Major trouble trying to render with latest build

[tricky]

I hope someone can help - this is a bit of an epic.

We have recently upgraded to the latest build of Vray (from 1.09r). We have a lot of projects where the buildings are made of profiled metal cladding. Lovely blurry reflections of a HDR image - thats the theory anyway.

I haven't been able to produce a rendered image for the last two weeks because of "Unxpected Exceptions...".

I am trying to render 3960x2770 (which we have been doing for years). I have tried the Vray frame buffer, no buffer, save to vray image format, hyperthreading, 3GB switch, backburner render, local render, DR.....Our machines are dual Xeon 3.06GHz, 2GB RAM, XP SP2 etc.(i.e. pretty good!)

I have tried many many many options: here are my latest:


Here is a screen grab of the image as half of it was being rendered:


Here is a grab of the scene geometry - you can see from the inset it has under 100k polys - not many really:


And here's a shaded view to show the profile - I've put an autosmooth modifier on the editable mesh (all modelling done in AutoCAD):


The other problem is that the renders are taking the best part of a day to get as far as they do, so making 'quick' tests isn't as easy as it sounds. That is essentially what I have been doing for the last two weeks, and my client is losing his patience! I am happy for renders to take a day (that's why we have a renderfarm) so long as they work in the end.

As far as lighting goes, I have one sun casting Vray soft shadows. That and a pale blue environment. The HDR is used only for reflections.

All I get is a 'Unhandled exception....' whenever I use backburner, or a 3dsmax crash when I try locally. At a last attempt, I am *sure* it rendered at 1200 pixels accross (about 45 minutes IIRC), but I have tried so many things I can't remember if the settings were exactly the same.

[Morbid Angel]

tricky, never switch software in mid production. Its well known that migration between vray 1.09 and 1.47 is painful as they are very much different now. My advice to you if you want to meet your deadline is to revert back to vray 1.09 and finish your project, then start new one from scratch using new vray.
Reasons for your glossy reflecitons not working is becuase they have been modified significantly in new vray. So has many other settings which mean that you will have to pretty much redo and re setup your scenes etc.

[percydaman]

can you try attaching the entire building and creating a vray proxy of it, then retry rendering? Im just curious.


edit: what morbid says is true...you basically at least have to recreate all your materials...

[Morbid Angel]

another thing is that if you are trying to render in highres image I would not suggest using dr at this point. Try strip render, as that should work fine.
also what kind of exeptions are you getting?

[flipside]

I don't think he switched during this project. They just switched and this is a new project from scratch (i think )

Tricky, when do you get the exceptions? Ir map, lightmap, or while rendering?

[natty]

Hi

Why have you got your Face/Level coef set yo 2.5 ? .... this could be causing memory problems?..

[zoranm]

Tricky,

Could you elaborate a bit what sort of problems are they?
Does the crash happens always at the same bucket?

What I usually do:
Before anything else check that you don't have any "nul" objects (objects with no verteces) and that your sceene is not too far away from 0,0,0 point. I had in the past some issues with Vray in those circumstances.

1. Switch off all the lights. Switch on default lights. Apply Override mtl. to all object in the sceene. Switch off GI, Displacement, AA. This effectively eliminates materials, lights, reflections as a couse of crash.Render. If crashes, problem is with geometry. If everything is OK, go to 2.
2. Switch on lights and render. Crash or not?
3.Switch on GI.......and so on untill you find out where the crash is.

What I want to say is that you start with the bare bones sceene and than introduce more stuff into it untill you figure out what is the cause of the problem.

BTW, you can speed up your sceene a bit:
-reduce Hsph sub to10-15
-Noise treshlod=0.003
-Max.tre. depth 70, face/level coef=1
-Max.depth for reflections for metal=1 (you don't need in your case more than that)

Feeling your pain

Zoran

[jacksc02]

Switch your memory to dynamic and you should be ok.

[tricky]

OK, thanks for your responses: I'll respond one at a time.

Morbid Angel: we did not switch during production. These are new projects started with the new Vray build from scratch. I knoew that mid-project switches were a bad idea, and we have been putting off updating since, well, 1.09r become obsolete. This is a new scene from scratch.

Percy: I'll give that a go -never tried proxys yet, so I'll read up a bit first.

Morbid Angel: I may give strip render a go - I didn't realise DR could be problematic at high resolutions. I had hoped it wouldn't be problematic as we were hoping to go even higher res with our production work now that DR seemed fine. The exceptions are the type that don't illuminate the problem. This can be a real pain.

Flipside: Bingo! you are correct! As far as I can tell, the exception happens during the rendering process. I found this quite odd as I thought the RAM build up (if it were a memory issue) peaked during the calculation stage.

Natty: This came from the troubleshooting section of the help file: "(reduce Max. levels, increase Min. leaf size, increase Face/level coefficient, switch from Static to Dynamic Default Geometry)".

Zoranm: It is difficult to pin down exactly when the problem happens as the render takes so long to render. Typically, they are sent to our renderfarm and left going. We don't really monitor what is on the screen. Either that, or I have tried locally and left the machine overnight, only to come in and see that Max has crashed. I'll try your methods.

The thing that I am finding really difficult to deal with as that these renders take a long long time to render. To go through all this testing is gonna take heaps of time that I just don't have. Our scenes worked OK (bar quite grainy metals sometimes) in the older versions of Vray - it is only since updating that we have had the problems. Of course, we could revert back to the old version and start again with our current projects (about 10 plus schemes), but this would be a last resort. We NEED to be up to date as the gap will only grow larger.

[tricky]

Jacks02: I'll give that a go. If that is it I'll scream - I assumed Dynamic was only for things like displacement mapping or hair, not for static, pre-built geometry.

[flipside]

Yeah but still you can control ram usage very easily with it.

You don't get any warnings during LC or IR map calculation?

[jacksc02]

it generally is, but i have found it helps if your computer is crashing a lot.
Renders can be a little slower (sometimes a lot) but it will render in the end.

start with the default 400mb and incrementally increase it under you cant render.

[tricky]

I'll look into Dynamic immediately.
No warnings during LC or IR.
Only warning I see (which I generally ignore) is "warning: Scene bounding boxis too large, possible raycast errors", but I thought this only affected the accuracy of geometry at a massive distance from 0,0 my a unit or so, if that. We always model and work in millimeters (to comply more easily with architects), but we have started thinking about doing an autoconversion from ADT into MAX so that we are in meters in MAX.

[tricky]

I've just tried using Dynamic - and I'm watching the RAM useage. Even when assigning, say 800MB, it only seems to be actually using a peak of around 530MB. Does this mean that my scene doesn't need any more memory to render, or does it mean that large ammounts of RAM only get used whilst actually rendering?

[jacksc02]

what are you settings for the dynamic memory?