Jump to content

More than eight materials per mesh object now?


Chic Aeon
 Share

You are about to reply to a thread that has been inactive for 2619 days.

Please take a moment to consider if this thread is worth bumping.

Recommended Posts

According to Inara Pey's run down of the new Firestorm viewer --- " Firestorm 4.7.5 includes the updated mesh uploader from Linden Lab, as seen in the SL viewer 3.8.4.305119 release.

This feature modifies the mesh importer to (optionally) improve debug output, perform name-based LOD association, and handle models with many materials, and allows models with more than 8 unique faces to be imported."

 

So since I know some of you use the Linden viewer and have had this for awhile (I have not updated FS as there is little that I care about that is new except "perhaps" this) -- does this mean that one mesh object can have a dozen or more materials defined (more than eight anyway) and is there a limit?  

That certainly sounds like what it is saying. I frequently use a lot of materials (sometimes in place of what I suspect I should be using vertex groups for (on my list)) and so that I have more options with specular options and such. I can't actually think of a time when I needed more than eight materials but I am also making more complex and possible larger (more areas joined before uploading) than I have in the past.

So any info would be appreciated. Thanks.

 

 

  • Like 2
Link to comment
Share on other sites

The limit of 8 materials per mesh remains. The only thing that's new is, that you can import meshes with more than 8 materials. These will be split into multiple meshes, each with no more than 8 materials, automatically when imported.

There is one thing to mention perhaps. During the beta phase of this, the pivot points of the split meshes remained at the center point of the single mesh, before the splitting. So the split meshes would have off center pivot points. This could be used as an advantage, offsetting pivot points on purpose, but you could also create some undesired results perhaps.

I don't know if this is still the case though. But I guess it still is. Personally I never tried a mesh with more than 8 materials. Because the fewer materials, the better the performance. Even a single mesh will be split into multiple meshes in the render pipeline, for each material. I always try to keep at 1 material/mesh whenever possible.

 

  • Like 2
Link to comment
Share on other sites

Thanks. That was SO not what I thought they were saying. I use different materials so that I can have specular maps and features (light) etc on different surfaces but I may be making completely different types of things.

 

Appreciate the input.

  • Like 1
Link to comment
Share on other sites

That does provide an easy way to offset the pivot/origin, but, as with the older methods, it also means the bounding box of each of the meshes is that of the combined linkset. When the splitting produces different sized or widely spaced objects, that can have very large effects on the LOD switching and download weights. These may then be difficult to control, as it means you have to control the splitting by ordering the materials (if I recall correctly, this is now alphabetical in LL viewer - not tested in latest release*). There are also horrible things that can happen with the splitting if materials have > 21844 triangles. As usual, you will get better control if you do the object splitting (and pivot offset) yourself before uploading, instead of relying on these automatic hacks.

*Tested it - yes, it's alphabetical now. Is it in Firestorm too?

  • Like 1
Link to comment
Share on other sites

My best advice is: do not use this function, unless it's to exploit the bug undocumented feature Arton and Drongle mentioned.

Like everything else the uploader is supposed to do automatically for you, it's horrendously inefficient and splitting a mesh manually into separate pieces with eight or less faces each is dead easy in Blender and probably in other 3D editors too.

A while ago I posted a thread about how 4 LI became 44 with reduced quality when I used the uploader's automatic functions rather than do the job properly:

https://community.secondlife.com/t5/Mesh/Why-not-use-uploader-generated-LOD-models/td-p/2969975

What I forgot to mention in that thread was that only about half of that excessive LI was caused by the poor simplification algorithm used for the LOD models. The rest was caused by how badly the uploader handles a mesh with ten (if I remember correctly) faces.

  • Like 1
Link to comment
Share on other sites


Drongle McMahon wrote:

(if I recall correctly, this is now alphabetical in LL viewer - not tested in latest release*).

...

*Tested it - yes, it's alphabetical now. Is it in Firestorm too?

Thank you Drongle, you always come up with interesting and useful bits of info! ^_^

I've never been sure of this and never got around to testing. I've just made it a habit to have the materials listed alphebetically in Blender too so it wouldn't matter how the uploader sorted them.

  • Like 1
Link to comment
Share on other sites

 

Hi :)

I had wondered, if a mesh object with more than 8 materials got split automatically into 2 or more separate objects, how the Uploader would handle the physics and assumed it couldn’t know how to recreate the physics properly and so be unusable.

This morning after reading this thread I thought I should try anyhow.

I created 10 posts in Blender, 0.4 x 0.4 x 5m high with 2 meters spacings . Each was assigned its own material.

The Physics mesh was the same posts but with the end faces deleted:



 

When it came to uploading the Physics mesh was not showing in the preview window:



when rezzed and edited t ochange the Physics Shape type thers was no prim option:



So the uploader solves the problem of physics for automatically split objects by simply ignoring the Physics mesh and uses the default convex hull when the objects are rezzed !

