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OpenSubDiv Testing and Discussion Thread
Posted: 23 April 2013 09:31 PM   [ Ignore ]   [ # 16 ]
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niccipb - 23 April 2013 07:12 PM

The biggest problem is that Pixar is only part of the equation… Microsoft R&D played a big role in the developed of the OSD platform and the license is handled by Microsoft through MPL ( Microsoft Public License )

So bottom line is, no matter how much Pixar want’s OSD to be available to Blender, if Microsoft say no then it’s a no….

nicci… smile

Okay, I looked up the issue and I think I understand why it’s a problem.

GPL or General Public Licence is basically for public domain software.  Anything that has a GPL is.  MSLP is not.  It is designed to work with commercial software, thereby making them incompatible.

I cannot imagine AutoDesk, Pixar or Microsoft deciding to throw what they developed into the public domain.  Blender is going to have to bend in order to get it… maybe via plugin or converter.

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Posted: 23 April 2013 10:46 PM   [ Ignore ]   [ # 17 ]
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wancow - 23 April 2013 06:59 PM

I don’t understand the problem.  All Pixar has to do is issue a special licence to Blender… haven’t they thought of that yet?

A single exception for Blender isn’t very helpful, either.  There is a lot of GPL software out there that would still be left out, like LuxRender.

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Posted: 23 April 2013 11:01 PM   [ Ignore ]   [ # 18 ]
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Something tells me that a plugin could be made for anything OpenSubDiv so that LuxRender could read it.  Blender isn’t just a render engine, it’s a suite, which would require it be able to edit OpenSubDiv.  There’s a huge difference there.

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Posted: 23 April 2013 11:16 PM   [ Ignore ]   [ # 19 ]
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Hi…

wancow - 23 April 2013 09:31 PM
nicci - 23 April 2013 07:12 PM

The biggest problem is that Pixar is only part of the equation… Microsoft R&D played a big role in the developed of the OSD platform and the license is handled by Microsoft through MPL ( Microsoft Public License )

So bottom line is, no matter how much Pixar want’s OSD to be available to Blender, if Microsoft say no then it’s a no….

nicci… smile

Okay, I looked up the issue and I think I understand why it’s a problem.

GPL or General Public Licence is basically for public domain software.  Anything that has a GPL is.  MSLP is not.  It is designed to work with commercial software, thereby making them incompatible.

I cannot imagine AutoDesk, Pixar or Microsoft deciding to throw what they developed into the public domain.  Blender is going to have to bend in order to get it… maybe via plugin or converter.

That’s not right… GNU GPL is not public domain, that would mean nobody owns it… GPL is for “free software”, meaning free for the user to use and distribute as the wish, provided that they do so within the terms of the GPL… buy providing access to all of the source…

The MsPL does basically the same thing, but were the problem apparently comes in is that the FSF ( the publisher of GNU GPL ) believes that it is not strong enough to protect software that is under the GPL… and to correct what I posted before about GPL v3, I guess the FSF has now decided that that’s not compatible with MsPL either…

But from all the articles I’ve read about the compatibility issues, it seems to me to be all about the FSF (Free Software Foundation) wanting to insure that GPL software is protected from lawsuits and court actions stemming from patent and copyright claims… to date they have been pretty successful to that end… and I guess the very brief wording in the MsPL leaves a legal door somewhat open for lawyers to exploit…

On the OpenSubDiv license page they do acknowledge the issues with the open source communities, and they do say, quote

We’ll continually monitor this license and if it’s not doing the job for an important part of the graphics community, we’ll try to address it.

I will also correct what I said before about Microsoft having a say in it, because also according to the license page, it was Disney legal that chose the MsPL…

Anyways, there still hope that one day OSD may find it’s way into Blender and other open-source 3D software if the communities are large enough and really want it…

nicci… smile

 

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Posted: 23 April 2013 11:17 PM   [ Ignore ]   [ # 20 ]
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So right now the only common interchange format that has extensions for supporting the vertex edge weights is FBX?  Googling OpenSubDiv and plymesh didn’t come up with any hits.  Plymesh is easily extensible, but Pixar needs to define standard property names to use in plymesh so plymesh tools are consistent when reading/writing them.  (My main interest is, of course, LuxRender, which uses plymesh for its primary external mesh file format.)

I wonder if the Studio SDK has been updated to allow plugins to access the vertex edge weights so they can properly export them to other renderers like LuxRender when/if they gain support for OpenSubDiv.  Although in current released versions of Studio, when you retrieve the mesh for a SubD object, it gives you the fully calculated SubD mesh, not the base mesh.  So exporting to LuxRender, for example, wouldn’t actually need to know about OpenSubDiv as the mesh is pre-computed.  It just means the mesh files are larger.

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Posted: 23 April 2013 11:29 PM   [ Ignore ]   [ # 21 ]
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Hi…

cwichura - 23 April 2013 10:46 PM
wancow - 23 April 2013 06:59 PM

I don’t understand the problem.  All Pixar has to do is issue a special licence to Blender… haven’t they thought of that yet?

A single exception for Blender isn’t very helpful, either.  There is a lot of GPL software out there that would still be left out, like Lux.

That’s true if Lux were to support OSD directly… meaning that OSD object data is written in the scene file and Lux interprets the info during rendering…

The way around it is that the exporter, like Reality or Luxus, reads the OSD data and converts it to the regular Lux scene file…just as they do now when dealing with Genesis SubD… the downside to this method is that Lux doesn’t benefit from OSD at all…

nicci… smile

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Posted: 23 April 2013 11:32 PM   [ Ignore ]   [ # 22 ]
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I would ask the Reality and or Luxus developers about that…

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Posted: 23 April 2013 11:35 PM   [ Ignore ]   [ # 23 ]
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niccipb - 23 April 2013 11:29 PM

The way around it is that the exporter, like Reality or Luxus, reads the OSD data and converts it to the regular Lux scene file…just as they do now when dealing with Genesis SubD… the downside to this method is that Lux doesn’t benefit from OSD at all…

nicci… smile

  Oh yes it would.  Because OpenSubDiv, when you bake the mesh, results in fewer polygons than does standard CatmulClark.

