ctrl_irradiance


#1

what it does is to let you compose the final result by tweaking directly the color for fg emissions and
irradiance… the fgemissions are controlled with something like the raytype in xsi or the one made by
szabolic… here you get also an HSV color corrector to better manage the effect… it simply catches the fg
rays and return the shader after implemented the c.correction… this happens only for the fg and photon
rays… that is…

  • use the emission tab to get fg into the scene… basically how much that color will
    contribute to the final fg/gi solution… enabling emission will let you overwrite the standard emission for
    the shader… if you have already an emitting material, like a constant or one with incandescence enabled
    you can tweak that ‘emission’ with emission tab params… if not you can specify directly a 2nd color just
    for the fg calculation. the scene example is when you have a sphere dome ‘emitting light’, here you ctrl
    how much light will be in the scene from the sphere, how much is saturated that color and so on… by
    tweaking the saturation you’ll get rid of overbleeded skies while maintaning the right colors visually.

the irradiance otherwise ctrl how much of that fg solution will be showed on your material… and it is in all
the aspect the same as the irradiance controls you’ll find under the maya materials (mentalray tab)…
that for using this one you’ll have also to [color=white]put to black… here the default values act really as the default [/color]
from maya… what does the irradiance function? compute the irradiance, multiply that for the diffuse color
and then add the whole to the final color for the mat… here you have the possibility to use a different
color from the diffuse one… with maya mats the diffuse color is inherithed from the diffuse slot… here you
can specify a different one… if not should be the same as your diffuse… and also you can fine tune your
colors mood under a fg/gi env… that is different than just tweak the diffuse color… so in general…

  • use the irradiance tab to fine ctrl the fg solution on that material, to control overexposures I have
    implemented a really fast and smart tone mapping algorithm[size=2] that without have to make a whole pass, [/size]
    can get rid of overexposed zones while maintain the same ambient and color scheme by exposing the
    virtual sensibility and aperture for that color conditions (the second sphere is just tonemapped).
    the scene example is when you have already made the light and gi setup but you find your obj too
    overexposed or maybe to dark and not so in contrast with the whole scene and you wanna simply
    color correct them as you were in a non gi env.

obviously you can enable both of them for your materials.

the basic setup is:: put to black the irradiance for your maya material, plug it into the input of the
ctrl_irradiance shader, enable irradiance and then tweak your params.

a little addendum is to consider the photon shaders in maya. that are a litte weird… each illum mat has
already a photon part… but this one will work only if the last shader will be that material… that is if you
use just a simply colorpasstrought node… it wont work (maybe use the surfaceshader shader…)…
so I exposed the maya_photonsurface shader and you can simply use this one and plug it into the
photon slot for the mr mat and get full ctrl over your shader net… it is true that the params there should
match the ones of your diffussive mat… but better make a phen to link those then use the maya buildin,
at least for me. do not (re)register in the mr rayrc file… just put in the include folder.

**

ciao
francesca


#2

Where does the .fti file go…sorry for a stupid question.


#3

Obrigado=thank you again Francesca:thumbsup:

annaleah put those files into C:\ProgramFiles\Alias\Maya6.0\icons:)


#4

Thank you.


#5

Wow!

That’s all I can say for now, I must test this out!


#6

You are a super genius. This is exactly what I needed.

THANK YOU.


#7

Thanks for the contribution Francesca !


#8

Grazie, Francesca!

Haven’t had the time for testing, but overexposed regions have been a problem in many renders I did. Great!!!

-Grafix


#9

Hoha! Tested… All works great on maya 6.0.1 :thumbsup:


#10

ouch… there’s a little error in the .mi file… line19 update to this

scalar “m_contrast_e”, #:default 0 softmin -1.0 softmax 1.0

ciao
francesca


#11

It really is a great shader Francesca. What are the ‘power’ and ‘power k’ settings for though?

I’m going to try and add button to the AETemplate called ‘Reset’ that gives you back all the default settings, because there’s a lot of them!


#12

thank you francesca :slight_smile:


#13

Waw!! It’s really useful shader !! it solves tons of problems when your Final Gathering !
Thank you very much for this precious gift.


#14

Thanks Francesca - you’re really out there in a league of your own; a shining star :slight_smile:

Atwooki


#15

erm… It sounds really interesting!!! But I really can’t figure how it’s working:shrug: .

I have tried with a simple sphere/plane lighted with IBL and tried to play with the tonemapping function but it doesn’t seems to change anything whatever I try.
Is it possible for someone to upload a similar test scene? Or just give me some steps? Or is it just me who a bit dumb on this one?..

What I would like to do is to use an existing material and use the tonemapping to avoid the overexposed areas…

Thanks in advance…

Pascal.


#16

What I would like to do is to use an existing material and use the tonemapping to avoid the overexposed areas…
set to black the irradiance for your material… plug it into the color input of ctrl.irrandiance… check the tweak.irradiance… check the use.as.diffuse.color and set it to the same as the diffuse color of your material… tweak.

ciao
francesca


#17

ctrl_irradiance_V1.2

I implemented a new amazing feature from mentalray3.3… we can ctrl FG/GI settings in the hypershade… on a per-shader basis. :slight_smile:


*when in view dependant mode…
the fg overwriting will consider the min and max settings as they were pixel of your screen image…
1 is 1 pixel…

ciao
francesca


#18

you rock francescaluce :love:

thx


#19

Great great great!

I’ve been using view dependant FG a lot lately and it’s really cool.


#20

Thank you francescaluce!