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Devriv

LODs affecting physics complexity?!

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Hello Everyone.  I have a small shelter with triangle/plane physics (no analyze).  When I upload it using my own LOD models, rez it, and check the physics under render metadata, the physics model is yellowish in colour.

The same model, with the same no analyze plane physics model, uploaded without its lower LODs, using the uploader’s own lower LOD defaults, displays the physics in Blue!

I don’t know why.  I don’t believe it’s relevant but my LODs models have all the exact same dimensions, and that’s the only possible factor that occurred to me was causing this difference in the display of physics complexity.

I've left both models here in this sandbox:  secondlife://Aditi/secondlife/Mesh%20Sandbox%203/13/8/23

PhysicsDemo.png

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I always wondered why some of my physics shapes are grey-ish colored, when they shoud be blue. That might be an explanation for that then. Which leaves the question of the why still unanswered though.

 

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 I (well Lani) went over and looked as she was close by. I have no answer either but I can say that ALL of my physics models (at least the houses and things that I look at) have been bright blue (CUBE PHYSICS - ANALYZED) until I did some planes physics recently and they were bright yellow. I have only seen that odd grey beige color on some items from other creators when I was blogging. Not sure WHY it turned on physics models but I did see that then. 

I almost never make my own LODS so the only difference for me is that cube physics models are blue and planes physics are yellow. I have never seen (when I have bothered to look) a gray-beige physics model on my stuff.

 

I am guessing ChinRey knows the answer and I will be interested to hear it. She mentioned something about the different colors of physics and at that time I had only seen blue for my stuff LOL. So a surprise for me. 

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The physics shapes are indeed color coded, from blue (good) to red (bad) with green, yellow, orange inbetween. (it's colored like weights on a skinned mesh)

But that still doesn't explain why it would change with the different LODs.

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Thank you for the replies Arton and Chic.  I even tried box (analyze) physics for it a few days ago, and still couldn’t get it to change to blue.  Unfortunately, it didn’t occur to me then to do the same experiment.

Regarding the colours, yes it is more grayish-beige than yellow.  I haven’t been able to find the wiki page that lists and explains the colours.  

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29 minutes ago, Devriv said:

I haven’t been able to find the wiki page that lists and explains the colours.  

I dunno if this is actually documented at all in the wiki. You would have to be at the office hour meetings at the time these features were implemented, when Lindens talk about such stuff.
I found a transscript of an office hour, where Nyx is talking about a tool to visualize render cost by color-coding content. And a couple of lines further down, Falcon Linden mentions, that he used it to color the physics shapes display.

Start reading at:

Quote

11:06] Nyx Linden: I created a new tool to visualize render cost by color-coding content

http://wiki.secondlife.com/wiki/Mesh/Archive/2011-03-28

Edited by arton Rotaru
Forgot to paste the link ^_^
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Thank you Arton. Hopefully someone will shortly explain the meaning of this gray colour too, which is probably closer to the yellow than to the other colours mentioned.

Edited by Devriv

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9 hours ago, Devriv said:

I don’t believe it’s relevant but my LODs models have all the exact same dimensions, and that’s the only possible factor that occurred to me was causing this difference in the display of physics complexity.

I assume the actual physics weight is the same and only the color the model is displayed with changes, right?

The color coding of the physics model dispaly does not depend only on its complexity. There must be some other factor(s) too since fairly complex models may well show up in blue whiole relatively simple ones can sometimes be yellow. It seems the viewer has some crude algorithm to guesstimate what a reasonable physics weight would be based on the visual model and it's quite possible the LoD models will affect that calculation.

I've never seen that grayish color but I would guess it's what you get rigth on the border between blue and yellow.

I any case, my best advice is something a Linden once told me: Do not trust the phsyics model display in the viewer.

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 I don't think its   " LODs affecting physics complexity?! "  but more like Lod complexity effecting Physics colour.

I did some test uploads using a 10 x 10 meter plane that was subdevided into 2048 triangles for the High Lod, and a 2 triangle plane for Physics.
 

5989e8fcc16de_HighLod.png.ab1b10f9d89f3a063eed03e989e9e5b4.png

Plane A is an upload using the 2 tri Physics plane in the High LOD slot and in the physics slot, not Analyzed.   (see image below.)

Plane B is the 2048 tri plane as High LOD, default Generated for the lower LOD slots and the the 2 tri plane as Physics model.

Plane C is the 2048 tri plane as High and Medium LODs, used Generated for other 2 slots. 2 tri plane for Physics.

Plane D is 2048 tri in top 3 LOD slots and Lowest is Generated. 2 tri plane as Physics.

Plane E has 2048 tri plane in all LOD slots and 2 tri plane for Physics.

5989e5c4a4b2d_TestplanesPhys.thumb.png.659ff7c5e7bb1b32cd1935bdb88ede7a.png

After rezzing and setting to prim I made a copy of each and resized the copies to 2 x 2 meters.

It seemed to me the the Display weight had some connection with the Physics colour.

With the edit panel open so that I could watch the Dispaly weight change, I resized the 10x10 plane C untill its Display weight equalled the dispaly weight of plane B.
The new physics colour matched the physics colour of plane B.