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Posted: 23 April 2013 11:48 PM   [ Ignore ]   [ # 24 ]
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Yes, as of now, it would be up to Pret-a-3D and Spheric to extend exportability of OSD meshes to Lux… and depending on levels of sub-division, the mesh files could be quite a bit bigger…

I do believe that FBX is currently the only fully integrated cross-platform format, but obviously DSON (.duf, .dsf) supports it… and the beta DSON importer for Poser supports it… so I don’t see why other formats that are extensible couldn’t also support it…

But then the license issue again comes up in regards to Lux… the Lux scene files could not contain any script code from OSD and remain compliant with GPL… this is the main reason Blender doesn’t fully support FBX files…

nicci… smile

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Posted: 23 April 2013 11:57 PM   [ Ignore ]   [ # 25 ]
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wancow - 23 April 2013 11:35 PM
niccipb - 23 April 2013 11:29 PM

The way around it is that the exporter, like Reality or Luxus, reads the OSD data and converts it to the regular Lux scene file…just as they do now when dealing with Genesis SubD… the downside to this method is that Lux doesn’t benefit from OSD at all…

nicci… smile

  Oh yes it would.  Because OpenSubDiv, when you bake the mesh, results in fewer polygons than does standard CatmulClark.

Actually I believe that when you convert the SubD mesh, it turns that sub-division into real mesh…meaning more polys…

The benefit of OSD incorporation into the software can be seen by your examples, very few levels of SubD are needed to create very smooth renders… because the renderer also supports OSD…

For Lux to have that same benefit it would have to directly support OSD, otherwise the baked mesh from the exporter has to turn all of the SubD mesh into real mesh…

nicci… smile

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Posted: 24 April 2013 12:12 AM   [ Ignore ]   [ # 26 ]
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when you render, my understanding has always been that either the meshes get backed before or during render.  Baking OpenSubDiv meshes would give you the same number of polygons that you would have if you didn’t bake it at render time.  The difference is that catmulclark would bake more polygons, and OpenSubDiv would bake fewer.

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Posted: 24 April 2013 12:25 AM   [ Ignore ]   [ # 27 ]
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Hi…

Yes I do believe that’s correct, but were the difference comes in is whether the renderer supports OpenSubDiv… 3Delight does, but Lux does not…

So for D|S you can use few sub-divisions using OSD and 3Delight will render it looking like a high poly model… but if you send the low poly or low SubD mesh to lux, it won’t look as smooth because it lacks the sub-division that OSD provides…

I know that Lux supports sub-division, but in order to take advantage of the creasing some level of pre-baking of the SubD into real mesh will probably be needed… but that will be for the experts to figure out… wink

nicci… smile

edit: BTW - I’m really enjoying the topic… it’s allowing my brain to work on something other than the normal of my day job…. tongue wink
although I just remembered I said earlier that I was going to do some OSD tests on some of my Blender projects… tongue rolleye

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Posted: 24 April 2013 05:17 AM   [ Ignore ]   [ # 28 ]
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I saw a presentation on Ptex and OpenSubDiv quite a while back, when OSD I think it was, was first being announced. Now it could be my memory is playing tricks on me or that I misinterpreted what was being said but I had gotten the impression that Ptex and OSD were separate but ‘joined at the hip’ so to speak as in two sides of a coin. That is, the two together would bring about this revolution in 3D compatibility. From what’s been said here, I get the impression that the licensing is totally different between them and this joined at the hip concept would only be true under very restricted circumstances, as in when using specific software. Can anyone clarify this?

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Posted: 24 April 2013 08:12 AM   [ Ignore ]   [ # 29 ]
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Gedd, the liscensing will be an impediment toward implementation of OSD, but will only affect the end user in that it may not be available to them in certain software.  What I’m seeing with Blender, for instance, is that it’ll probably get OSD through a plugin modeller.  I can’t imagine any other solution for them.

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Posted: 24 April 2013 09:34 AM   [ Ignore ]   [ # 30 ]
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Great discussion.  Very enlightening…

Just for the sake of clarity for those reading this thread I would like to make a correction (sorry, nicci).

The Blender Ptex development was by Nicholas Bishop, and put on the back burner in favor of his baby, Sculpt in Blender.  He was working to implement dynamic sculpting to his sculpt module.  He is the original author of the sculpt module which was originally a stand-alone open-source program named SharpConstruct.

I’ve never seen any evidence of him helping on coding of Cycles, nor believe he would have the time (with all his ongoing projects).

Hopefully, he will get back to coding Ptex at some time in the future now that he has finished Dynamic Sculpt (for the most part), and find a way to implement it alongside of Vertex Paint and not a substitute for it.

If not, or if no other coder takes up the challenge, it looks like we will have to purchase 3D-Coat to (Ptex) paint.  Unless, by some miracle, DAZ is secretly working on Hexagon 3, and is implementing both Ptex and OpenSubDiv (we all can dream) to work in tandem with DAZ Studio.


Regarding licensing, I don’t really follow the licensing all that closely, but I was wondering if the Blender issue has anything to do with the fact that “we the people” purchased the right for the software to become open-source from NaN.  Since it was a fund raising venture of such magnitude, I wonder if licensing was locked due to some sort of non-profit entanglement.

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