  • Like 2
Link to comment
Share on other sites

Ugh! I hadn't looked at that. I'll have to look at the code and see how that happens. Surely they can't just have forgotten about it? I assume both objects get the CH of the whole linkset. rather than each getting their own proper hull. Is that right? Anyway, that's yet another good reason not to use the auto model splitting. I think we have to assume that this whole thing was done just to accomodate people who wanted to upload multi-material objects made by other people and who don't know how to use 3D software themselves (i.e. .......s).

  • Like 1
Link to comment
Share on other sites


Drongle McMahon wrote:

I think we have to assume that this whole thing was done just to accomodate people who wanted to upload multi-material objects made by other people and who don't know how to use 3D software themselves (i.e. .......s).

That's my impression too.

So, in case somebody from Linden Lab or others who don't follow the mesh forum regularly happen to read this:

To clear up any possible misunderstandings about the four L's of SL building: What we want is less LI, less Lag, more LOD and better Looks. Not the other way round.

Link to comment
Share on other sites


Drongle McMahon wrote:

................ I assume both objects get the CH of the whole linkset. rather than each getting their own proper hull. Is that right? .............................

 



Just to note: I labeled my 10 materials from 1 to 10, not thinking that the material order would be 1,10,2,3,4,5,6,7,      8,9  :)

The last 2 screen shots show, as Arton explained earlier, how the second object's rotation point is now offset.

 

Link to comment
Share on other sites


Aquila Kytori wrote:

The last 2 screen shots show, as Arton explained earlier, how the second object's rotation point is now offset.


The big question is, is this something we can actually use or is there a risk LL will fix the bug at some point?

Link to comment
Share on other sites

Me, personally? probably not  :)

And for auto splitting meshes ? nope.

At the moment I am working on some simple LOW LI modular building blocks that could benefit from a few more materials faces. Most of these 2 story modules have materials faces: 1outside_wall, 2roof, 3ceilings, 4corridor_floor, 5corridor_wall, 6room_wall, 7room_floor, 8door_window_ frames. Mostly its the same 8 tilable 512 textures being used across all the modules.

The problem arises when the ground floor room walls and upper floor room walls need to have different wall textures etc. The  usual compromise is, for example making the room_floor texture have the same material as the corridor_ floor texture for that particular module. So a few more materials added without splitting the mesh would have been useful :)

  • Like 1
Link to comment
Share on other sites


Aquila Kytori wrote:

And for auto splitting meshes ? nope.

That goes without saying ;)


Aquila Kytori wrote:

The problem arises when the ground floor room walls and upper floor room walls need to have different wall textures etc. The  usual compromise is, for example making the room_floor texture have the same material as the corridor_ floor texture for that particular module. So a few more materials added
without
splitting the mesh would have been useful
:)

In a case like that, wouldn't it be better to split up to balance download and server weight?

 

Anyways, I may have done something really stupid, I posted this:

https://jira.secondlife.com/browse/BUG-10752

And yes I know, bringing it to their attention greatly increases the risk that they'll try to "fix" it. But we don't really have much to loose. They might have suddenly decided to do it anyway and what good is a feature that may be gone tomorrow?

Link to comment
Share on other sites

Now aren't you all glad I brought this up? 

LOL. I knew you would want to know if you didn't already.

 

And I do agree that it seems to accommodate the illegal (remember we all took that uploader test and signed the TOS a few times) importing of free to use web mesh. I really can't see why I would NEED to use this except as mentioned in a large project ( I was thinking on a Victorian recycled house in the process).  Nothing I would need often --- even if it worked well.

 

And yes, sometimes (often) it is much better to upload in pieces and then link (LI wise and all). It might have been nice if it actually worked as it seemed to SUGGEST :D, but oh well.

 

And there are apparently a lot of issues with the new uploader and changes to rigging. Since I don't do that except VERY simply if at all I won't worry about that.

 

Thanks for all the input. I am going to put the link to this thread in a Google group for those that want to check out the details.

 

 

  • Like 1
Link to comment
Share on other sites


Chic Aeon wrote:

Now aren't you all glad I brought this up?

Yes. ^_^

 


Chic Aeon wrote:

And I do agree that it seems to accommodate the illegal (remember we all took that uploader test and signed the TOS a few times) importing of free to use web mesh.

Not sure what you mean by illegal. Yes, there is a lot of mesh uploaded by people who clearly didn't make the items themselves, probably don't know how to make mesh themselves, and unfortunately don't know how to make mesh work in SL. But I'm sure it's all open soruce, public domain items or items where the creators have given explicit permission. Anybody who tries to sell illegal content in SL will have the LL SWAT team dropping on their head like a ton of prims before they can ssay "Level Of Detail".

