single frame distributed rendering

[dancmacarie]

Hi,

i am looking at possibly getting v-ray and i would like to know a bit more
about single frame distributed rendering for high rez work
can you split a frame to a render farm from within v-ray without using max split render ?
in other words can you get immediate feedback from network cpu's that go and render bits of the frame ? like banshee for brazil promises to do

Thanks

[casewolf]

yes, simply do a search in this forum using distributed rendering as keywords and stumble over many posts regarding this.

[cgrant3d]

Things to know before using Distributed Rendering...

Technically, DR (distributed rendering) works but there are some things to keep in mind, especially if you are spoiled by backburner...

1. DR currently works only with the beta version of vray. As of today, the current beta is 1.46.08 with the final version being 1.5. Thus, it's getting close to the final rev, but it's not without its faults... The key is to expect problems , small or large, and don't be surprised when something goes wrong - it's BETA.

2. The vray spawner (equivalent to backburner server) must be restarted a lot. A lot. Just do yourself a favor and expect it and you'll be fine.

3. Don't hit cancel. The max pause/cancel buttons that appear after you hit render. Those are mystery buttons. I think they work like this: every other time you click cancel vray (much like max used to do) decides you've spent too much time working on your project and you should take a break, thus quickly crashing max regardless if you saved recently or not.

4. DR is awesome. It's enabled me to render things across several stations that I would have needed an entire weekend to process on one computer.

5. The host computer (the one you're working on) MUST participate in the DR process. So, in the middle of the day when you hit render you have to wait to use your computer until the DR is done. Works great for previews. Great. BUT if you have a hi-res print due at 5pm don't expect to use your computer much while it is rendering. Vray does a great job of using every CPU cycle available, unlike the MAX Scanline renderer, whose inefficiencies make it easy to keep on doing photoshop work / light max stuff even while rendering...

6. Your VRay license is tied up while waiting for DR to finish. Don't expect that you can switch to another workstation and work on your project while a render is going. Not going to happen. Vray uses a network license server, when DR is going, that license is used up. You could buy another license of course though. In which case this problem isn't a problem at all...

7. DR is absolutely unbelievable. I use it every day. When I have to use the scanline and can't use DR, it just seems so wasteful...

8. Don't get any ideas about backburning your DR render so you can work on your workstation... It would be a great idea if it worked. But no. So, I repeat, when you start a DR, your license is tied up. There isn't some slick way to bypass it... You'll have to wait it out.

9. There is no way to change / schedule DR renders. The computers that are available to render when you hit render are the ones that render. They don't automatically join if you start them after the render has started. You can't remove them (although truth be told I never tried manually killing one with task manager because I've never had a project that I could risk it)

10. If you successfully hit cancel and nothing crashes, you must wait for the currently rendering buckets to finish. So, if you set up the render as super duper high quality uber cool, you might wait half an hour or whatever for all the rendering buckets to finish before you cancel. Or, you could kill the process with task manager, restart all your vray spawners / 3dsmax.exe processes on your rendering stations and reload your max file... Unless your farm is huge you can probably do all that before vray would otherwise have finished. It's what I do everyday nearly. Annoying but it's offset by #11.

11. Distributed Rendering, IMHO, is the best thing as a max user that I've ever seen. I know it's not technically "new" as other renderers have had it, but for those of us who waited and waited before selecting a 3rd party renderer, it's absolutely indispensible!

SUMMARY: Get Vray. Play with it, get comfortable with it. It's very different from scanline. Set up DR, it's pretty easy to do. Play with it, get comfortable with it. IT'S WORTH IT.

Christopher Grant
3D Artist, Fleetwood
Webmaster, ScriptSpot

[dancmacarie]

Thank’s Christopher

That’s really useful and interesting, of great use to me, because I never used v-ray.
I do architectural visualisation and hi rez and hi poly slow rendering are the usual problems
So having a system where you can chuck hardware at , and you can use network cpus to do your setup work is what I want.
At the moment I use pure cards with renderpipe that do exctly that but they are quite expensive I cant afford to many.

Cheers

Dan

[dbuchhofer]

9. There is no way to change / schedule DR renders. The computers that are available to render when you hit render are the ones that render. They don't automatically join if you start them after the render has started. You can't remove them (although truth be told I never tried manually killing one with task manager because I've never had a project that I could risk it)

Don't kill a vrayspawner... you end up screwing the render over.. there isn't any timeouts or failsafes currently. you end up with a bucket that never finishes on your render, have to cancel the DR, and at times have to restart max.

I've only had crashes on smaller images so far.. I don't know that i'd trust dr as my only means of relying on a render when i can't be back to check on it occasionally.. right now i'm sending to backburner also on longtime renders.. that way if theres a problem with one, the other works out. not everyone has that kind of computer resources though

Nice to see you around Chris, excellent site in scriptspot, Thanks.

