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Dark channels in blow up render

Posted: Wed Aug 25, 2010 3:34 pm
by JorisMX
Anyone have this happen before? Z-Depth and Alpha's lightest color is a 128 Grey value instead of 256.
I applied the default material and changed illum (although this shouldnt change anything) to sky dome white.

Re: greyed out Alpha Channel

Posted: Wed Aug 25, 2010 8:44 pm
by zdeno
network cooperative mode ? or single render ?

Re: greyed out Alpha Channel

Posted: Thu Aug 26, 2010 12:32 pm
by JorisMX
single render from studio

Re: greyed out Alpha Channel

Posted: Thu Aug 26, 2010 12:57 pm
by tom
Could you please post these outputs you're talking about?

Re: greyed out Alpha Channel

Posted: Thu Aug 26, 2010 3:08 pm
by choo-chee
perhaps your camera is located behind an emitter or a glass wall?

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 5:49 pm
by fuso
Hi guys,

Whilst being on that topic, is that issue with having a greyed out alpha in cooperative mode
fixed in the new release? I am just about to do a clean sweep and to upgrade to the latest,
but needing that feature to work. Can someone please enlighten me on that?

Cheers,

J

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 5:54 pm
by tom
Once if we can see what is "greyed out alpha" we can fix... :idea:

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 6:23 pm
by fuso
tom wrote:Once if we can see what is "greyed out alpha" we can fix... :idea:
Hi Tom, surely it cannot be just us two having had this problem. Every time I send a job
to render in cooperative mode I end up with an alpha mask which is 100% black where
you have 100% transparency or simply no objects. But the areas where you have 100%
opacity aren't 100% white as they're supposed to be, they are a medium grey. Therefore
the file becomes useless for postproduction unless you go through the pain of fixing the
alpha channel output. I thought this was a well known issue... Hope the problem is clear
now or do we still have to post a picture?

Thanks for looking into this Tom.

J

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 6:25 pm
by tom
No, I cannot reproduce this. A simple MXS having this issue will make everything faster.

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 6:33 pm
by fuso
Maybe I should point out again that it's doesn't seem to be an issue with the actual mxs file,
as it doesn't happen when you send the very same file to render locally on a single node. It
appears to become a problem when merging the alpha output between the clients, therefore
it's not really possible to post a file where the problem appears. I wouldn't have one handy
now anyway. I am also aware that my problem appears to be of a slightly different nature.
So I guess JorisMX should post his mxs. But according to zdeno's response he seems to have
a clue...?

Re: greyed out Alpha Channel

Posted: Thu Sep 02, 2010 7:23 pm
by tom
fuso wrote:So I guess JorisMX should post his mxs.
Indeed.

Re: greyed out Alpha Channel

Posted: Wed Sep 08, 2010 11:06 am
by RobMitchell
Just to chime in here, I've also been getting gray alphas as opposed to white. It's not been a huge problem for me personally as I have some decent masking software, but I could see it being a problem otherwise.

Re: greyed out Alpha Channel

Posted: Wed Sep 08, 2010 11:08 am
by tom
I wish one of you send a simple scene with this behavior so we can fix.

Re: greyed out Alpha Channel

Posted: Wed Sep 08, 2010 11:19 am
by RobMitchell
Hi Tom, been a bit busy with some jobs at the moment (only just had time to post in here :)) but will try and get an example over to you soon.

Re: greyed out Alpha Channel

Posted: Wed Sep 08, 2010 11:57 am
by RobMitchell
I quickly took the time to upload a file that has demonstrates this issue. It's a small part stripped out of a much larger assembly model, sky and general settings have been set to default to make it a bit easier to work with.

http://www.sendspace.com/file/inrapu

(download link is below those annoying flash ads.)

So, for me, this generates a grey alpha channel. Like I said it's not really been a problem personally, but thought I'd put some input into to this.