Environment Configuration, a few questions...

When I try a IBL, I wanna mean: I want to illuminate an exterior or interior scene with a HDRi file...
a).-Light beams project shadows better or worse defined or only create global illumination?
b).-If light beams are created, can I control their direction ?
c).-Are they controlled with the plug-in parameter "angle" within the Environment Configuration settings?

I'm making a few fast tryings but if someone can tell us a few resumed advices...

Thank you.

To make the illumination look good then you need a good HDRI map, and i dont know what you mean with light beams.... if you mean volumetric light, they arnt calculated in fryrender, but there is a channel wich you can use inside photoshop later, but that wont affact the illumination at all...

With light beams I want to say if with a HDRi map you can iluminate enoguh till you can create shadows with their respectives edges more or less defined over the surfaces the shadows are projected.

Thank you.

Well fryrender did enhance the IBL mode, so it should be able to do that.... i dont know what the hdri map will need for that to work proberly, maybe someone with more experince could shine some light on it?

I think we have auto-answered the question and I have been making some experiments with a simple scene:

1st).-If you have the adequated HDRi map, you could generate the shadows with sharp edges or with soft edges. It depends how soft is the withe zone on the HDRi map. If the white zone of the HDRi map has soft edges your shadows will be with soft edges and the same for sharp edges for the white zone and the shadows.

2nd).-And respect to the "angle" parameter: if you rotate 90 degrees all will change 90 degrees. The light, the shadows...

3rd).-And the best of all is that the efficiency parameter is increased by 3 times...More or less 3 times less in render time.

If something about what I have said is wrong, please correct me.

Regards.

It would be good to see some example renderings to show the differences in settings when using IBL.
This is what the official Fryrender board says about IBL (credits for the images go to the Fry beta testers: Erwan,Realistic design and Mane162, text by Chema, developer of fryrender):


fryrender vBeta1.9 implements a highly optimized system for environmental Image Based Lighting (IBL).

[i]As you know, HDRI images differ from regular images because HDRIs capture the original power of the colors in them.
For example, a HDRI image of a real sky stores the 'true' power and color of the sky and Sun as captured by the camera.
Same thing applies to a HDRI of a room with a window, or with lamps. So, theory says that if you have a spherical
HDRI of a certain scene, you have an accurate description of the illumination of that scene, both in terms of color and power.

It is possible to assign a HDRI image to the ENV slot in fryrender. This maps the HDRI on a huge (infinite) sphere
around the scene, and uses that HDRI as a big emitter. This technique used to cause a LOT of noise.
The reason for that noise is that HDRI maps are usually quite heterogeneous. Most of them are mostly dark,
and there are some bright spots here and there (the Sun ball, windows, lamps, ...). The more heterogenous the map is,
the uglier the noise. So, in practice, it's not been possible to use HDRI lighting in fry until now unless the
HDRI map was blurred or rather homogeneous.

The new IBL system in fryrender 1.9 is pretty smart. It analyzes the HDRI provided, and tells the core
where the bright spots are. If you want to put it this way, the original HDRI map is fragmented in bright and dark parts,
and a spherical dome of emitters is generated.

For example: imagine a black HDRI map with a white pixel in the middle. fryrender vBeta1.9 will analyze
that map and generate a black skydome with a white emitter with the shape and position of that white pixel,
producing the sharp shadows and strong lighting of that small pixel-emitter immediately. Without the new IBL module,
that white pixel would only be evaluated by chance and the image would take 'forever' to clean up.

Let's take a look at some examples of the new IBL system in action. All these renders took 2 minutes to compute.
On the left, images with IBL enabled. On the right, images with IBL disabled.



As you can see, the HDRI maps used have windows (or the Sun ball), being those extraordinarily bright spots,
while the rest of the maps are fairly dark. Note how the IBL-OFF examples are very noisy,
and how the IBL-ON ones are quite clean despite the short render time. But more than that,
note how in the case of the Sky/Sun HDRI map, the IBL-OFF method fails to capture the Sun light
in a reasonable time, while the IBL mode runs almost as fast as the built-in Physical Sky.

