Transparency (CineRender Surface Channel)

Here you can define the transparency, including a refraction index.

Use the Color and/or Brightness parameters to set a transparency. Using a 50% gray is similar to using white and 50% brightness.

Color percentage + Transparency percentage = 100%

Surface Color	Transparency Percentage	Result
White surface	zero transparency	Totally White (100% white)
White surface	50% transparency	Gray (50% White)
White surface	100% transparency	No color

If the surface has a color (in the Color channel), the color is automatically reduced with increasing transparency.

Tip: Much better results can be achieved if Absorption is used (see Absorption, below).

You can load a texture as a transparency map. The brighter a pixel in the transparency map, the more transparent the corresponding region of the surface. A transparency texture is similar to a photographic slide: Red parts of the slide allow only red light to pass through; white parts allow all light through. With black, no light can pass through the slide.

Color and Brightness

See Defining Color and Brightness Values.

Refraction

You can simulate the refractive index by setting the Refraction value.

Useful refraction values

Obsidian 1,480 - 1,510

Amethyst 1,544 - 1,553

Emerald 1,576 - 1,582

Diamond 2,417 - 2,419

Glass noodle 3,999

When a ray hits a closed surface (leftmost image, below) with transparency and refraction, the ray is bent to simulate refraction. The bent ray is considered to be inside the object. When the ray reaches another surface of the object (the exit side), it is bent back as in real life.

However, if the object is open, the ray may not hit a second surface of the object (center image, below). Thus the ray may not be bent back and the refraction effect may be inaccurate.

For this reason, ensure that all transparent surfaces in the scene are closed (as in the right-side image below).

If you are using refraction with windows - with the refraction parameter other than 1 - the glazing must be closed (that is, you must use an even number of panes). (In ARCHICAD, to improve 3D generation speed, glass panes are modeled as surfaces that have no thickness.)

Total Internal Reflection

Enable the Total Internal Reflection option to activate the Fresnel Reflectivity effect (see below). This will automatically reduce the transparency and increase reflectivity when the surface is viewed at an angle. This is a common and physically correct characteristic of glass and should therefore not be disabled for glass.

Note that the reflective properties (e.g. Roughness) can be fine-tuned in the Reflectance channel’s *Transparency* setting.

See *Transparency*.

Exit Reflections

As soon as a Reflection meets a surface after being refracted through glass one of two slightly different reflections can be calculated - ones that result when they enter glass and those that exit the glass. A single reflection is often visually the most appealing one (even if it is in fact false). To achieve this effect, disable the Exit Reflections option.