Slow Lens Effects updates with high-res images

[Alex_M]

I usually have to output final images in the rage of 4000-4500 px width/height. With such image resolutions I'm having very hard time working with Lens Effects because of the slow update speed even with turned hardware acceleration on. I'm getting update speeds of no less than 20-30 seconds every time I change any parameter. Is there a trick that allows faster updates with larger images or is my GPU just too old or slow for hardware accelerated lens effects? If I buy 2x GTX 1080 would the lens effects be faster? I'm using Vray 3.50.03.

[savage309]

There should be some messages about the lens effects (how long they took, which devices they used, etc) in the V-Ray log. Can you share it ?

Best,
Blago.

[kosso_olli]

It is the same here. I am kind of used to it, because in the old versions it took even longer.
Thing is, it gets much slower when the intensity mask is turned on. Will try to get the statistics.

[Alex_M]

I don't see statistics in the log window when I update the lens effects. Do I need to render the image for the statistics to show?

PS: Nevermind, I rendered the image again. The log shows that glare took 33.4 sec. to calculate on this image (4000 x 3000 px). Please see attached.

[savage309]

Any idea how long it takes on the same image without hardware acceleration (you can turn it off from the VFB).

Best,
Blago.

[thanulee]

Have to confirm here as well, that lens effect takes a while. It actually doesnt seem very responsive after a while. I had a car with a tent (pretty basic scene) and at the beginning the lens was kinda real time, but after a while it started lagging more and more. Dont have the scene anymore, it was a test i was doing in beta but never opened a thread about it. cheers

ps. 1080p here

[Alex_M]

Any idea how long it takes on the same image without hardware acceleration (you can turn it off from the VFB).

Best,
Blago.

I did a new test with the same scene and this time I used a stopwatch as I didn't want to rerender such high-res image every time I want to see how long lens effects took (Clicking on "Update effects" doesn't update the log). I measured that using hardware acceleration took 37 seconds and not using it took 24 seconds - 55% faster! Shouldn't hardware acceleration decrease calculation times instead of substantially increasing them? So obviously there's something wrong either with my GPU, drivers or Vray.

I'm going to convert the scene to corona and test the lens effects in there for speed comparison.

PS: On average corona updates take 18-19 sec. with the same scene and resolution, with both bloom and glare turned on, and set to look similar to the vray render.

[savage309]

For this setup hardware accelerate should definitely be (much) faster than CPU. Will test with same resolution and hardware and will update you if we can reproduce that (if we can, we will fix it).
What is your driver version ?

Best,
Blago.

[Alex_M]

Thanks, hopefully it's something easy to pinpoint. My drivers are 376.33 WHQL. I should put this in my signature.

[LudvikKoutny]

Do you use intensity mask by any chance? I seem to get about 50% slowdown of LensFX generation when I enable intensity mask.

[Alex_M]

Yes, I do use it. Unfortunately I don't ever completely disable it because the whole image becomes blurry/hazy.

[savage309]

Can you try with smaller resolution ?

With resolutions ~4k you need a bit more than 3.5 GB memory and GTX 970 is the only GPU (that we know of) that has a hardware limitation when using more than certain amount of memory (3.5GB) making it much slower. Check here for more information.

Thanks,
Best,
Blago.

[Alex_M]

Yes, smaller resolutions seem to update faster with GPU compared to CPU. By the way, I'm using GTX 980, not 970 (check signature). Does it have the same problem? I'm overdue for a GPU upgrade, if I get something like GTX 1080 would there be slowdowns with images of similar resolution?

[Vizioen]

Yes, smaller resolutions seem to update faster with GPU compared to CPU. By the way, I'm using GTX 980, not 970 (check signature). Does it have the same problem? I'm overdue for a GPU upgrade, if I get something like GTX 1080 would there be slowdowns with images of similar resolution?

Lol if you're overdue for a GPU upgrade than I'm waaaay overdue (quadro K4000)

[savage309]

Yes, smaller resolutions seem to update faster with GPU compared to CPU. By the way, I'm using GTX 980, not 970 (check signature). Does it have the same problem? I'm overdue for a GPU upgrade, if I get something like GTX 1080 would there be slowdowns with images of similar resolution?

Nope, it is something else in that case. Both K4000 and 980 should be much faster than CPU.
Here it seems to work fine so far.
@Alex_m - scene should not matter for this, but just in case, can you send it so we can check it as well ?

Thanks,
Best,
Blago.