Class02 - HDRI environments - sIBL

This class will break into three examples of lighting with HDR images, or Image Based Lighting (IBL).

-        Physical Sun and Sky

-        HDR panoramic image with sIBL software

-        Simple env setup for HDR panoramic with mib_lookup_sphereical

Begin with a physical sun sky example to show how Maya can create an HDR environment for you, and use it as a background.  Vue, Bryce, and other 3D packages can be used to make HDR environments for lighting, but in the end photo reference for this stuff is the best, more detail.

Linear Color Workflow with textures and Physical Sky

Summary: 1)how to use and fix gamma of Physical sky 2)how to verify that our textures are color managed

CONCLUDE: 1)always watch for lens shader on the camera when using scripts and tools, be aware of color profile of all incoming textures and colors. 2)mia_x shaders are better because of energy conservation, and no specular component, all spec is refl.

HDR Panoramic images, show the collection of sIBL’s at HDR labs.

http://www.hdrlabs.com/sibl/archive.html

IBL or Image Based Lighting

Summary: 1)using HDR images from the web 2)combine direct and indirect lighting by mixing dir lights and FG from the blurred HDR image 3)get rid of noise from HDR images

http://www.youtube.com/watch?v=umFAl3-fGkA

CONCLUDE: 1)always verify light intensity, and mapping of HDR you get from other sources 2)you can always mix and match the HDR image lights with direct lighting 3)important to split the light into diffuse and specular components, for speed increase and get rid of noise in FG.

sIBL demo with Pegasus statue in the desert HDR image.

Summary: 1)show the sIBL gui software 2)make sure to correctly use Maya Color Management with 3rd party software like sIBL 3)describe sIBL creator, and how these tools are a time saver.

DEMO: show the sIBL interface, explain how it splits light into diffuse and specular components, and some direct sun lights for shadows.  Open Maya, 1st desert sIBL, then Pegasus head, render bad colorspace, fix all colorspace, graph shader network and explain, open results in Nuke to verify, show buddha animation, describe how VFX industry often uses this idea of “split the light“.

CONCLUDE: 1)sIBL is a short cut tool that you can use, but not necessary 2)it is a great way to experiment with many free quality IBL environments quickly 3)important to understand Color Management in Maya when introducing new tools.

Create a simple version of the same environment network we had when using the 3rd party sIBL software.  This network we create does exactly the same lighting, but may not be as easy to tumble around and interact with, but it allows us to do everything in Maya with no additional plug-ins.

mip_rayswitch,

mib_lookup_spherical,

mip_matteshadow - this shader gets applied to all “stand in” objects

mia_physicalsun - this is an optional modify to your sun directional light

You have three textures coming in from an sIBL set (1) RT 3k hdr, (2) FG  small blur hdr, and (3) BG 8k jpeg.  Each of these image files goes into a default matching mib_lookup_sphereical node.  This node does the rotation positioning, with some acute disadvantages, mainly that you cannot see it in the Maya window.

(1) Refl 3k hdr -> into rayswitch env, refl

(2) FG blur hdr -> into only final gather

(3) BG 8k jpeg -> into rayswitch trans, refract, and eye

Then the rayswitch goes into the Mental Ray tab of the camera you render from.  For the ground plane you apply a lambert that has a mip_matteshadow in the shading engine.  This matteshadow gets output of the rayswitch into its main color, this makes the ground have same color as camera will give to it.

The Mental Ray production shaders are hidden by default.  mip_* mib_* mia_*

Simply go to your script editor, type in:

optionVar -iv "MIP_SHD_EXPOSE" 1

Also check out info on the finest in Mental Ray websites from Zap

http://mentalraytips.blogspot.com.br/2007/10/production-shaders-hidden-treasures-of.html
also
type in createNode mip_whatever to create them individually every scene, this sucks, but works
createNode mip_matteshadow;

http://www.tokeru.com/t/bin/view/Maya/MayaMentalRay#Enabling_the_mip_shaders_in_2009

To find more info you can always search "Mental Ray production shaders" as well as read the 2013 Mental Ray production manual online.

http://docs.autodesk.com/MENTALRAY/2013/ENU/mental-ray-help/