Table Of Contents

Introduction

This is our basic environment shader, which takes a texture map as an input and projects it based on the projection mode.






General

Texture

Texture Mode

This specifies how the textures are to be chosen:

Map

This is the texture map that is to be projected on to the environment.

sRGB / Gamma / Exposure / Hue / Saturation

Common image adjustments.
Most non HDR textures require gamma correction during sampling. If your texture is SRGB compliant then you need to check the SRGB option.


These come from the Clip 'Adjust' properties in Softimage.


Projection Mode

This specifies the projection mode for the texture, of which can be one of the following:

SphericalCylindricalCubic StripCubic Cross SidewaysCubic Cross


Use Image Sequence

Allows you to use an animated image sequence for your environment.

Adjust

Ray Type Intensity Multipliers (Background/Refraction, Reflections, GI)

This allows you to adjust the intensity of the environment, depending on the type of ray that 'reached' it. 'Background' refers to primary 'eye' rays, meaning what you see. 'Reflection' refers to when you see the environment map through a reflection and GI means when you see it through GI rays. For example, HDR environment maps with very bright light hot-spots might cause undesirable noisy artifacts during GI tracing, so in this case you would bring down the intensity for GI only.



Background Intensity: 1.05.00.2



Reflection Intensity: 1.05.00.2



GI Intensity: 1.05.00.2



Alpha Channel Replace Enable

This allows you to over-ride the texture alpha values, which may be necessary if they are either non-existent or not correct. Typically, for environment textures, the alpha value should always be 0.0, if you plan on compositing environment layers.

Alpha Channel Replace Alpha

This is the alpha value that will be used instead of the texture alpha values.



Alpha Channel Replace: 1.00.50.0



GI Affects Matte Shadow Catchers

Normally you do not want to add environment image GI to Matte Shadow Catcher lighting as it will result in 'double lighting', since Matte Shadow background images will already contain indirect light from the environment. However, this option allows you to enable GI contribution from the environment map for Matte Shadow materials; useful if you are using a ray switch and the GI image is not representative of the real environment.

Transform

This allows you to scale, rotate and offset the projected environment image. 

Back-Plate

Enabled

Map

This is the texture map that is to be projected on to the environment.

sRGB / Gamma / Exposure / Hue / Saturation

Common image adjustments. 
Most non HDR textures require gamma correction during sampling. If your texture is SRGB compliant then you need to check the SRGB option.


These come from the Clip 'Adjust' properties in Softimage.



Back-plate Aspect Ratio

This specifies what aspect ratio to use for the back-plate:

Apply Camera Exposure Compensation

When enabled, this disables the Photographic Exposure nodes effect on your camera map.

Ray Switch


This tab allows you to set a texture and projection mode for each ray type. 

Texture Mode must be set to "Ray Switch" in the General section of this shader for these options to become active.





Texture Background/Refraction, Texture Reflections, Texture GI

Map

This is the texture map that will be projected on to the environment for the background, reflection or GI rays.



Background: Sunny Forest

Reflection: Sunny Forest

GI: Sunny Forest

Background: Building Interior

Reflection: Sunny Forest

GI Texture: Sunny Forest

Background: Sunny Forest

Reflection: Underpass Interior

GI: Sunny Forest

Background: Sunny Forest

Reflection: Sunny Forest

GI: Overcast Forest

Background : Building Interior

Reflection: Underpass Interior

GI: Overcast Forest


sRGB / Gamma / Exposure / Hue / Saturation

Common image adjustments. 
Most non HDR textures require gamma correction during sampling. If your texture is SRGB compliant then you need to check the SRGB option.


These come from the Clip 'Adjust' properties in Softimage.



Projection Mode

This specifies the projection mode for the texture, of which can be one of the following: 

For visual examples, see here.


HDRI's used on this page from : www.hdrihaven.com