Setting up HDRI based lighting in Mental Ray

Hi all,
 In this tutorial we are going to look at how we can use  Final gather & HDR maps to create image based lighting scene.

Step1 :

This is the scene that i am going to work with, It's simple setup teapots with some architectural maps.
Ok lets' start first we need to create sphere to work as our environment , go top view  , go to primitive section create a sphere. make sure that it'l cover our scene fully.

Step 2:
Ok , lets apply texture to our sphere. to do that go to material editor ( press m) , select available slot and change it diffuse color and ambient color to black.

Step 3 :

Click on global illumination field, put the check mark and put a bitmap into self illumination field. Apply a HDR map as your bitmap , when importing the HDR map, put the check box in 32 color data field as shown below.

Step 4:

And assign that texture to our sphere.

Step 5:

To add more details to our scene, goto render settings ( press F10), and under Indirect Illumination enable Final gather. ( make sure that you have change your render as the mental ray) . make a test render ( press F9 ) , you can see much more realistic scene.

Step 6:

but we have lot of lights , to override this effect add Standard omni light in scene. make it intensity to lower value ( 0.2 ) .

Step 7 :
 To make more realistic . goto our final gather settings and we need to adjust some parameters to yield a high quality scene.

Step 8:

After some tweaks i get a following render output. Also further we can add some exposure control to our scene.

Step 9 :

To add exposure control goto rendering menu----> exposure control. choose mr Photographic Exposure control

Step 10 :

make some tweaks to parameters as shown in below.

here some example by using several HDR Images.