I Did the same for plane D and again the physics colour matched.

5989e5d0d3faa_ColourDisplayweight.png.88cbe3d0e61ff1bea4635aad78000afc.png

The LOD complexity, density and size of the mesh  effects the colour of the Physics but not the actual Physics weight. So as long as the Physics cost seems correct don't worry to much about the colour. :)

 

Edited by Aquila Kytori
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So Falcon just added the color code tool as is (Render Complexity), and did not adapt it to the complexity of the physics shapes. :S That's meh!

Thanks Aquila, one more mystery uncovered.

Edited by arton Rotaru

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1 hour ago, arton Rotaru said:

So Falcon just added the color code tool as is (Render Complexity), and did not adapt it to the complexity of the physics shapes. :S That's meh!

The Physics colour code does work for Physics complexity as it always has but it also has a little Lod complexity in the mix as well :)

This time I Uploaded  Mesh A as the High Lod mesh and used mesh A, B or C for the Physics mesh.

There is a 2 meter gap between front and back planes.

598a06910d598_Frontfacetris.png.1690fd8568c6fcfcf999ae500df3202e.png

The colour does change as expected for Physics mesh complexity and size.

598a06a0ea0e6_Parraleleplanes.Physics.thumb.png.7d449b46ff9922b5502d2e112f902d48.png

 

One thing I wasn't expecting was when changed to Prim the B anc C mesh act as Planes type Physics, ie you can walk between the front and back planes, but they look like they are still convex hull. ?

 

 

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44 minutes ago, Aquila Kytori said:

The Physics colour code does work for Physics complexity as it always has but it also has a little Lod complexity in the mix as well :)

Ok, that's only half meh then. :SwingingFriends:

 

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Thank you so much for the tests Aquila.  I’ll see if I can make any modifications to the lower LODs and will post here if I manage to get the blue, otherwise I’ll leave it as is.

“I assume the actual physics weight is the same and only the color the model is displayed with changes, right?”    

Thank you for the reply Rey.  I’d also say that the gray seems somewhere between blue and yellow, with yellow indicating complex, and not “bad” per se.  And yes, the physics weights remain the same; only the colours, and as Aquila has now pointed out, the display, change:

PhysicsDemo2.png

Edited by Devriv

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14 minutes ago, Devriv said:

Thank you so much for the tests Aquila.  I’ll see if I can make any modifications to the lower LODs and will post here if I manage to get the blue, otherwise I’ll leave it as is.

“I assume the actual physics weight is the same and only the color the model is displayed with changes, right?”    

Thank you for the reply Rey.  I’d also say that the gray seems somewhere between blue and yellow, with yellow indicating complex, and not “bad” per se.  And yes, the physics weights remain the same; only the colours, and as Aquila has now pointed out, the display, change:

PhysicsDemo2.png

I think it is also important to realize (and I am guessing you do) that just because the uploader came in with a low land impact, that doesn't make it better. The only time that I have found that the uploader does a stellar job (STELLAR) is on house size models or larger that are basically cubish. Your build is not "cube" at all and I am guessing (I really didn't cam out to see when I was there ) that the model breaks up nastily at a fairly close distance (with LODs set at 2 anyway). 

I have been making some large buildings for my sim build -- larger than I normally do -- and their land impact is fairly high (still way under a hundred for any of them) BUT you can see most of them from a VERY long distance and that is what I wanted.  So "use" comes into play here and if the build is for YOU, then you can decide just how light it can be and still work well in the setting you plan it for.  

If you are selling things, then that is a slightly different story or "should" be IMHO :D.

Meanwhile many of us learned about those colors -- and I WAS wondering! TY

 

Edited by Chic Aeon
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“I think it is also important to realize (and I am guessing you do) that just because the uploader came in with a low land impact, that doesn't make it better.”

Correct  :) I make my own lower LOD models (You’ll remember that we’ve discussed this before).  This can often mean a higher LI, but that’s a “penalty” I’m perfectly willing to pay to keep the objects intact, from any distance, with the default viewer setting of 1.125. Unfortunately, I can only hope that it’s also a “penalty” the residents who purchase them are willing to pay. 

Short story:  About two weeks ago, Chic, I bought some rugs, a sweater and a pair of shorts from two different events.  Each cost more than 200L, minimum.  The rug, it turned out, had all its lower LODs zeroed so it disappeared when I stood only a few meters away from it.  The sweater and the pants had no Lowest LOD, perhaps even the Low LOD had been zeroed, as they both would disappear at 20 meters.  I contacted the designers (You’d think you’re contacting Henry Kissinger and Associates with all the contacting rules and conditions they put in their profiles!).  One told me that I need to raise my viewer’s LOD to “5 or 6”, and the other told me that my viewer must be running on a “very old system”.  Naturally, I deleted these items from my inventory, and didn’t bother the rug maker additionally about the physics of the rugs making one hover a meter and half above them.

“Your build is not "cube" at all and I am guessing (I really didn't cam out to see when I was there ) that the model breaks up nastily at a fairly close distance (with LODs set at 2 anyway).”

