OpenSubDiv is on its way back


(captainkirk) #122

But won’t that impact users who don’t have a good GPU?

(wph4) #123

I’m curious about that myself, as I’m on a laptop right now…

(Piotr Adamowicz) #124

If you don’t have a good GPU, in all probability your CPU isn’t all that great either, and so the question is moot. Besides, OSD does have a CPU fallback.

(RaphaelBarros) #125

I wonder if this regression may be a bless in disguise, we may end up having some actual development on MultiRes that allows for better performance after some patches are applied.

One can only hope…

(Gtx) #126

What exaclty is opensubdiv? Do you activate it anywhere? Because 2.8 is REALLY slow when editing meshes or rigging, previewing animations is like 6fps with just a few objects on screen, (I have a good gpu) and I’m worried about that.

(Thornydre) #127

OpenSubDiv is an algorithm to subdivide your meshes (it basically the old algorithm behing SubSurf), and it handles better the creasing edges. In 2.8 it is activated by default, and it does not use the GPU yet, it is planned apparently but it requires more work. I wouldn’t be too worried about the performance, I don’t think there is any doubt about the really good performances of OpenSubDiv, and it will probably be polished during the BETA stage. :slight_smile: Hope this answer to your question !

You can go here if you want more informations :

(Piotr Adamowicz) #128

Please tell me you’re not just basing this opinion on blind faith. The performance drop isn’t even acknowledged in known issues.

(Metin Seven) #129

Yep, and Sergey wrote in this thread that OpenSubdiv will probably not yet be finalized / optimized in the first 2.8 release version.

(Piotr Adamowicz) #130

Great. The one thing Blender did really well, modelling, you will now need an external application for. There’s very few things you’d want to model that will come in under 2000 faces.

(Thinking Polygons) #131

They could keep the “old sds modifier” there, at least until the performance were on par… :thinking:

(Ace Dragon) #132

Sometimes, you have to make a call on disabling the old code completely in order to facilitate a greater amount of testing and feedback.

That being, if you hid new code behind a compiler or debug flag, how many people are going to actually test it other than the developers?

When I downloaded the beta, I noticed the performance regression has already been logged by a user on the developer site (but the list of reports to wade through to find it is huge).


uh… is this a bug or a feature?

I suspect it has something to do with the adaptive bit of the opensubdiv

also, edges are creased to max.


CPU: Pentium G2030

GPU: AMD R7 240 1GB

GPU Driver version: 18.8.2

(nudelZ) #134

what do you expect? turn up the “view” levels and you will get sharp edges… its the same as before execpt much slower ^^


It’s 3 subdivisions though, the result looks like what I’d expect when I lower the crease to 0.99 as opposed to 1

Here’s it at crease = 1 , Subdivisions at 3

Crease = 0.99 , Subdivisions still at 3

(nudelZ) #136

well the shading error is just a bug - open the same scene in 2.79 and compare the results and speed ^^

(artell) #137

When I downloaded the beta, I noticed the performance regression has already been logged by a user on the developer site (but the list of reports to wade through to find it is huge).

I did, but maybe other users reported that too? Sadly it turns out we’ll have to wait for playback acceleration:

For now, the Subsurf modifier brings about the same performances than 2.79 (without OSD), at least for meshes deformed by armature modifier.
I don’t know about sculpts and multires.

About the bug tracker, I think it really deserves to be re-designed with simplicity in mind… It’s not easy to look for existing bugs.


I can see what you mean about the performance, for some reason the memory on 2.8 is 116 MB while in blender 2.79 it’s 15.7 MB. That’s a huge increase



As for topology tests…



Blue = 2.79, Red = 2.8


(Ace Dragon) #139

If you’re concerned about topology changes, keep in mind that OpenSubDiv does calculations in a somewhat different way than the custom subsurf code found in 2.7x.

Your creases should render far better for starters, though the issue with the value at 1 does look like something that can be reported.

(Piotr Adamowicz) #140

This kind of small issue is kind of pointless to even report while the house is on fire the performance has regressed all the way to unusability.

(cekuhnen) #141

Is it so bad?