in a  New Album I try to get it to stick here .......

and again ..........

[LiamZander]

Thanks for help!

I am experimenting a little with it, and it seems like that "glitch" works.... that might be sort of helpful  

 

[ChinRey]

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LiamZander wrote:

I guess I will have to get over it and start making LOD manually, because it helps drastically.

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I'm afraid so, Liam. The basic idea behind the LOD models to simplify the visual models of objects viewed at a distance since the finer details will be too small to see anyway. Obviously, the more you simplify, the lower the land impact gets but it's important to remove only the details you don't need and keep the ones you need.

The uploader tries to calcualte what to keep and what to omit automatically, but it does a horrendously poor job, wasting LI on unnecessary tris and deleting crucial ones. Even LL admits this. But they claim they bought the best algorhitm on the market for the job and that nobody has figured out a better way yet. Making really efficient mesh takes a lot of experience (and a bit of studying helps too) but even a beginner can easily do a better job than the uploader. (Btw, the uploader does an even worse job creating physics models but making those well does require a bit of knowledge and experience so a beginner may still be better off using autogenerated ones for that.)

 

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Aquila Kytori wrote:

This is a bug of sorts and only effects certain types of mesh like your chain links AND if the mesh has not been UV unwrapped before uploading. See this earlier thread ..  

http://community.secondlife.com/t5/Mesh/LI-count-something-not-right/m-p/2254573#M23880

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That's a new one to me - I better keep an eye out for that bug. Thanks! :-)