[cgrant3d]

Aha! I figured killing a spawner would result in bad stuff... I've had a individual computer give a vray assertion error during a late night render, only to come in and find that the last bucket that computer was rendering was unfinished leaving a huge gaping black square in my image... Sounds like basically the same thing you're talking about, only I didn't deliberately kill the spawner!

Hopefully, the vray crew will be able to get in some safeguards to prevent problems with DR in the future...

Oh, and thanks for the kind words regarding ScriptSpot... It's always nice to hear!

Christopher Grant
3D Artist, Fleetwood
Maxscript Addict, ScriptSpot

[quote="dbuchhofer"]

9. There is no way to change / schedule DR renders. The computers that are available to render when you hit render are the ones that render. They don't automatically join if you start them after the render has started. You can't remove them (although truth be told I never tried manually killing one with task manager because I've never had a project that I could risk it)

Don't kill a vrayspawner... you end up screwing the render over.. there isn't any timeouts or failsafes currently. you end up with a bucket that never finishes on your render, have to cancel the DR, and at times have to restart max.

I've only had crashes on smaller images so far.. I don't know that i'd trust dr as my only means of relying on a render when i can't be back to check on it occasionally.. right now i'm sending to backburner also on longtime renders.. that way if theres a problem with one, the other works out. not everyone has that kind of computer resources though

Nice to see you around Chris, excellent site in scriptspot, Thanks.

[dancmacarie]

so one could work on 10 machines to setup the scene with DR for speed , and then do the final render on the same 10 machines or more using max's backburner split frame renderer for reliability.
Is this feasible ?

[dbuchhofer]

True.. good point

but only really if you either render in Bucket mode.. (Irradiance map for each bucket is calculated individually) or if you have a previously saved irradiance map.. Otherwise, the irradiance is calculated for the WHOLE IMAGE and it only renders the strip...

^^ Thats the reason why everyone dislikes the render strips, you essentially need to do the irradiance on one machine prior to render, or you need to have settings set to fairly high to prevent having discoloration between various buckets in bucket irradiance mode..

Currently you can't (At least, its failed when i tried..) save an irradiance map that was created using DR.. one of its larger limitations that i don't quite understand why

[dancmacarie]

but only really if you either render in Bucket mode.. (Irradiance map for each bucket is calculated individually)

please excuse my ignorance, i am just starting to try out v-ray free, what is
bucket mode, that's not direct computation ?

[ShaunDon]

Bucket mode means the irradiance map is calculated individually by each render bucket (those little square boxes that represent each proc's working are when you render). To use DR, you must render to bucket mode or be using a saved & shared IR map that you've already calculated -- but that doesn't make sense most of the time since IR calculation on high-resolution images is the most time-consuming portion of the render.

The drawback is you have to set your IR settings higher, otherwise if it isn't precise enough you'll see IR differences in the border of one bucket region to another.

Shaun

[crazy homeless guy]

so can i use backburner to send a irradiance map calculation to a machine, and have that calculation be a distributed render? ...i tried it, and it did not seem to work, but i want to know if it just doesn't work, or if i just have somethign set wrong.

[czoog]

so can i use backburner to send a irradiance map calculation to a machine, and have that calculation be a distributed render? ...i tried it, and it did not seem to work, but i want to know if it just doesn't work, or if i just have somethign set wrong.

nope, it doesn't work.

[ShaunDon]

Must be something with the new vray if you can't get it to work -- we do that sort of thing all the time here. If you set it to calculate single frame and save the VR map and have DR disabled, we've had no problem farming it out to a specific node and letting it do the work.

Shaun

[ShaunDon]

Now I feel like an idiot that I just read Vlado's sticky... are you using Max 7?

"Auto-saving of irradiance maps through backburner DOES NOT WORK in 3dsmax 7. The problem seems to be in the backburner plugin for 3dsmax 7 which terminates the 3dsmax 7 before VRay can write the maps to disk. We have notified the discreet for the problem and are waiting for a response."

Shaun

[crazy homeless guy]

Now I feel like an idiot that I just read Vlado's sticky... are you using Max 7?

"Auto-saving of irradiance maps through backburner DOES NOT WORK in 3dsmax 7. The problem seems to be in the backburner plugin for 3dsmax 7 which terminates the 3dsmax 7 before VRay can write the maps to disk. We have notified the discreet for the problem and are waiting for a response."

Shaun

yes, i am using Max 7, and the latest build of Vray. in reference to you message above the one i quoted, i was trying to do a backburner single frame render, with DR enabled. the machine running the server picked up the job, and rendered it, but didn't connect the other computers to it to render it using DR. it labeled the local processor properly (0.0.0.0), but didn't find others.