Rendering with Rebus

[timkirkhope]

Hi Corona peeps,

I'm currently having a heated discussion with Rebus, I have run 20+ jobs with them recently, all similar scenes, all with exactly the same settings and resolution. All renders came out perfect except for the last one, which had been rendered before on rebus but with a minor geometric alteration, but this time the render came out incomplete, it had not finished the initial pass although they had charged me the full price.  I contacted them and they claim that the image (thumbnail) attached below is actually 25 passes, even though it has not even completed the alpha/wirecolour. 

I was hoping to get an official word from someone at Corona claiming whether or not these images below could possibly be 25 passes.

My week was going so well before this (what a nightmare)

Hope you can set the record straight!!

[Ondra]

Hi,
I really do not want to get caught in the middle of this.

But: alpha/wire pass never has noise. It may have black pixels. If there is noise in it, it probably means it was created by merging multiple images with black pixels, meaning the input images did not have at least 1 pass finished.

BUT if you compose multiple less-than-1-pass images, you will get better quality result (although slightly darker than it should be). So if for example 30 machines render almost-finished 1 pass, and you merge, you may get 25-passes quality equivalent.

So in the end it is plausible that you got the rendering time you paid for, even though the result has problems. There should probably be a check that makes sure each image renders for at least 1 pass, but that would either mean you would have to wait longer (25 image could be distributed only to 25 machines), or some extra steps would be needed (rendering in stripes)

[timkirkhope]

Thanks Keymster, that's exactly what has happened. I accessed one of the passes and it had large areas of black so when you combine it you get noise.

On Rebus or Corona I never thought you had the choice of setting a rendering time for each pass.  When you launch rebus via the manager its either max render points or max passes (whatever comes first) so you would think that a single pass would be achieved, not multiple partial passes.  At least I have not seen this option...

[Rebus farm]

we fixed the matter (i guess)
In case the time limit is to low the rendernode cant completed a full pass
that cause black pixel in the render - the image merge combine the black pixel to another non black pixel and that leads to incorrect results
we now simply ignore black pixels - it give better results but in theory it can happen the merged image contain black pixels since no rendernode hit that specific pixels ...

[Ondra]

I wouldnt worry too much about it. If you render with 50 machines, each one finishes half a pass, and you merge to get 25 passes quality, the probability that no machine will render any specific pixel should be 1 to 1125899906842624. So approximately 1 in each 10 000 000 renders in 10k resolution should have a black pixel with these parameters.

[timkirkhope]

Thats Good to hear, thanks for sorting this out! Much relief :)

[Rebus farm]

I wouldnt worry too much about it. If you render with 50 machines, each one finishes half a pass, and you merge to get 25 passes quality, the probability that no machine will render any specific pixel should be 1 to 1125899906842624. So approximately 1 in each 10 000 000 renders in 10k resolution should have a black pixel with these parameters.

but in case each node complete just 50 pixel out of 3000 I have 50px*50nodes=2500 pixels only
i doubt that will happen somewhen but it can happen at least :-p

anyway ...