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- Rendering Techniques > Using Sun and Sky in mental ray with Maya (Posted By: 3dmonster)
:: Post Date: 2007-09-13 16:21:48 [Post Comment] [Post Articles]
Using Sun and Sky in Mental Ray with Maya
Application Used: Autodesk Maya
Author: Bogdan Amidzic
Using Sun and Sky in mental ray
With Maya 8.5 mental ray's got some new fancy options and modes. One of them is the Sun and Sky system. I'm going to guide you through some of new features.
Create a simple terrain and some object on it. I've created a high-tech tower, but you can make whatever you want -- just add some small details because I'm going to show you how to make them more obvious.
For starters, you'll need to load mental ray. To do that, go to window/settings preferences/plug in manager. Enable Mayatomr.mll
In render globals, choose mental ray. In mental ray globals, you can see the environment tab. Hit Create Physical Sun and Sky.
In the attribute editor, mia_physicalsky1 will appear. There are menu options, I'm going to show you only the few most important ones.
Also there's directional light in the scene. This light controls the direction of the sun and also the time.
If you render, you'll get something like this.
In quality presets, choose previewFinalGather. This will set sampling slightly higher than draft.
On sunDirectionShape, in custom shaders tab, you'll see that light has a light shader, and photon emitter connected.
Mia_physicalsun defines the sun itself. Samples define the number of rays used for shadows. Increase this number if there's noise in shadows.
In the hypershade, you can see all of the shaders used in the Sun and Sky system. There's mia_exposure_simple1 applied as lens shader on camera. This node remaps colors to the way human eye sees. In mental ray all intensities are in linear space. Human brain sees color in a different way. Basically it's a logarithmic function. That's why gamma is 2.2. That's the way we see, same thing for all photographs. So if you apply texture to objects you will get something like this:
It's washed. Why? Because texture has gamma 2.2. The way we see it. So mental ray uses texture with gamma 2.2 in linear calculations of light intensity and then it converts it to gamma 2.2 so we can see it right. So gamma 2.2 is applied twice. That's why the texture is washed. How are we gonna fix it? Simple -- use the gammaCorrect node. Apply gamma 0.454 to image. In that way it gets linear. Then renderer applies gamma 2.2, and it looks good.
In new mental ray, there's also a new shader called mia_material. It's a shader with lots of options, like glossy reflections, built in ambient occlusion, interpolation optimizationsâ?
Apply that material to the tower.
Apply texture with gamma correction.
Also set reflectivity to 0. We are not going to use it in this tutorial.
Also one more important thing about new mental ray. Final Gather has new options -- now it works pretty well with low accuracy settings (same as rays in earlier versions), point density defines how big the Final Gather radius will be. With 50, 0.1 results can be pretty nice and fast.
The thing I wanted to show regarding the mia_material is built-in ambient occlusion. So now final gather is used to get overall ambient lighting and ambient occlusion will darken corners, so details will appear. Ambient occlusion has a few options. Rays define accuracy; raise it if you have noise. Distance defines how far mental ray will try to find occluding geometry.
So without ambient occlusion..
And with ambient occlusion.
Also in mia_physicalsky, there's a haze attribute. Raise it to get foggy diffused lighting.
Red/Blue shift attribute controls the balance between blues and reds. Negative values mean more blue and positive more red.
Comments: (Currently there are 23 comments.)
- [Anonymous] ( 2011-09-12 17:12:29 ) [Post Comments]
|how to create in night mode???????????|
- [Anonymous]anonymous ( 2011-05-27 02:14:35 ) [Post Comments]
|how can we create a night scene ??? help please and thank you for this tutorial|
- [Anonymous] ( 2011-05-09 22:42:50 ) [Post Comments]
- [Anonymous]gandhi420 ( 2010-08-10 05:07:03 ) [Post Comments]
thanku vry vr vry vry much god bless u master
i was dyeing 4 dis light
gamma i was looking 4 that exactly thing
god bless u
- [Anonymous] ( 2010-04-24 02:30:09 ) [Post Comments]
- [Anonymous]DavidP47 ( 2010-04-13 19:34:02 ) [Post Comments]
|This tutorial is great but the best ones are the Maya Tutorials At Cgwhat|
- [Anonymous]Nagendra Gaonkar ( 2009-12-17 23:16:35 ) [Post Comments]
|Very nice tutorial dude, Thank you.|
I have one doubt now, if I want to hide the ground part, how can I do that?
- [Anonymous]ravi shinde ( 2009-09-19 16:50:43 ) [Post Comments]
|very empresive cool ......|
- [Anonymous]umakant7 ( 2008-12-03 15:22:29 ) [Post Comments]
|it¡¯s realy great tutorial.|
the person who want to learn lighting/mental ray , it¡¯s realy very usefull.
thanks for publishing this tutorial.
- suresh ( 2008-06-16 13:50:30 ) [Post Comments]
- [Anonymous]Waran ( 2008-04-21 01:21:03 ) [Post Comments]
- [Anonymous] ( 2008-03-09 10:09:14 ) [Post Comments]
|yeah man , very usefull tuto.|
thankyou very much.
- [Anonymous]buddings ( 2008-02-20 03:41:48 ) [Post Comments]
|how can i use mental ray sun/sky to create night. any help appreciated!|
- [Anonymous]SUBHENDUNAYAK ( 2008-02-10 00:09:44 ) [Post Comments]
|IT IS SO GOOD BUT IN TEUTOREAL YOU DONT GIVE SHADER AND MATEREAL RELASHTIONSHIP. PLES YOU HALPP ME,I NEED SOME LIGHTING TEUTOREAL .PLS SENT THIS ADDRES-SUBHENDUNAYAK18@YAHOO.COM.PLS......|
- [Anonymous]Addepat ( 2008-01-15 21:56:39 ) [Post Comments]
- [Anonymous]rararasputin ( 2007-12-26 00:24:28 ) [Post Comments]
|hey my man ...perfect...;)|
- [Anonymous] ( 2007-11-28 21:18:43 ) [Post Comments]
|Good tutorial... but looks more like a "dude, look what can I do" then a tutorial :)|
- [Anonymous]mayaman ( 2007-11-25 23:17:38 ) [Post Comments]
|hi, How I get evening or night ? depend it on position of direct light ?|
- [Anonymous] ( 2007-11-23 08:05:21 ) [Post Comments]
|How to apply the gamma node:|
1.Under Utilities you'll find the Gamma Correct node.
2.Pipe the texture into the Value of the Gamma Correct node.
3. Set the Gamma to .454.
4. Pipe the Outvalue of the Gamma correct node into the color of your shader.
- [Anonymous]spacefly ( 2007-11-16 12:23:03 ) [Post Comments]
|Great tutorial, but I haven't figured how to connect the gamma correct node to textures. |
If you could please explain.
- [Anonymous]Maya USer ( 2007-10-21 09:13:32 ) [Post Comments]
|I agree with oneurbanman. This is a great tutorial but how do you make the gamma correct connections in the hypershader????|
- [Anonymous]oneurbanman ( 2007-10-12 01:45:01 ) [Post Comments]
|im sorry you say :apply gama to image,but dont explain how to do the conectoins in the conection editor.|
which output form the file and which input for the material?
- [Anonymous] ( 2007-09-25 15:03:11 ) [Post Comments]