Terrible IPR Interactivity - Only with VFB?

[lospollos]

I am getting some serious interactivity/performance issues when trying to IPR using the VFB. Everything becomes incredibly sluggish, including simply navigating the viewport.

I've tried:
CUDA and CPU
Out of process IPR on and off
Distributed rendering on and off, including with and without the local machine (slave only)
ray bundle and rays per pixel set super low (32/1)
both legacy and viewport 2.0 (legacy is even worse)

The VFB is at default settings, no color corrections enabled, no LUTs.

There are no issues whatsoever using Maya's native render view, or using the V-Ray IPR viewport renderer. Everything is silky smooth and interactive.

This is using V-Ray 3.52.02 in Maya 2017 Update 3 + OpenGL -Core Profile (Compatibility), running on OpenSUSE Leap 42.2
Hardware: i7 6850k, 32GB RAM, Titan XP (up to date drivers)

Any suggestions or ideas? I'd really like to take advantage of some of the awesome VFB features but it's not even close to useable currently.

[lospollos]

Can't find a way to edit the initial post but I should also note this is true even for a simple scene with a ground plane and a sphere, two VRayMtls and 3 VRayLightRects, no GI. Render resolution is 1280x720, but the issue is still there until I drop to a much lower resolution like 640x480. Region rendering a small area inside the 1280x720 render has the same affect, the interactivity is perfectly fine.

Interestingly, the performance issues go away entirely if I set the active VFB channel to Alpha. However, when it's set to RGB color, the performance tanks again... making changes in the scene sometimes takes 2-3 seconds to even refresh the IPR, the camera and UI is sluggish, making selections has a significant delay, etc.

Again, if I set the VFB to Alpha, everything works smoothly, and changes in the scene refresh the IPR immediately, even though the beauty RGB is still being rendered in the background. I tested with some other render elements, and it seems that any geometry or matte elements (render ID, normals) don't affect the interactivity. Viewing any of the beauty render elements does slightly improve things over RGB color but it's still an issue.

I've also found the issue is much worse when using GPU (CUDA).

Anybody know why this is an issue only with the VFB?

[yavor.rubenov]

Hello,

Are you using any of the VFB color corrections ?

Best regards,
Yavor

[lospollos]

Hi Yavor,

There's no color corrections in the VFB, and no LUT. Also history is off.

I am using a global OCIO config, but having OCIO in the VFB enabled/disabled doesn't make any difference.

[yolov]

It could be worse with CUDA if you only have one GPU and it's used for both rendering and to draw the monitor. Could you try enabling "Low GPU Thread priority" for CUDA IPR (in the IPR tab under "advanced").
For the CPU - do you by any chance have the "track mouse" option enabled in the VFB?

[yolov]

Hi Yavor,

There's no color corrections in the VFB, and no LUT. Also history is off.

I am using a global OCIO config, but having OCIO in the VFB enabled/disabled doesn't make any difference.

Is the global OCIO config coming from Maya's settings?

[shaio]

Hello,
we know what the problem might be and will check it out. We'll update the thread when we have some more info or a solution.

[lospollos]

Hi guys,

Glad to hear you may have found the issue.

If it helps at all, I just did some more quick tests with OCIO. Disabling OCIO in the VFB fixes the problem. Maya's color management system is also using OCIO, but having it enabled/disabled doesn't seem to have any affect.

I'm using the latest spi-anim profile if that makes any difference, and it's defined "globally" by the OCIO environment variable.

Also yes, track mouse is disabled.

Thanks!

[alexanderdespotov]

Hello,

Finnaly we found the issue you have. The lag is significant in IPR with active OCIO color corections.
In tommorow's nightly build this problem should be resolved.
We still have some problems with "laggy" UI when OpenGL is used as rendering engine on NVidia graphic cards, and we will keep working on it.

Best regards,
Alex

[lospollos]

Hello,

Finnaly we found the issue you have. The lag is significant in IPR with active OCIO color corections.
In tommorow's nightly build this problem should be resolved.
We still have some problems with "laggy" UI when OpenGL is used as rendering engine on NVidia graphic cards, and we will keep working on it.

Best regards,
Alex

Great, glad it's fixed. I will test tomorrow once the nightly is available.

As for the laggy UI with OpenGL: Is there anything we can do in the meantime on Linux? I'm assuming the best solution currently would be to use the DirectX viewport, but that's only available on Windows.

Thanks

[lospollos]

I've also just noticed the all the VFB color control sliders are affected by having OCIO enabled too. Exposure for example, I can drag pretty freely with OCIO off and sRGB on. But with OCIO on its much slower.

Hoping the fix will address that too.

[lospollos]

Where can I find the nightly releases for Maya? I'm only able to find them for Blender at https://nightlies.chaosgroup.com/mai...est/2017-05-05.

Do I need a full license to access the Maya builds? I'm currently using a trial, but I'd like to be sure this is resolved before I commit to buying a license.

[yolov]

You can drop a line to support@chaosgroup.com and put a reference to this thread.

[lospollos]

Thanks Alex

[lospollos]

Tested the most recent "stable" and "nightly" available for Linux, and the issue persists

V-Ray for Maya version 3.52.03, revision 27400 from May 12 2017, 04:45:29
V-Ray core version is 3.52.03

V-Ray for Maya version 3.57.01, revision 27393 from May 10 2017, 05:36:29
V-Ray: V-Ray core version is 3.25.01

Do I need to be testing another version?

On a side note, I'm glad to see you're aware of the two others bugs I've run into:
VRayALSurface material does not work with LightSelect render elements
Subsurface Scattering in VRayMtl is not working

Hoping those will be fixed soon as well