“Nearly working” is worse than broken

[ricoholmes]

(A bit of a rant ensues..)


Hello there! Long time fan, and VRay evangelist, I’m afraid I have a bit of a rant to add here. And it’s all GPU based.


I was an early adopter of GPU since its first iterations, and the whole studio has become GPU only since. There’s a cleanliness to it that is appealing, and the speed of rendering of course is a dollar sign for the studio bosses.


BUT. What on earth is going on with the instability of the VRay Clipper ? You must be aware of the issues with it, as frankly it’s nothing new. We get that object mode isn’t functional in GPU modes (fine, that’s off the table) but how can you claim that it’s working at all? It has, time and time again cost us headaches and loss of time, endangering project deadlines to an incredibly stressful point.

Granted, it works to a degree (what, around 95% of the time?).. but when it doesn’t it’s disastrous as we’ve then put our faith in the method and there’s no sensible alternative at that point. When you’ve rendered a few thousand frames over a weekend spot and find that 50 to 100 frames are useless and all but 1 of your slaves have died to the point of hardware reset - it’s just not acceptable. Note: despite the “it might work” aspect of Clipper, those bugged frames can’t just be re-rendered on the lottery chance they might work “next time”.

Please don’t just pass this off or ask for a sample scene. You must be aware of the issues.

[savage309]

Sorry for the trouble. We are not aware. If you haven’t send a scene representing the problem, it is very likely we have unfortuantely missed it. Nobody has reported that yet.
If you can send a scene over, we will make sure to fix it ASAP (I am sorry, it really helps. We have proved that having a repro case really make us fixing it fast).
In the meantime, our QA team will try to reproduce that here.

Best,
Blago.

[ricoholmes]

Oh I do appreciate that. And I understand of course that it helps to have a scene to debug the exact problem. Client NDA means that we simply can't, though the 60+gb of alembic data required for the scenes means we can't just pop it over it you.

One of the reasons I personally get frustrated (it happens time and time again across studio projects btw) is that it's one of your ace cards against the competition.
The studio bosses have insisted we evaluate alternatives (octane etc) due to the issues.
Clipper and DistanceTex are your killer utility nodes and one of the few reasons I can justify we stick with Vray. As DistanceTex isn't available in GPU it would be nice at least to have Clipper working reliably as intended.

[savage309]

We will try to reproduce the problem here. We can sign NDA with you, if this will make it possible for you to share scenes with us. We really want to fix it.
If you think the NDA could work, please ping us.

Best,
Blago.

[yolov]

I'll need more details to understand what to look for.
When you say that some frames are 'useless', what exactly do you mean - what is the problem with those frames, if you could describe what happens visually in them, it will give a direction to my tests.
Also, any info on what's in the scene will be very helpful - what's animated? Is the the clipper? Is is the clipped object? Are they parented and animated? Are there any exclude lists used for the clipper? Any settings of objects/lights/clipper(s) that might be important?
Is this in max or maya?
Is this on windows or linux?
Is it a batch render?
With or without DR? What OS do the DR nodes run on?
Any info that might help us reproduce the problem is welcome.
Feel free to PM me with the details if you feel you can't share them here.

[ricoholmes]

Hi Yolov, and thank you for taking this one onboard.

I really do appreciate the frustration of having a bug report without a definitive scene to work from, so we're going to try and boil down one of the worst offenders this week and get something we can submit for your examination.

I understand you'll want to wait for that scene first, but if it's any help in the meantime:

Maya 2018.3 (we've seen the issue for a long time however)
Windows 10Pro
Standalone via VRScene export
No DR

Essentially, a few of the alembic files (Water Jet Hoses) are parented to a rotating head, the rest of the alembics are transform static.
I realise that's mostly useless to you, but as mentioned we're trying to find the time to boil a scene down to the offending components for you. Will email support with the appropriate material then.

My assumption was that because we've seen issues so regularly with clipper (on a wide variety pf projects) it was a known problem but put aside as a minor one.
Obviously that's not the case, so we'll do our best to help out rather than just complain

[yolov]

Yes, it's still too vague of a description, unfortunately. I did some tests before my first post and didn't find anything wrong off the bat, so I wanted to have more info before spending a lot of time on this.

In any case - do you use the clipper on the almebics (that's the impression I get)?
If yes, are the alembics imported as vray proxy or are they brought in with the maya alembic importer?
Again - it would be very helpful to know what the problem looks like? If you could send a few images (PM, email, ftp) or describe what the problem looks like, it's going to help me get to some conclusions.

[ricoholmes]

Hi Yolov, We're in luck!
A colleague was working on a simpler scene for another project ..and as soon as he added a clipper; problems started (!)
I've archived the scene as it's nice and small (no alembics etc). Will email it to support with you as attn

Hopefully there will be something of use to you there.

[yolov]

That would be very helpful. Please mention this thread's title or put a link to this thread in the email so we spot the email right away.

[ricoholmes]

Just a public update to say that Yolov and the ChaosGroup team are outstanding as usual.

The issue turned out to be problematic indeed, but I'm glad to report it seems perfectly stable and fixed in VRay NEXT. I simply haven't been able to break it so far. Yay you guys.

/RH