Link to comment
Share on other sites


Aquila Kytori wrote:

 

Hi
:)

I had wondered, if a mesh object with more than 8 materials got split automatically into 2 or more separate objects, how the Uploader would handle the physics and assumed it couldn’t know how to recreate the physics properly and so be unusable.

This morning after reading this thread I thought I should try anyhow.

I created 10 posts in Blender, 0.4 x 0.4 x 5m high with 2 meters spacings . Each was assigned its own material.

The Physics mesh was the same posts but with the end faces deleted:

More than 8 materials physics test.png

 

When it came to uploading the Physics mesh was not showing in the preview window:

More than 8 materials physics test 2.png

when rezzed and edited t ochange the Physics Shape type thers was no prim option:

More than 8 materials physics test 3.png

So the uploader solves the problem of physics for automatically split objects by simply ignoring the Physics mesh and uses the default convex hull when the objects are rezzed !

There's a bug report for that at https://jira.secondlife.com/browse/BUG-10170

Link to comment
Share on other sites

Hi :)


Whirly Fizzle wrote:


There's a bug report for that at

 

I don't think that is the same issue.

When I uploaded the same mesh with only 8 posts, and 8 materials the physics showed up as expected in the preview window and was correct when rezzed and edited to change the Physics Shape Type from Convex Hull to prim.

This Physics problem mentioned in message 7 only happens when uploading a mesh object with more than 8 materials.

Second Life 3.8.6 (305981)

Link to comment
Share on other sites

Ahhh  thanks.

I just checked and BUG-10170 is actually listed as fixed in a later version of the importer viewer.

MAINT-5601 [importer-RC] Physics model not previewed, physics model not applied to mesh on upload - is a resolved issue in http://wiki.secondlife.com/wiki/Release_Notes/Second_Life_Release/3.8.4.305119

Maybe it was never fixed for the case of meshes with more then 8 materials though?

Worth filing a new JIRA issue for anyway.

 

 

Link to comment
Share on other sites

So it doesn't use the bounding box of the combined meshes for the CH physics, although it does use it for LOD and pivot (and stretching handles). Stranger and stranger. Also, reproducing your case, I find that if you leave all the 20 end faces there, the triangle physics works as you would expect. Deleting just one of them results in the behaviour you described. That seems to be specifically for >8 materials, as deleting the end faces on a model with 8 pillars/materials works as expected.

Link to comment
Share on other sites

I did same test as Aquila, and Drongle did (meshes exported from 3ds max).

The physics shapes only show up (capped, or without caps), and work as type Prim in-world when I load the mesh from a .slm file.

When loaded from slm, selecting the physics mesh again will make it show in preview then. I guess the slm has the split mesh information already stored, and hence the physics shapes are applied correctly.

Link to comment
Share on other sites

It could also be that Blender does not generate the correct DAE code for a mesh with more than 8 materials?

That seems most unlikely because eight materials has no special significance in Blender. That is to say, there is no discontinuity in the dae that arises with nine, as compared to 8, materials. On the other hand, there is a major discontinuity in the uploader, which starts to divide the model.

Link to comment
Share on other sites



Not sure what you mean by illegal. Yes, there is a lot of mesh uploaded by people who clearly didn't make the items themselves, probably don't know how to make mesh themselves, and unfortunately don't know how to make mesh work in SL. But I'm sure it's all open soruce, public domain items or items where the creators have given explicit permission. Anybody who tries to sell illegal content in SL will have the LL SWAT team dropping on their head like a ton of prims before they can ssay "Level Of Detail".

Well according to the TOS of August 2013 and not changed in any manner I have heard of since then :D open source is not supposed to be uploaded as the uploading person in this case does NOT hold the copyright.

 

Not sure you were here then,  but there was a huge (HUGE) uproar -- not because of the uploading of 3rd party goods but for many other reasons. And I noted today that CG Textures who has changed there TOS since I was there last now has it written in that you cannot use any of their textures in ANY LINDEN PRODUCT *wink*. 

 

So anyone that hasn't made their own mesh object is not supposed to be uploading. And  it is surprising that there was this change if that is what it was aimed at. To me that is doubtful.

 

As I was working on a fairly complex object in Blender cycles today I noted that if you want to use the full extent (well, as much as I know anyway) of Cycles then there could certainly be occassions when you would need more than eight materials. You can of course work around that and I have, but having the option to keep it easier would be good.  I have four five materials on a window now. If I want to upload it with the wall and corners which was my original plan that will add another three.  So you see it doesn't take too long to use up that EIGHT :D.  

I will keep it to eight though and just upload in pieces as I have before. Enough new stuff in this project as it is.

 

 

Link to comment
Share on other sites

You are about to reply to a thread that has been inactive for 2619 days.

Please take a moment to consider if this thread is worth bumping.

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...