Yes breaks up horribly with those uploader settings.  I used the minimum amount of geometry for the High model (the walls are not quite curved, but give the illusion) in order to use it for the Medium slot, as there was nothing that could be removed, then reduced the 309 tris/178 vertices of the High/Medium model to 41 tris/44 verts for the Low, with the aid of a baked alpha texture.  The Lowest is 23 tris (I was using 7 materials).  It’s part of a three-storey treehouse, which has a total of 230 LI.

Chic, I must say, your “I almost never make my own LODS” earlier was quite a surprise, as your builds have very good LODs. 

Edited by Devriv
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4 minutes ago, Devriv said:

(You’d think you’re contacting Henry Kissinger and Associates with all the contacting rules and conditions they put in their profiles!).

LOL, so true! xD

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2 minutes ago, Devriv said:

This can often mean a higher LI, but that’s a “penalty”

In this particular case you can reduce the effective land impact a bit by making the floor as a separate mesh from the walls. If you can also split the walls into three separate meshes, you should be able to get the whole thing down to 2 LI. You may not gain anything in total though - it depends on what else it is linked to.

 

8 minutes ago, Devriv said:

I can only hope that it’s also a “penalty” the residents who purchase them are willing to pay. 

In my experience low land impact doesn't sell. I made a series of 1 LI houses half a year ago and I still haven't sold a single one. ;)

 

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2 hours ago, ChinRey said:

In my experience low land impact doesn't sell. I made a series of 1 LI houses half a year ago and I still haven't sold a single one. ;)

 

That's because, here in RL Keswick, we are all used to 1 LI houses (along with the 250 LI rain clouds and the 0.05 LI internet), and come to SL for an improvement. :)

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5 hours ago, anna2358 said:

That's because, here in RL Keswick, we are all used to 1 LI houses...

Oh, I've made a mistake then. My Keswick series of cottages are high LI - some of them almost 10.

But seriously... I know this is blatant threadjacking but since the original question is answered I hope it's ok. I've always wondered about those houses. 1 land impact, extremely low lag, perfect LoD ... there should be at least a small market for that in Second Life but there isn't and I can't understand why.

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I have a 2 LI skybox that has been selling well since its appearance on the marketplace. I made it originally for a friend for a shop on a 512 (it fits the complete 512). It is basically a box of course but had interesting inside baffles built in and I made it so that  you could see out the ends if you so choose and added some nice textures. 

I think that often it is MARKETING more than the products that decide sales. The Marketplace is SO extensive (and often difficult to search) that it is much like looking for information on the Internet. You may find what you are looking for or you may only find OTHER things and hence go with what you find. 

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1 hour ago, Chic Aeon said:

I think that often it is MARKETING more than the products that decide sales.

 

1 hour ago, anna2358 said:

'If you don't promote, something terrible happens: Nothing'

Well, nobody's ever going to invite me to any of the big events or feature my builds in any well known blog so the only really efefctive marketing channel I have, is word of mouth. That's slow but it works very well in the long run, But I wasn't really talking about my sales in general - they are slowly but surely increasing - but those specific houses. It's something people say they want and I'm the only one who can offer it to them and still no sales whatsoever.

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Since prim limits were recently substantially increased, I think low prim stuff has lost a little value. I know now if something adds a prim or two and looks better, I will likely go with it. 

 

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While promotion can make a difference indeed, I think the Keswick example plays a significant factor as well. Although everybody wants low prim, it doesn't matter that much when it comes to houses it seems. We had this discussion right from the beginning of the introduction of mesh. My standard phrase has always been, "not everything has to be 1 prim/LI". And someone said, "right, nodody lived in a simple prim cube house before mesh either."

Actually, lots of houses had several hundreds of prims before mesh, and people didn't complain about the count much either. As long as it's a nice home that represents "something" as well, people seem quite fine with higher prim counts. Even when there are no prims left for furniture anymore.xD

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38 minutes ago, arton Rotaru said:

While promotion can make a difference indeed, I think the Keswick example plays a significant factor as well. Although everybody wants low prim, it doesn't matter that much when it comes to houses it seems.

Yes and that brings us back to where my rant started:

14 hours ago, ChinRey said:

In my experience low land impact doesn't sell.

Unfortunately for me, that means I've wasted three years of my life. That's the time I have spent learning how to make the most efficient mesh Second Life will ever see.

I still feel that has a value because it means you can have fuller and more varied landscapes without having to worry about the prim count or lag and you can have open landscapes and actually see the items a sim or mroe away - not just some scattered triangles. But very few people in SL see it that way and I don't have the time and energy to start all over again with a flashier, more commercial product line, Last month I finally got to the point where I don't actually have to pay for the privilege of providing services to Second Life and Linden Lab and I guess that's all I could hope for.

Oh, and sorry about sidetracking this thread. In case somebody wonder why I finally couldn't control my frustrations anymore: I discussed those 1 LI houses with a friend of mine who's working in marketing in RL yes (he couldn't understand why they don't sell either). Next thing I did was log on to the forums and read Devriv's comment about keeping the LI down.

Edited by ChinRey
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