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Re: hdri vs whitout

Posted: Fri Feb 05, 2010 5:38 pm
by Sam
A small warning about blurred HDRI
If you blur too much the HDR the reflections gets blurry wich is cool because its faster than blurry reflections (using roughness)
But not the other reflections from the real objects like the ground in your example, they stay sharp.. wich is kinda weird in some cases ;)

Re: hdri vs whitout

Posted: Fri Feb 05, 2010 5:44 pm
by samartin
Yes the reflections do get blurred, it's not the best way to do things, maybe I should have used more diffuse type materials to demonstrate. I.e. if you had an architecture piece like the 1st example, the diffuse (no reflective) areas would be dithered like mad.

However having a simple controller to alter the HDR could be great in lowering baking times given the right environment.

I forgot to say that both examples baked for the same amount of time, about 20s a piece (using Fprime).

[edit]

Just done a quick diffuse test and cropped a certain part, they were both rendered for the same length of time and you can see the benefit from just a simple control.

Re: hdri vs whitout

Posted: Fri Feb 05, 2010 5:56 pm
by Sam
For settings inside Octane here's what I already used in production that could be very cool to see as nodes

- Changing the type of projection of an image, from panorama to spherical lightprobe to cross etc...
- Shoulder-pad (bringing down a little bit the very bright area of the HDRI)
- Color correction nodes should work in 32 bit for HDRI also
- 32bit Gaussian blur node for all images
- 32bit Lens blur node for all images
- Exposure correction for all images
- Converter from EXR <-> HDR (because there's not a lot of tool, beside photoshop for it)
- Bilateral filter (smooth an image but keeps sharp edges, meaning less artifacts)
- Diffuse SH (see HDRLABS > Picturenaut > Filter plugins for more info) its a blur-like-diffuse-like that keep seamless

Example, the HDRI is seamless from left to right even blurred, with photoshop blur you break the seamless attribute
ImageImage
Pictures from Picturenaut page

You could also contact Christian Bloch again, he know a lot more than me about post-processing HDRIs :mrgreen:
I think we need a topic just about HDRI, because there's so many things to say about it ;)

Re: hdri vs whitout

Posted: Sat Feb 06, 2010 4:24 pm
by Tugpsx
How about an option to add a backdrop, this way you can get the lighting control of the HDRI but maintain a solid or gradient backdrop in a product placement environment.

Yes I know i can place the object in a white room and try to get a similar effect but then the room would be affected by the environmental light too.

Re: hdri vs whitout

Posted: Sat Feb 06, 2010 4:27 pm
by radiance
Hi guys,

These are all pseudo solutions that will automatically be solved with upcoming MLT support, which is nearly finished.

Radiance

Re: hdri vs whitout

Posted: Sat Feb 06, 2010 4:47 pm
by Tugpsx
ooh! thanks for update.

Re: hdri vs whitout

Posted: Sun Feb 07, 2010 4:29 pm
by Stereomike
MLT was to get rid of hot pixels right? Would it also bring down rendertime like blurring the lightspending-HDRI does?

@Sam: true, a blurred HDRI would cause losing reflection details. A way to circumvent this, would be allowing different images for reflection an lighting or kinda switch like "blur affects -Lighting and reflection- or only -lighting-".

Re: hdri vs whitout

Posted: Sun Feb 07, 2010 4:34 pm
by Sam
Stereomike

Already asked for Smart IBL support here http://www.refractivesoftware.com/forum ... sibl#p2970
What you are describing is exactly how sIBL work :lol:

Re: hdri vs whitout

Posted: Sun Feb 07, 2010 7:11 pm
by Stereomike
Cool, I dl'ed several versions but never used or even tried it, thanks for the brief explanation in that thread. I 'd like to have it in Octane as well :)

Re: hdri vs whitout

Posted: Sun Feb 07, 2010 7:13 pm
by Sam
Beside sIBL it would be good to license some of the HDR they got in their gallery... some are very good
I hope you have seen this thread there's plenty HDRI for you to try