Backburner Split Line supported GI methods?

[MegaPixel]

I was wondering if I wanted to use the Backburner to split my Large Vray renders up, which GI methods or combinations would allow me to do this without the precalculation that Irradiance maps require? (In which case I would use Distributed Rendering)

Would QMC/QMC be a possible scenario?


Thanks, Dave

[gilpo]

I've tried this a few times and have been dissatisfied with the results. There always seems to be a (somewhat) noticeable line where the strips line up. There appears to be a certain randomness to the GI solution accross computers.

To workaround this, I'll send out 2 backburner jobs. The first only goes to one computer and it just calc's the lighting solution. The second job is dependent on the first and it does the actual strip render.

Now, I will say I've never tried this with QMC/QMC, so I suppose with high enough settings to eliminate noise it would work, however the render time would be quite long. I usually use IM/QMC or QMC/LC for stills and pre-calc using the technique above.

I would be interested to hear others weigh in on this as well.

[MegaPixel]

My goal here is to improve production time on my exterior renderings which tend to be around 5000 pixels or so. I'll put up with DR for my Interior precalcs when using IM or LC, but I'm not so sure I need them for my exteriors. (I couldn't put up with DR for everything I do, I'd go insane) It would be nice to find a GI calc method where no matter how many machines participate in the rendering, they all will arrive at the same conclusion - thus allowing for split line rendering using backburner. if the render time goes up, that's fine - I'll just throw more machines at it through backburner.

Any other thoughts? Dave

[Morbid Angel]

well qmc/lc or qmc/qmc should be good. Since they all produce noise, and every machine, will do exect matching strips.

[MegaPixel]

Thanks Morbid - I'll try your suggestions this evening.

[Morbid Angel]

you may also try precalculating irmap on one machine then others will use it thus also produsing same solution.

[percydaman]

ya he already said he was looking for a solution that didn't require recalculating the irmap on a single machine.

[MegaPixel]

I don't think you're getting the "gist" of my original post. I'm trying to get away from precalculation in this case. I want to be able to fire a render job off and walk away without baby sitting the process. I don't have access to all the machines I need for precalc during the workday because other employees are using them, and if I wait until the end of the day to precalc, then I have to come back to the office later in the evening, save the precalced IR map after it finishes, then launch the backburner to wrap up the rest of the image. In which case, I might as well use DR and do both at once.

If you guys are telling me I have no choice other then DR, then so be it. I just wanted to know if there is another way is all.

Dave

[percydaman]

well there is a way actually. it involves precalcing the the irrad map on one machine through backburner and setting up a dependency for the actual render to be completed by your renderfarm. As long as your willing to do that, it only requires a few extra seconds to setup and should work just fine.

[MegaPixel]

Now that's interesting - I wasn't aware the backburner was inteligent enough to do something like that. Problem is, I don't think any one machine will be fast enough to precalc the entire large resolution IR map before the following morning when I come back to work

[Clifton Santiago]

With IR/QMC on exteriors you don't usually need to precalc. You can just assign the job and use "split scan lines". The only time you might notice banding is in very dark areas, which are usually minimal for exteriors unless you are doing a night shot.

For interiors I usually do IR/LC and precalcing is a must or you will get severe banding. It is very simple to do as percydaman described and calculate and save the IR and LC map on one machine, and then do strip renders dependent on the completion of the the saved IR/LC.