vray 6.2 Ornatrix + motion blur = huge preparation times

[simone_nastasi]

Hi,
trying to use motion blur with a character covered in ornatrix fur.

The difference between with or without motion blur is massive - and it's almost all in preparation time (transforming vertices, compiling scene).

Is it known/expected? Any hint to speed this up?

[hermit.crab]

Does it happen without the Ornatrix fur? To get a better idea of what's happening, it's best to send us the scene so we can look at it.

[simone_nastasi]

Does it happen without the Ornatrix fur? To get a better idea of what's happening, it's best to send us the scene so we can look at it.

It doesn't. Also, it takes some preparation time without motion blur, but wayyy less of it.
I'll ask for permission to send it or repro in another scene

[^Lele^]

It smells like excessive tessellation to me.
Verify you're not generating virtual triangles at rendertime (f.e. with the dynamic tessellation in the vrayOrnatrixMod) to too fine a size (that'll depend on hair count, lenght, and edge lenght. starting at 4px is generally good enough. then lower judiciously.).
See the docs about it here.

[simone_nastasi]

It smells like excessive tessellation to me.
Verify you're not generating virtual triangles at rendertime (f.e. with the dynamic tessellation in the vrayOrnatrixMod) to too fine a size (that'll depend on hair count, lenght, and edge lenght. starting at 4px is generally good enough. then lower judiciously.).
See the docs about it here.

Thanks Lele, I'll test without dynamic tesselation. It is set to 4px right now

[Joelaff]

Same thing here, very long prep times, esp since we need 10 subsamples for our bird wings. More motion blur samples = linearly slower.

[simone_nastasi]

It smells like excessive tessellation to me.
Verify you're not generating virtual triangles at rendertime (f.e. with the dynamic tessellation in the vrayOrnatrixMod) to too fine a size (that'll depend on hair count, lenght, and edge lenght. starting at 4px is generally good enough. then lower judiciously.).
See the docs about it here.

Hi Lele, I tried without dynamic tessellation, it wasn't that.
Weird thing: I tried a fresh scene, animated 3M hair on a sphere, tried to render with motion blur, and timings are way more reasonable. Tried vray 7 hotfix 1 too, same thing.

[^Lele^]

Hi Lele, I tried without dynamic tessellation, it wasn't that.
Weird thing: I tried a fresh scene, animated 3M hair on a sphere, tried to render with motion blur, and timings are way more reasonable. Tried vray 7 hotfix 1 too, same thing.

Right, so something else is afoot in your scene?
Or you think it could be 6.2 specifically?
We'd take a scene with reproducible part of the issue from you anytime, ofc.

[simone_nastasi]

Right, so something else is afoot in your scene?
Or you think it could be 6.2 specifically?
We'd take a scene with reproducible part of the issue from you anytime, ofc.

I'm really struggling trying to repro it on a fresh scene.
Where can I send the problematic scene?

[^Lele^]

Follow the instructions here.
Mention this thread, for support's reference.
It'll then go where it should, internally.

[simone_nastasi]

Follow the instructions here.
Mention this thread, for support's reference.
It'll then go where it should, internally.

thanks Lele - while preparing the scene I found the culprit.
The scene was using Corona cameras. They were renamed and I never noticed, but the stripped down scene worked perfectly, so I started merging stuff from the original one, and it was the camera.
Thanks again.

[^Lele^]

you're very welcome, glad it's sorted!

[Joelaff]

I am definitely using vray cameras in my scenes. For mine the slowdown is just that we are using 8-10 motion blur subsamples with feathers on a sub-frame sampled multi-gigabyte ABC for each shot in order to get the motion blur we want. Predictably slow, but necessary.