cgShaders: for mental ray and 3dsmax

Download: not available yet

contact sam@cgcharacter.com for download

WE have designed a number of shaders to help reach the aim of lighting from the environment rather than with synthetic lights. This has resutled in a nubmer of experiments along the way.

Please feel free to download our software but if you use it on a commerical project we urge you to pay the shareware fee of $US 49

Spherical Harmonics:

Spherical Harmonics are a group of mathematical functions that encode information about around a 3d polar coordinate system to encode complex information into very small parameter set. The higher the order of harmonics that you use the more detail you can encode and the larger the number of parameters.

Initially the spherical harmonics have been used to encode simple diffuse lighting with just the second order of psherical harmonics. Once higher order spherical harmonics are used we will be able to use them for encding the specular high lights.

Spherical Harmonics Stack:

A way of combining a number cgShader together into one super spherical harmonic

Please find three tutorials about spherical harmonics attached:

Spherical Harmonics Tutorials:

Spherical Harmonics 1: A synthetic source of environmental lighting

Spherical Harmonics 2: Converting a HDR lightprobe to diffisue spherical Harmonics

Ambient Occlusion Normal Light Map

Ambient Occlustion has been in use for a few years now as a way of adding dirt to yoru objects or shadows in the corners of objects, now we can use it with an environment to use it as a form of envinoment based lighting.

Ambient Ccclusion Tutorial:

a GI fake, can be used for image based lighting.

Normal Light Map

Usign enivroment based lighting typically means that the a map is used as a lightsource and a global illumination solution is used to trace light back to the light source map. Using a normal light map, we make the shader self illunated and use a diffused version of the lighting to represent the diffuse pass for the lighting. This is a very quick pass. It makes use of the normal to look up preconvulted version a longtitude lattitude version of the environmental light.
This shader also allows for the environment map to be adjusted pitch and yaw of the Material to be adjusted.
THis shader is now superseeded by the ability of a Spherical Harmonics map to convert a map to a diffuse light source.

Normal Light Map Tutorial:

Using Normal light map for diffuse pass

Exposure:

The exposure map was made out of the nesscity to be able to adjust the output of spherical harmonic lighting.

Works the same as any image adjustment function that you may find in a image eidting or compositing package.
The input values are adjusted to give new output values. Adjsutments can be made on red green or blue
As all calculation are doen in floating space you cna get values greater than one and less than zero so you can produce some pretty weird and unwanted results if you dont knwo what you are doing.

Legacy Shaders:

Reflect:

A way of adding a custom environment to your reflections. This shader is not supported

Add:

A legacy shader for simply adding the result of a number of maps. simply adds pixel values

Tutorials

Coming soon
Using mapped gradient ramp to create specularity map, glossiness map and diffuse from HDR.

See movie now download