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Peter Guthrie HDRI

PostPosted: Sun Sep 07, 2014 11:58 am
by thefishnut
I am having trouble adjusting a HDRI that I have purchased from Peter Guthrie. My hope was that it would work out of the box. But I find it is instantly so bright that the screen is blanketed white. I have played around with the HDRI texture power and the environment power, but cant find a happy balance. Is there a recommended base setting when using Peter Guthries HDRI's? I am using a texture environment with the HDRI in the texture node as a RGB image.
Many Thanks.

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 3:57 am
by FooZe
Using a texture environment with the HDRI loaded in as a RGB Image is the normal way.
Are you using the standalone? What do the specs say for the image eg: 6250x3125 pixels, 96 bpp RGB HDR, 305175 KB.
Is is a .hdr file?
Have you played with the textures gamma in octane? (default is 2.2)

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 5:12 am
by Seekerfinder
Also, check your camera exposure & ISO settings. Just perhaps you messed with them in the scene before trying this HDRI.

Best,
Seeker

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 6:27 am
by mbetke
I had the same problems with them. Had to use Gamma 1.0 in the environment slot plus lowering Iso low to 5 sometimes.
I experienced it with other HDR images too and using the 3dsmax plugin there seems no way to set the image up properly while loading (the little white and black point bix which appears if you click it).

I ended up using the CG-Source skies (http://www.cg-source.com/products_hdris ... at=hdrisky).
They work very well out of the box and you can download low-res versions before buying.

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 12:20 pm
by sdwhitton
Peter Guthrie's HDRIs are very bright I find

What I do is open then in photoshop, and add an exposure layer over the top, bring the exposure down a touch

I also resize them to I dunno, 4000 pixels wide

then save this out as a new version

I think he mentions this in his 'faqs'

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 12:22 pm
by sdwhitton
also, once you've made your own re-exposed hdr, try then playing with the gamma in Octane, as this affects the strength / definition of the shadows quite a lot

cheers!

Re: Peter Guthrie HDRI

PostPosted: Mon Sep 08, 2014 1:32 pm
by enigmasi
don't change iso, keep iso 100, gamma 1 to see result better
peter guthrie hdri's very bright, try to keep image's gamma under 1, and very low power

Re: Peter Guthrie HDRI

PostPosted: Tue Sep 09, 2014 6:48 am
by mbetke
If I do this the shadows are nearly gone.

Re: Peter Guthrie HDRI

PostPosted: Thu Sep 11, 2014 11:08 am
by thefishnut
Thanks guys.

enigmasi wrote:don't change iso, keep iso 100, gamma 1 to see result better
peter guthrie hdri's very bright, try to keep image's gamma under 1, and very low power


Why do you say that enigmasi? Changing the gamma to 1 and the iso to about 5 does seem to work. Unless I am missing something. Will changing the iso effect other things I haven't though of?

Re: Peter Guthrie HDRI

PostPosted: Thu Sep 11, 2014 12:06 pm
by enigmasi
I meant keep default settings for CameraImager. Use low gamma for hdri, like under 1 even, and very low power 0.0... because his hdri's are very bright