black render....

[skogskalle]

Hi guys!

weird problem... working on an exterior at the moment. It renders fine at 640x480, 800x600 and 2000x1500 pixels, but when I go higher it just dont render at all. And no, its not a memory problem... it doesnt hang or crash or anything, it goes through the lightcache pass, the IRR-map passes and renders... but everything shows up as black. (or nothing shows up at all, take your pick) I have "show calc. phase" ticked on both lightcache and IRRmap, and everything looks fine on lower resolutions... but its all black when I go higher than 2500 or so.

any ideas? The deadline is wednesday morning and I really have to start rendering today to be able to make it...

[Morbid Angel]

well it is a memory problem. Are you rendering with vray vfb? are you rendering with dr?
I got that when rendering with dr...there was some kind of memory leak problem.
Solution may be try to render to vray image then convert.
Or render strips, since each strip would be the 10th of the size it mght work. But you need to precalc the irmap and lc before doing that.

[skogskalle]

thanks for the fast reply, Morbid.

Im not using dr, but I am rendering to vray vfb.

this is even more strange... I tried to render at 2000x1500, it worked fine. Then tried 2500x1875 - everything black. tried 2499x1874 - it renderd fine. Tried 2500x1875 again and this time it seems to be working... que?

So at the moment, I think the problem is gone.... but if it appears again Ill try to render to vray image as you suggested...

if this is a memory leak problem, do you know if its fixed in newer vray versions?

thanks again
Kalle

[Morbid Angel]

yes...recently i've rendered as large as 4k film and it was no problem...but, it was a problem if i rendered in max, the buffer showed as noisy multicolored image...but when i did network render it was ok, talking to vlado he explained that this is memory related, especially when you have gbuffers in there, which means that you have not 1 but nth number of large images stored at once in the memory.

[skogskalle]

ok...
I though it might have something to do with the "secondary ray bias" setting... I normally always have it at 0 or very close to 0... but in this case I had to put it alot higher to get rid of some double faces showing up as black splotches. (i got the 3d model from the client and its horrible)... other than that I havent used any special settings on this project at all... so I was quite surprised when it just didnt want to render...

would setting the secondary ray bias higher make Vray use more memory?

or is this memory leak just something that happens for no reason at all from time to time? (I didnt use any gbuffers now... hardly even know what that means

[Morbid Angel]

raybias shouldnt make renders go black...I dont know...need to experement.

[skogskalle]

the first render came out OK... but when I tried to render a second view from the same scene the problem came back. I restarted max, and tried again and now it worked... which seems supports your memory-theory...
the funny thing is,when I first tried to render the second view (and it failed) I checked how much memory max/vray was using and it never went above 900 Mb. My computer has 2 gigs so there shouldnt be a problem???

anyways... thanks for taking your time to help me, and if you figure out what the problem is, please let me know!

[Morbid Angel]

may want to try 3 gb switch if you havent done so yet.