Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] Bug Reporting => [C4D] Resolved Bugs => Topic started by: dolain on 2017-07-18, 13:56:12

Title: Clipped EXR output
Post by: dolain on 2017-07-18, 13:56:12

Hi there
I'm not yet sure about the cause of this behavior (I'll write when I find out), but sometimes the EXRs I save from PV are clipped to the luminance of 0,99. I always follow the same procedure:
1) Stop the rendering
2) Denoise
3) Send to PV
4) Save as OpenEXR
5) Post in ArionFX
Corona tone mapping, LUT, bloom/glare and sharpening/blurring are all off.

Clipping happens randomly even in scenes previously rendered without any problems. Recently, a client requested me to re-render a scene in a bigger resolution. It rendered fine a couple of days back in the same version of Corona (2017-06-27), but two of four new images got clipped to 0,99. Thankfully all EXRs saved from VFB are ok, but in general I prefer saving from PV as it gives a nice, single-layer output without any alpha-related issues. So, if anybody could kindly share a tip for fixing this random clipping, I'd greatly appreciate it:)

Note: Clipping occurs also in version 2017-07-11.

Cheers

Title: Re: Clipped EXR output
Post by: dolain on 2017-07-18, 22:59:07

OK I did some more testing and got a confirmation - the very first test scene gave me a clipped output. I created a fresh file, added a cube, sun, sky and a camera and pressed render. After stopping it and denoising I sent it to PV and pressed ctrl to check the values - all were 99,6% although the image was way overexposed.
Interestingly, repeating the same steps in another new file gave correct results (values above 1 as expected), so it's hard to even call this a bug since most of the time it doesn't exist:)

BUT I've noticed another thing - one that happens every time (thankfully). Once we've got our finished image in VFB and check bloom/glare, we lose values above 1 when the image is sent to PV - that's understandable. The bad bit is that after unchecking bloom/glare in VFB and re-sending the image to PV, it remains clipped, which should not be the case imho. Can this be fixed in future releases?

Cheers

Title: Re: Clipped EXR output
Post by: dolain on 2017-07-18, 23:35:45

Just a small update - changing the exposure in VFB after rendering clips the image in PV to 99,6% every time. A bug, clearly. Hope we'll see a fix soon:)

Title: Re: Clipped EXR output
Post by: houska on 2017-07-24, 10:46:52

Hi dolain and thank you for the exact description! We will have a look at this.