asBlackbody¶
A blackbody radiator material [CGF:CGF1986] shader, with an optional glossy specular term on top, which also outputs the black body radiator color besides the output closure.
Parameters¶
Incandescence Parameters¶
- Incandescence Type
The type of color for the emitance distribution function, it can be
- Constant
- Blackbody
When in Blackbody mode it uses physically based values, that might have extremely high intensities as the temperature increases.
- Color
- The color to use when in Constant mode, ignored in Blackbody mode.
- Incandescence Amount
- The overall intensity of the incandescence, it can be over 1.0.
- Temperature Scale
- A scaling factor for the temperature value used to compute the black body radiation. Unlike incandescence amount, this actually affects the output color, with lower values generating warmer colors and lower energy levels, and higher values generating cooler values with higher energy levels.
- Temperature
- The temperature to which the perfect black body is heated to emit electro-magnetic radiation.
- Normalize Area
- When objects are deformed, their surface area might change. Without this option, the intensities would stay the same regardless of the deformation of the object to which the shader is attached. It this option enabled, the intensities will change taking into account the object surface area, in order to keep the amount of emitted energy constant.
- Tonemap Color
- As temperature increases, the black body radiator emits color in bluer wavelenghts, but the amount of energy emitted is extreme. In order to avoid extremely hight intensities, this option allows the user to tonemap the resulting black body color.
Specular Parameters¶
- Specular Amount
- The intensity of the specular term.
- Specular Roughness
- The apparent surface roughness of the specular term.
- Index of Refraction
- Absolute index of refraction
Note
This term is a simple dielectric specular term using the GGX [heitz:hal-00996995] microfacet distribution function, with energy compensation for high roughness values.
Bump Parameters¶
- Bump Normal
- The unit length world space normal of the bumped surface.
Matte Opacity Parameters¶
- Enable Matte Opacity
- Parameter that toggles matte holdouts.
- Matte Opacity
- Matte opacity scaling factor.
- Matte Opacity Color
- Holdout color.
Advanced Parameters¶
- Ray Depth
- The maximum ray depth a ray is allowed to bounce before being terminated.
Outputs¶
- Output Color
- The combined EDF+BRDF output color.
- Output Matte Opacity
- The matte holdout.
- Output Blackbody Color
- The black body radiator color.
Screenshots¶
References
| [HDEon14] | Eric Heitz and Eugene D’Eon. Importance Sampling Microfacet-Based BSDFs using the Distribution of Visible Normals. Computer Graphics Forum, 33(4):103–112, July 2014. URL: https://hal.inria.fr/hal-00996995, doi:10.1111/cgf.12417. |
| [WW11] | A. Wilkie and A. Weidlich. A physically plausible model for light emission from glowing solid objects. Computer Graphics Forum, 30(4):1269–1276, 2011. URL: http://dx.doi.org/10.1111/j.1467-8659.2011.01986.x, doi:10.1111/j.1467-8659.2011.01986.x. |