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What is the purpose of these "extra" cubes


Chic Aeon
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2 hours ago, Fluffy Sharkfin said:
3 hours ago, Chic Aeon said:

SO HOW DID THEY DO THAT?

Most likely by removing all but a single triangle/face from each of the cubes then using the Solid setting when analyzing the mesh to generate the physics model, since that ignores any part of the mesh which isn't "solid" (i.e. isolated triangles).

 

I suspect, just by using the tools we have. The small cubes are on a separate material face. The creator used GLOD to produce the low LOD model I believe (the squashed but not quite flat pile). A valid mesh must retain at least one triangle for each material and thus the cubes (due to their tiny size almost immediately collapse down into a single face under the GLOD algorithm which you then do not collide with due to its size. 

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13 hours ago, Chic Aeon said:

Except those are cubes, not triangles.  But I will try the solid with a triangle and see if that works -- just in case I need that some day :D. 

They could be represented by a single triangle in the physics model though. A single isolated vertice could be enough but that's fairly advanced mesh making and Beq's illustration only emphasizes what I've already said: this is not a well made mesh. I can't believe it could have been amde by somebody savvy enough to know the single vertice boundign box expanding trick. Certainly not if those cubes were intended as LoD adjusters since the single vertice trick would have worked for that too.

I'm not saying the creator of the mesh stack is a poor mesh maker though, only that he/she was at the time this was made. Everybody had to learn mesh from scratch with little or no help from LL and it wasn't really until 2015-ish qwe started to see any significant amount of decent quality mesh in SL.

Edit: I didn't see Beq's post before I replied. Yes, GLOD's butchery is probably the reason how an unskilled mesh maker could end up with a physics model like this. My subconciousness tries it best to suppress the fact that GLOD exists so I tend to forget how much damage it can do to our lovely meshes. Sometimes the simple answer is the right one. ;)

Edited by ChinRey
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So I did some experiments with some of the suggested ideas here and I did do the single vertices physics model for the triangle part of the model (I didn't try it with a cube but it might work for that too. We can maybe presume it would? Someone else can try that).  

 

It did work as suggested so far as the physics part. I did not need "solid" in order to get the physics mode with lone vertices to work ONLY on the vase. In this case it didn't really help the issue. I suspect that maybe making a few triangles a longer ways away might do it, but this IS sort of a "darker side" model LOL so just making the cage with less square would certainly be an option also. 

Here is how it looks.

 

The one on the right I just used a hexagon without the extra vertices for the triangle. 

So this was a good thread and "I" learned some stuff anyway. So thanks all.  I DO have an idea where this knowledge will help a bunch and it isn't on wired vases LOL. But that is MY secret. Others can find their own uses. 

 

5a6919db7d3e3_twovases.PNG.692edea92c60491d7f297748c8216dbc.PNG

 

5a6919f2aa249_vasephysics.PNG.3998d3ea3ead74395924e8a81dcac5a6.PNG

Edited by Chic Aeon
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7 hours ago, Chic Aeon said:

I DO have an idea where this knowledge will help a bunch and it isn't on wired vases LOL.

If you want to use it to control LoD, try to place those extra triangles or vertices along the axis that already has the largest dimension. That is one of the mistakes the maker of that book stack made (assuming LoD strengthening was the purpose).

So, if you have a tall vase you want the "bounding box extender" above the actual object:

5a69898cf2ead_Skjermbilde(993).png.b93659785d08a55a32a302857f8b570e.png

. But if it's a low and wide object, you want them on the side (one on each side to avoid shifting the object's center):

5a698ab807334_Skjermbilde(992).png.257d7f7f8ef2790e3998fe99ac250a5f.png

Or, since you're adding geometry anyway, why not make use of it an add a shadow face:

5a698ba3a3948_Skjermbilde(994).png.42b0141c616955945557683d156d12e2.png

(I suppose this goes without saying but if you do add a shadow face, make sure there's an easy way for the owner to hide it or even better, hide it by default and make sure there's a reasonably easy way for the owner to et it to show.)

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Some of the decisions people make are based on personal convenience or solving for a particular thing. I have my doubts something like this will be as hugely technical as many felt, or that it marks them at the time good or bad in a particular way based on someone's opinion. Though it does suggest they are not trimming as much as possible at the end of the workflow.

Some of the basics of SL mesh implementation dictate that the bounding box will be stretched and filled to. Or at least I am pretty sure it was mentioned as a caveat when doing custom physics shapes and why it may not match the visual geometry. A persons personal preference on what object to pad the ratio of the geometry with will likely be based on their selection tastes in the tool they are using. A tiny triangle that may be backface culled is prone to more difficulty to work with and place than a cube. SL's rendering of non-masked transparencies would cover the entire surface or may impact click-through ability in some conditions. So limiting the surface area and making the object humanely convenient at speed seems a likely factor. And I left out points of origin and snaps used for translation, well until now, I just mentioned it.

Though the previous explored possibilities may still weigh into it. My instincts immediately go to workflow, human sanity, a hybrid between tool and target, and time reasons, before anything deeply technical and mathematical.

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39 minutes ago, NaomiLocket said:

Though the previous explored possibilities may still weigh into it. My instincts immediately go to workflow, human sanity, a hybrid between tool and target, and time reasons, before anything deeply technical and mathematical.

Even that may well be overanalyzing.

But wild goose chaes aren't always a waste of time. You may not ever find what you're looking for but who knows what else turn up along the way?

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41 minutes ago, ChinRey said:

Even that may well be overanalyzing.

But wild goose chaes aren't always a waste of time. You may not ever find what you're looking for but who knows what else turn up along the way?

You do have a point there :) and there was certainly some interest.

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5 hours ago, ChinRey said:
13 hours ago, Chic Aeon said:

I DO have an idea where this knowledge will help a bunch and it isn't on wired vases LOL.

If you want to use it to control LoD, try to place those extra triangles or vertices along the axis that already has the largest dimension. That is one of the mistakes the maker of that book stack made (assuming LoD strengthening was the purpose).

Actually I doubt I will use this info to "extend" a bounding box -- or certainly not very often as I rarely make something small like this with so much density. I was more interested in the way to adjust the physics model :D. And  I NEVER include a shadow prim as part of the mesh. If I do add floor or wall shadows to an item it is usually because I need an extra prim for my old but still works great texture change script I wrote in a class (so not a script person) AND I almost always have a shadow on shadow off option in the scripting. Not a fan of cast shadows since I always have shadows on in the viewer.

 

I found  another book while looking through my inventory for decor that had one cube on an edge, just there -- which made even less sense than this example. So it is somewhat of a mystery what folks do to make things work (or not so much as the case may be :D).   I often wonder at myself if I remake an old model (taking longer than it would to just make a new one from scratch but a good reminder of how practice does make you better) at some of the choices I made back then  (insert head shaking emoticon here). 

 

 

 

 

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