DR output, bucket mode questions

[gustojunk]

I want to test DR on a renderfarm using 10 dual CPUs. I want to send them a test image before next week I send images for final output.

The image output size in this test is 3000x2250 (final output would be more like 12000x9000) , below are my settings:






Here are my questions:

1.What is the best bucket size for this case?
2. Where do I set that up? Render Region division?
3. Am I going to have problems seeing seems between each bucket? (if so, what settings in the Irradiance Map would prevent this?)


Thanks for the help,

Gustavo

[Long John]

a bit off topic but for what do you need such a big size?

please don´t say printing.

[gustojunk]

well, printing is obviously the straight answer. Now in more detail I can tell you these are renderings of product design concepts in full size, the products are about waistline tall (cannot say more for NDA restrictions). So the images are poster size. Output will be Iris prints @200 dpi.

[arobbert]

I have found the only way to do this is to calculate the radiance map first on one machine, save it and then use the pre-calculated map to bucket render the image on the render farm. This is a work-around, hopefully we will see bucket calculated radiance maps that blend seamlessly for Vray in the near future. I understand there are now other products that can do this. This is on the top of my list for Vray features.

[gustojunk]

Well this sad news for me. I have more shots to be rendered at highrez that time to compute Irradiance Maps by a single machine. So I guess I'll have to figure something else out.

I really look forward to a better implementation of irradiance maps for farms. BTW for rendering passes the new 'network render region' feature in max 6 (using backburner) works great! for the rendering pass only thought. But the beauty of that is that you can use as many machines as you want for a single frame instead of being limited to 10 machines like in DR.

Maybe making Vray work-in the irradiance map calculations with this feature would be a nice solution. Currently each node redundantly calculates the entire map, and then it splits the last render pass in horizontal strips (one per machine)

Thanks for the feedback Arobert,

Gustavo

[nully]

thats a good feature didnt know about it, took me a while to find i though its actually called 'strips' in the netrender options - is the final image exactly the same as it would be on single machine - havent had chance to see the final result of an image i sent to net render

[gustojunk]

is the final image exactly the same as it would be on single machine

yeap, as far as I can tell. The farm sent me a Jpeg preview and looked perfect. Now the only problem is that all the machines calculated the complete irrad. map. They have exact machines I believe, otherwise could have been differences.

I really, really expect the irradiance map bucket issue to be fixed, that means amazing possibilities to render everything under the sun in a matter of minutes. Followed by a fat farm invoice that is

[nully]

I did a test using direct computation - works perfectly.

[gustojunk]

sorry for the dumb question, but I'm really new with Vray, what's direct computation? can you get the same relust as with irradiance map passes?

[nully]

quoted from the vray help file

' VRay implements two methods for computing global illumination - Direct computation and Irradiance map. While direct computation is a simple algorithm that traces all rays needed to compute the GI, it produces most accurate results, however at the price of longer rendering times. Irradiance map is an algorithm that uses sophisticated caching techniques and produces less accurate results with better rendering times.. '

it takes longer with high subdivision - so its a prime candidate for Network rendering.

[gustojunk]

Thanks Nully, I read in the manual too, but I was hoping to get the 'gossip' about it. Like what's a good Subdiv. number to work with, etc.

I run a rendering last night using direct computation with 50 subdivision (the default number), everything else same settings that my post above (3000x2250 rez) and this morning, 12 hours after, it was still going! based on how many tiles are completed I expect it to run for about 20h total or more!

BTW using the Irradiance maps settings also posted here, instead of direct computation, the same scene took only 1h 53m.

What would be a good subdiv number so I can get similar quality than with my irrad map settings but render times more bearable, Ideally no more than douoble that using IM passes ?

[dbuchhofer]

First question is.. If you have to render ~8 or more images.. use 10 machines and normal net render

Personally I would suggest to ignore the direct comp for now.. Its basic brute force rendering.. and in most scenes needs high enough subdivisions to be prohibitively slow to get rid of the noise.. the exception being scenes with already generally noisy textures

At the irradiance settings you have.. (depending on the scene really.. but thats pretty damn high) you shouldn't have much problem with seams in bucket mode.. since when in bucket mode there is some overlap between adjacent buckets to help smooth out the lighting.. If you do get seams, you can turn up the gi max rate to 0.. that should totally eliminate them.. but will add a lot of calc time to the irradiance map..

[nully]

after more messing with net region render aka strips Ive come to the conclusion its only really useful if you have lots of machines in the farm, no matter what settings i enterd for strip size and render region size (in vray) I got a huge overlap , ( thats with the overlap paremeter at 0 and 1 ) so unless im doing something wrong (its possible ) then id only use this if you have lots of machines.

[gustojunk]

thanks dbuchhofer, I'll try DR in bucket mode with max. rate up to zero and see what happens. Your answer conflicts with what others have said about seams being visible between buckets no matter what. But I guess I need to test it and find out what really happens.

Nully, I'm not familiar with 'stripping' myself , I still have Max 5 here, The farm I'm trying to use has Max 6, they run the image on 10 machines and there was not overlap from what I can tell seeing a screenshot of their setup, 10 little windows with a rendered strip each, I think it was a screenshot from backburner.

[nully]

yeah its backburner - the final image is perfect but during rendering theres always overlap..