Some quick conclusions follow:

1- Don't fear HDRI lighting anymore. Now it is efficient, and -- IT -- LOOKS -- GREAT --

2- Note that IBL is an incredibly great solution for product shots and exterior renders.
For product shots, IBL is enough to be the whole light setup alone. Just pick a good HDRI,
put your product on a proper floor, and voilá.

3- For exterior shots you may want to use the built-in Physical Sky for clear day shots.
But IBL provides a NEW and incredibly good looking alternative for CLOUDY days and other variants of sky
that can't be achieved with the Physical Sky system.

4- IBL produces the -EXACT SAME- render that you would get with IBL disabled. It doesn't fake anything.
It's just a smart core optimization, so there are no tricks involved.

Some of the greatest product shots that you've seen in the forum lately have been produced with IBL.
Some of them by Erwan you may remember. The row with the fruit bowl contains tests by Realistic Design.







In all those images the ONLY light source was a HDRI map. BTW, you can find some good (and classic)
maps in Paul Devebec's page (http://www.debevec.org/probes).

As for IBL used in exterior shots, this example, based on a scene kindly provided by mane162, will be worth a thousand words.
The render times for these shots was, again, 2 minutes each:



There's no Physical Sky in these shots. Only the HDRI maps that you can find here (http://gl.ict.usc.edu/skyprobes/).
Most of them are great. Particularly the cloudy ones IMHO, and not only the light is great (and real!), but also
depending on the cloudiness, the hardness of the shadows varies, and obviously,
the clouds are visible in the background too.

Some final remarks:

IBL only applies to the ENV slot, and it's enabled by default in vBeta1.9. The only situation in which it is recommended
to disable IBL and revert to the old 'raw environment' mode is for interiors. Interior scenes do not benefit from IBL -at all-
(in fact, there is a serious performance hit if IBL is enabled for an interior shot).

And the most relevant remark of all:

As you can see, the extra quality contributed by all the nuances and subtle hues in a good HDRI map is priceless.

The renders in that pdf is so nice
Altough i do have a feeling that the HDRI maps i use have to soft light spots, cause i never get the hard shadows

Wow! That's fantastic!

Thank you very much administrator...It's evident that an image worths more than 1000 words...

The renders of mane162 are very explicit.

a).-And the most amazing are the impressive result of the HDRis with clouds...A few years ago this was impossible to reach: such a level of illumination and...With clouds!! It's like a dream!

b).-The HDRis collection are really useful (and free). I can't wait to repeat my simple experiments and watch the results like, for instance: edge of the shadows, strength of the filling inside the shadows, and the combination of how results the sky and the ilumination and the shadows how are projected over the surface of my simple scene.

c).-And my personal discover of the http://www.debevec.org/ and the institute where he works...I have realised that he and his team are the precursors of all what years later we can use, enjoy, and play in our 3d render engine programs like Fryrender and Maxwell. And some websites were this team appears I've seen impressive .pdf documents where a lot of complex ecuations in are implemented. All is really well explained so implement this in a high language programming shouldn't be difficult. This is a bit off topic.

d).-Yesterday was late and I could read that with HDRi shop you can modify a Hdri map...Is it true? My lack of work with HDRi maps force me to make this kind of questions as, for example: With newer versions of Photoshop or CorelPhotoPaint can you modifiy too the HDRi maps? I ask these because in this way I would make the white zones of an existent HDRi map with more sharp edges in order to reach more (or less) sharp zones.

Thank you very much for all the information...Indeed really useful.

Regards.

A little update on IBL: the official forum states that IBL is currently broken in version 'ONE'.
That's probably why you can't get those hard shadows going (@Stromberg)

In beta 1.9 it should work fine though.

Let's hope this gets solved in the next update version as IBL is a powerful option.

I didn't know that.

I'm with the RC version.

i didn't know that alsko... What about RC version?

RC mean Release Candidat

it's the last version before the definitive version.

in fact it's almost a definitive version.

I think IBL doesn't work in the RC version neither...

Da Moderator wrote:I think IBL doesn't work in the RC version neither...

that's what i ment