Opensubdiv 3 released by Pixar

Piotr_Adamowicz · June 28, 2015, 11:45pm

Both Blender and Maya have supported creases for years. You can’t export a model with creases because blender’s FBX import/export doesn’t support it. Or at least it didin’t the last time I tried. I mentioned it to Campbell over IRC a couple years ago. Maybe it was implemented?

Speaking of creases, this would probably be a good opportunity to fix this little papercut:

When extruding or insetting creased edges, the new edges should be creased too. Also true for sharp edges, freestyle edge marks and bevels. Not so sure it would actually be better behavior for seams, but it probably wouldn’t be worse either, just different, I guess?

Alternatively, this behavior, removing the tag from the “original” edges of the extrusion might also be interesting:

Also, the manual keyboard input for creases should be absolute, not relative. To set it to zero you should only have to type 0, not -1. This is important because you often want to set edges to the exact same value as another edge somewhere else. With relative input you have to either zero the crease beforehand, do math or eyeball it.

SoulVector · June 29, 2015, 2:19am

Anyone know if there have been any discussion about Loop Scheme implementation for triangles or is all the schemes included for that matter or only catmull clark? Loop is extremely valuable addition to hard surface edges with sharp corners topology and also spherical poles to have a more rounded curvature. It is included in OpenSubdiv however it needs to implemented and exposed to the user.

http://graphics.pixar.com/opensubdiv/architecture.html

fahr · June 29, 2015, 3:40pm

I think fbx creases are supported to some degree, but not sure. Obviously opensubdiv will need support across ALL relevent parts of blender. (modeling, animation, rendering in cycles AND import/export). I hope it gets the full treatment, but it will take a while regardless.

theApe · June 29, 2015, 10:16pm

It´s not about supporting subdivs or creases, it´s about supporting them in a consistant, predictable way, ie having the same implementation across all applications.

SoulVector · June 29, 2015, 11:59pm

That would be really nice so that all expected features are implemented. Sorry if I´m sounding paranoid but sometimes I get the feeling that Subdivs are implemented in a half-way across many applications. That is not about Blender specific but in general. As an example Maya have not implemented Loop Scheme for triangles in a way that it is exposed to the user in a easy way even though it is in Mental Ray for some time ago and well it would be nice to see BI making OpenSubdiv as supposed to.

Piotr_Adamowicz · June 30, 2015, 12:31am

What are you all talking about? As far as export is concerned it’s a float per edge and per vertex, it either works or doesn’t - there’s no degrees, or consistency or predictability involved.

It’s up to each app’s implementation of Catmull-Clark to make certain the creases look consistent across apps, but that’s entirely unrelated to being able to import/export the crease values.

Or else I’m not understanding something.

theApe · June 30, 2015, 3:01am

I´m sorry, I was under the impression this was a thread about Opensubdiv, an implementation of Catmull-Clark subdivision surfaces… my bad.

BTolputt · June 30, 2015, 3:41am

Without being mean here, Piotr, it’s that you’re missing something. Opensubdiv being used everywhere makes certain that creases look consistent across apps. There is no point exporting a float per edge/vertex if different apps put those values through different code (resulting in different creases).

A major point of Opensubdiv by the authors was to get consistency across multiple applications.

Piotr_Adamowicz · June 30, 2015, 4:56am

Um, yes, that’s kind of obvious. There seems to be some kind of confusion here. I was responding to fahr talking about exporting creases to Maya after we get OpenSubdiv in Blender. Presently there’s no way to export the crease values at present. OpenSubdiv won’t change that.

The implementations in current Blender, Maya, Modo and Opensubdiv, though they’re different code, all give you pretty much the same limit surface. Max’s turbosmooth is different, and I’m not so sure about zbrush, but still, it would make plenty of sense to be able to import/export the creases even today. OpenSubdiv is needed not because it gives you a different result than all the other Catmull-Clark implementations, but because it’s blazing fast and pleasant to work with. Presently creases are not used very often because it’s just painful to work at 5 subdivisions or so, in any app.

manuel_songokuh · July 30, 2015, 10:45am

hello
sorry i want to use/test opensubdiv blender , where i can download snapshot 2.76 (including opensubdiv) but i dont find …
http://wiki.blender.org/index.php/Dev:Doc/Projects
there is info: http://wiki.blender.org/index.php/User:Nazg-gul/OpenSubdiv
i can risk to use last snapshot with opensubdiv…(linux 64)…

theApe · July 30, 2015, 11:42am

I don´t think there are any builds out there with Opensubdiv enabled. You´d have to build it yourself.

pecador · July 31, 2015, 3:33am

As far as I know is included in latest build. When Subdiv is the last modifier Opensubdiv is applied by default.

marcoG_ita · July 31, 2015, 3:40am

To test OSD you need to grab dev branch, not master -> https://github.com/Nazg-Gul/OpenSubdiv/tree/dev

As mentioned here -> https://developer.blender.org/rB3d364896725db8336d785ba6cf977b62c0f2c0ce

theApe · July 31, 2015, 4:18am

Included in source but not in builds by default. You need to enable it when building, meaning it is not available through buildbot, for example…

YAFU · July 31, 2015, 6:55am

When OpenSubdiv be compiled in buildbot by default, I think you should be able to find some related options in User Preferences > System

I still have not been able to successfully compile Blender with OpenSubdiv enabled.

slipknot66 · July 31, 2015, 8:08am

Is Opensubdiv 3 related to the render time displacement feature that is already present in Blender? Just wondering, when this feature will be 100% working, especially with UVs.

Ace_Dragon · July 31, 2015, 11:14am

It’s not enabled though, Sergey is waiting on Pixar to do a bugfix release that resolves a couple of serious issues (which will be very soon).

I’m thinking it will be enabled by default not long after that.

manuel_songokuh · August 24, 2015, 5:10am

i did download last snapshot blender, there is opensubdiv bit it’s disactive … how i can active for test and try,?
see screenshot…

kettlefish · August 24, 2015, 5:51am

The buildbot version I’ve been using has it in. Can’t remember when I downloaded it, it would have been a few days ago at least:

Using openSubdiv, but I’m not certain it’s working correctly between blender and renderman as the creasing doesn’t look right. I don’t know

The other problem is I have no idea what the best compute option from the list is. I’ll have to go an look that up.

EDIT: the build date is right there on the splash: DOH!
EDIT 2: Just downloaded the current version, which also has it in. I don’t know why it’s not showing up for you manuel.

Sanctuary · August 24, 2015, 6:45am

The reason you have only “None” at the opensubdiv backend list is :

juicyfruit:

To use opensubdiv you need to be able to both render one or more backends AND support all the following OpenGL extensions:
Geometry shader support ( Part of OpenGL 3.2)
GL_ARB_gpu_shader5 ( Part of OpenGL 4.0 or an extension )
glProgramParameteri, glProgramParameteriEXT, glProgramParameteriARB ( Part of OpenGL 4.1 or as an extention )

So it’s “None” in the case your GPU does not support those.
Now for the “CPU” or “OpenMP” backends , apparently the way opensubdiv is currently implemented, even with those backend there is still the need to meet these opengl requirement :

It’s been moved to TODO, so maybe one day full CPU/OpenMP will be available without the opengl requirement along it