Page 1 of 1

Blurring scene, but not HDRI in background

Posted: Thu Sep 07, 2023 5:54 pm
by xientce
Hi all,

Have a problem for you all!

I've got a scene, a gold metallic object that I want to have heavy DOF on. I also want the metal to reflect the HDRI background.
But, using DOF in C4D Octane camera means my HDRi is also being blurred.

Is there anyway in Octane to have my foreground be blurred, but my hdri background be clean and sharp?

Any help is always appreciated!

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 3:10 pm
by frankmci
If I understand you correctly, you just need to set your focal depth pretty high, so that it's well past your near, blurred objects. The environment should stay crisp.

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 3:37 pm
by SSmolak
Maybe someone knows how to avoid blur in reflections ?

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 4:43 pm
by frankmci
SSmolak wrote:Maybe someone knows how to avoid blur in reflections ?
I was fooling with this a bit and it looks like Octane is treating perfectly flat reflective surfaces the way you would expect, optically, but not surfaces that have any phong smoothing applied to them at all, even an otherwise perfectly flat cube with a small corner radius. Right side, cube no radius, left side, cube with radius. The right side is optically correct. Remove radius on left cube, its reflection becomes as clear as the right cube. Kernel choice and sampling levels don't seem to make any difference.

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 5:45 pm
by SSmolak
frankmci wrote:The right side is optically correct. Remove radius on left cube, its reflection becomes as clear as the right cube. Kernel choice and sampling levels don't seem to make any difference.
Thanks but I mean situation while focusing on cube. How to avoid background blurring on reflective surfaces that are on focus like this :
refl_DOF_blur.png

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 7:53 pm
by frankmci
SSmolak wrote:Thanks but I mean situation while focusing on cube. How to avoid background blurring on reflective surfaces that are on focus like this :
Ah, I was thinking you wanted it the other way around. In your situation, Octane is behaving as it should, optically. To get the reflection of distant, unfocused objects to be focused in a reflection, you're going to have to cheat. It would look funny, too, in my opinion, even if people don't consciously know what's wrong. But if you need it, you need it. I think you'll have to do two different DOF passes and comp them, one for your geometry, another for your reflections.

Re: Blurring scene, but not HDRI in background

Posted: Fri Sep 08, 2023 8:58 pm
by SSmolak
frankmci wrote: Ah, I was thinking you wanted it the other way around. In your situation, Octane is behaving as it should, optically.
Yes I know but in architectural visualizations clients wants little DoF but clear reflections in windows :) Exclude from DoF in Octane Object tag would be great for that.