Sky HDRIs

[rhino]

You can adjust those HDRI's simply by using smaller numbers like .003.

[gafl]

Yes I know how to use it, but You Have a lot Of Noise when there is the Sun.
A speciale method is explained to avoid that.
When the sun is low and somewhat hide by the clouds, there is no noise
and it works as any other hdr map...

Have you tried them ?
Gael

[Trapezium]

Gael, I didn't get a chance to read that yet. So have you had any luck with the methods described in the PDF?

--Jon

[gafl]

here is the method from Paul debevec


5. RENDERING AND RESULTS
The captured lighting presented here could be used to ren-
der any outdoor scene providing realistic illumination as well
as a sky backdrop. Due to the extreme contrast between the
sun and sky, the standard global illumination algorithms will
produce a large amount of noise, as they will have di±culty
sampling the sun su±ciently.
Algorithms have been developed for intelligent sampling of
the environment with priority given to high intensity regions
such as in [2]. We utilize a simpler solution, approximating
the sun as a 0.53 degree diameter directional light, while us-
ing traditional sampling techniques for the remainder of the
sky. Pixels in the lighting environment that are above a high
threshold are set to black and represented by a directional
light; this directional light is placed at the weighted cen-
troid of the blackened pixels and set to their total energy.
By manually adjusting the threshold, we select a balance
between accuracy and noise.With this method we rendered a synthetic scene, illumi-
nated by an entire day of captured light, using the Arnold
global illumination system [8]. Several frames are shown in
Figure 7. For these frames, the threshold was set to the peak
cloud intensity in the sequence. These datasets have allowed
us to visualize the full dynamic range of natural illumination
over the course of the day, as seen in Figure 6.


If you understand better than me, explain it to me and I'll give you a glass
of wine, or champagne or cognac or milk ?
Gael

[Trapezium]

If you understand better than me, explain it to me and I'll give you a glass
of wine, or champagne or cognac or milk ?
Gael

ok, I'll try but no promises yet

BTW, would you mind sending me two of the images? Maybe one with sun and one without. I can't download that large zip file here at work and all I have with me are the two I corrected in HDRI Shop.

Thanks,
--Jon

[Trapezium]

Ok, I'm home now so maybe I can help. Just going through the information now.

Basically what I've decided to do is use the Splutterfish loader set to shperical environment. It's just as effective as the mirrored ball type, both have a black area which can be positioned out of view.

--Jon

[gafl]

Hi !
I'll give you tow ones in a minute...I thought someone had already given one to you.Sorry, I didn't try.
Where can i send them to you ???
One image=1220 ko


Yes this holly black area...
Normally it's in real pixel mode.
Good luck !
Gael

[Trapezium]

No problem on the images now I got them from home. Thanks though.

As far as I can tell, it's not really anything we can do to adjust these. It's in the code if I'm reading correctly. When he writes that we did this or that I think that it means they wrote some custom code that works with the Arnold renderer.

--Jon

[RErender]

Doesn't it work to set the white point in the splutterfish loader to ignore the sun area? The custom code is to place the direct light to match the sun position as I understand it. There is a skydome script that places lights per the colors of a bitmap, I think it might be possible to modify it to find the sun area in a hdri.

[Trapezium]

Yeah, the Splutterfish loader is the only solution I've found.

I guess I was under the assumption that they wrote something similar to the SFLoader for Arnold but it probably handles this inherently.

--Jon

[Trapezium]

Just found a Lightgen converter script on www.scriptspot.com for use with text output from HDRI Shop.

--Jon

[gafl]

Hi jon !

Do you understand better what I said ?
I don't really understand the fact that the hdr sun should be "hidden" and replaced by a direct light...
Why did they care to add it in the hdr map so ?
They know better their work than me sure !

If I have some time I will adjust the sun area in a hdr tool to reduce its intensity directly and save it like that.

I wait for your tests.
Bye
Gael

[vlado]

Hopefully in one of the next builds, the Dome light will support adaptively sampled environment maps, so you will be able to render even very difficult HDRI's with little noise...

Best regards,
Vlado

[gafl]

Hi vlado !

How much kind you are, you are incredible !
If I were a girl , I would kiss you and all the team !!!!!!!!!!!!!

I hope you will find a method with this hdr skies and will explain it to us.
It may be very interesting to work with.

Thanks a lot
We will wait ...
Gael