[Radiance-general] Fwd: strange artifacts in rendering

[Gregory J. Ward]

Just forwarding this to the mailing list in case as an additional warning against installing Mac OS X Yosemite (10.10.x).  As if the multi-processing bug were not enough, there seem to be other problems with instances and/or textures (not sure) on that platform.

I may try investigating this on the weekend, but I don't hold out much hope for a resolution.

-Greg

Begin forwarded message:

> From: Minjung Kim <mkim85 at gmail.com>
> Subject: Re: [Radiance-general] strange artifacts in rendering
> Date: August 19, 2015 4:58:24 PM PDT
> To: "Gregory J. Ward" <gregoryjward at gmail.com>
> 
> Hi Greg,
> 
> I think the problem might indeed be with OS 10.10. None of the 20 scenes that I rendered on OS 10.9 had any issues, whereas more than half of the 20 on OS 10.10 did. Please see attached files for examples. 
> 
> Thanks for your help!
> 
> MJ
> 
> On Wed, Aug 19, 2015 at 4:33 PM, Minjung Kim <mkim85 at gmail.com> wrote:
> I'm going to render a bunch of other blobby objects on 10.9, and see if I get the problem here. I'll let you know what I find out. 
> 
> Thanks!
> 
> MJ
> 
> 
> On Wed, Aug 19, 2015 at 4:30 PM, Gregory J. Ward <gregoryjward at gmail.com> wrote:
> Thanks, Minjung.  
> 
> I guess we can add this to the list of bugs under Mac OS X 10.10, which to me has been a disastrous release.  I seriously doubt I will be able to fix problems on this platform, but I'll give it a try when I have some time.
> 
> Cheers,
> -Greg
> 
>> From: Minjung Kim <mkim85 at gmail.com>
>> Subject: Re: [Radiance-general] strange artifacts in rendering
>> Date: August 19, 2015 4:16:50 PM EDT
>> 
>> Hi Greg,
>> 
>> Thanks for your help! I am still unable to get the artifacts to come back -- but only on my current machine (late-2013 iMac, 21.5 in., OS X 10.9). If I run the same code on a different machine (late-2013 iMac, 21.5 in., OS X 10.10), I reliably get the artifact. Isn't that strange?
>> 
>> Attached are the files that I used. To run, please use the following commands:
>> 
>> oconv square.rad > square.oct
>> oconv scene.rad > scene.oct
>> rpict -x 1024 -y 1024 -vh 12.018 -vv 12.018 -vp 0 -0.57 0 -vd 0 1 0 -vu 0 0 1 -av 0 0 0 -vtv -ab 1 scene.oct > scene.pic
>> pfilt -1 -x 512 -y 512 -e 1 -r 0.6 scene.pic > scene.hdr
>> 
>> In scene.rad, the square is incorporated as an instance. I know that I don't really need to instance the square since I only have one, but the scene with the artifacts was using instances, so I thought it would be better to send you the code as is. 
>> 
>> If anything is unclear, please let me know. Thanks again!
>> 
>> Regards,
>> 
>> MJ
>> 
>> On Tue, Aug 18, 2015 at 7:00 PM, Minjung Kim <mkim85 at gmail.com> wrote:
>> Hi Greg,
>> 
>> Thanks! I'm putting together the files, but I'm unable to replicate the problem using my latest code, though I don't think I've changed anything substantial. I'll get back to you once I can reliably replicate the artifacts.
>> 
>> MJ
>> 
>> On Mon, Aug 17, 2015 at 9:04 PM, Greg Ward <gregoryjward at gmail.com> wrote:
>> Hi MJ,
>> 
>> Can you send me your model & rendering parameters off-list.  I won't know what's going on until I play with it.
>> 
>> Thanks,
>> -Greg
>> 
>>> From: Minjung Kim <mkim85 at gmail.com>
>>> Subject: [Radiance-general] strange artifacts in rendering
>>> Date: August 17, 2015 5:30:37 PM EDT
>>> 
>>> Hi everyone,
>>> 
>>> I am getting strange artifacts in my renderings, and am wondering which parameters to tweak in order to get rid of them. The artifacts look like a white, or sometimes half-black and half-white, patch at random locations. See below for examples:
>>> 
>>> http://minjung.ca/tmp/artifacts1.png
>>> http://minjung.ca/tmp/artifacts2.png
>>> 
>>> I've tried (1) setting ad = 4096, as = 1024, and (2) setting aa = 0, ar = 0, but neither of these two settings fixed the problem. Do you have any idea what might be happening? Here are some possibly relevant factors: 
>>> 
>>> - The object is completely Lambertian.
>>> - The only light source in the scene is a glow source that is positioned behind the camera, and covers as much of the sky as possible. 
>>> - I don't think I've ever encountered such artifacts with untextured stimuli.  I could be wrong, though.
>>> 
>>> Thanks in advance!
>>> 
>>> MJ
> 
> 

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