Vray reflection mapping

thomthom

Did a little test scene. Used an HDRI as I wanted to get a colour tint to the lighting. Too bad the Sun shadows are gone. (If I remember correctly, I can get them if I turn on default light and decrease the GI light while also adjusting the camera exposure.)

ibon

Very beautiful scene thomthom. I have tried to make my own with an HDRI map but after more than 10 trial errors can't get the desired position for my sun. Is any easyer method to quickly position your hdri?

thomthom

Hide all geometry, or do material override so it renders quickly and then do a few trial and errors of the HDRI horizontal position. Or you could do what Richard do; quite nice setup: http://www.sketchucation.com/forums/scf/viewtopic.php?f=15&t=18001&p=145253

Note that you won't have much luck if you try to adjust the vertical position of the SUN source from and HDRI. That will just mess things up.

nomeradona

@unknownuser said:

lol. Nevertheless I'd like to see, say, Damien Alomar elaborate on this issue. He usually does a good job explaining things.
yeap, whenever damien reply assurely my eyes are there...

nomeradona

@unknownuser said:

Whoa! Err ... dankie? Dankiewel? Whatever - thanks!
Oh thank God FA is here to give some explanation about this.
hey stinkie are you saying FA is a donkey? lol.

nomeradona

thats a cool linking render Thom

thomthom

What I'd like to know is how to create a render with a tinted sun but with sun shadows as in the picture posted by the original poster. Anyone got some tips?

kwistenbiebel

@thomthom said:

What I'd like to know is how to create a render with a tinted sun but with sun shadows as in the picture posted by the original poster. Anyone got some tips?

That is where VrayforSU fails, as I stated before. Having a 'sun object' (an infinite light with a target) would be the solution, but considered impossible by Asgvis (why?). Cinema 4D's and Max's Vray versions both have the option to create a Vraysun.
In that way you can control the HDR and sky settings in the environment tabs, while controlling the direct light/shadows by the sun object.

In VfSU, all settings, including sun, need to be done by setting up the environment slots (GI,background, reflection, etc..)

The only way I found to more or less fake a HDR/Sun/sky combo was the following:
GI : use sky with 0.5 sun intensity
Background: a bitmap with 30000 multiplier
(optional : Reflection: a bitmap with a varying multiplier (10000 to...) to achieve the result you're after.)

These are values that worked for me in VfSU 1.0 . It might be a different case for later versions.
It's still difficult to get it right though....

thomthom

I also don't understand why we can't have a Sun object. We have Omni and rectangular lights...
So the problem stems from that we can control the VRay Sun and the VRay Sky separately?

Maybe this is something we can ask for as a topic for the webseminars...

@kwistenbiebel said:

The only way I found to more or less fake a HDR/Sun/sky combo was the following:
GI : use sky with 0.5 sun intensity
Background: a bitmap with 30000 multiplier
(optional : Reflection: a bitmap with a varying multiplier (10000 to...) to achieve the result your after.)

Yea, this is what I've tried before. But I feel it's a hit and miss.

I wonder; would an alternative method be to place a rectangular light in the Sun's position? How would you balance the GI HDRI light and the rectangular light?

kwistenbiebel

I tried using a rectangular light but the light is 'flat'.

The sun really needs to be an 'infinite' light to behave realistically.

solo

Guys, this is probably slightly off topic however I need to know about Vue to vray integration of HDR images, I have created a simple .hdr sky and wanted to know how it works with Vray (I suck at Vray hdri usage) so if a knowledgable user could try the attched file and let me know i would appreciate it.

Vue created hdr image

thomthom

Hmm... That's and odd HDRI sky. Why isn't the horizon flat?
Do you know what kind of format this HDR are supposed to be?

I tried with spherical mapping. But it just came out odd. The first two have Verical Repeat of 3. The last two 1.

(Why doesn't the multiple upload work?)

solo

Great, I did something that I would normally not do so the result is as expected, I have another one that was done the standard way attached, the horizon should be fine now.

Could you post a quick walkthrough as to your setup? I need to know how to create hdr image renders in Vray sometime.

solotest1.zip

thomthom

That still doesn't look like an environment image. It needs to be covering 360 degrees. Spherical, cube cross format for instance.

solo

Okay, then if I render the sky as a spherical 360 panarama and save as hdr it may work, lemme give that a go

thomthom

My setup: With default physical camera settings:

Load the HDR image into the GI and Background maps
Set the mapping to Environment
Set Multiplier to 50 (Depending on the HDR, usually somewhere between 20-50. GI and Background often have slight different values.)
Adjust the Horizontal Rotation to orient the HDR sky as I want.