Transparency parameters

These options determine the transparency of materials. (For example, glass is more transparent.) Hardware rendered materials with colored transparency and a strong diffuse color can exhibit dramatically different color results when semi-transparent. To work around this, use either 100% transparency or grayscale diffuse colors in hardware rendering. Ray Tracing will render colored semi-transparency correctly.

Use Color

Click the color swatch to change the color. For details on how to use the Color window to choose a color, see Change colors. Use the slider to adjust the transparency setting. Move it to the right for more transparency and move it to the left for more opaqueness.

Use alpha from ‘Color’ image file for transparency

If you have used an image map in the Color parameters and if that image has an alpha channel, click this button to use that alpha channel to control the surface transparency.

Using the alpha from the color image file helps you keep the color and transparency maps aligned. As you move the color map, the transparency map will stay aligned with the color map pattern.

Use image file

Use a unique image as a transparency map.

Transparency maps determine which parts of an object are opaque and which parts are transparent. They can be used for materials with holes punched out such as a metal grill or perforated rubber. Darker areas of the transparency map produce an opaque material, while brighter areas create a more transparent appearance.

Invert transparency texture

Reverses the transparency of a defined image file. What was fully transparent will then be fully opaque, and so on. Identical to opening the transparency image file in an image editor and inverting the colors.

Block transparency highlights

Block highlights and reflections for all areas that are 100% transparent. Useful for simulating holes in solid surfaces.

For details on how to use these controls, see Use image maps.

Ray Tracing Properties

Material transparency properties that are unique to the Ray Tracing display and rendering mode. These settings will have no effect on the material when viewed in Hardware rendering mode.

• Refractive Index: the physical property determining how much refraction (visual distortion in transparency due to bending light) is present when transparent. A value of 1 will result in no refractive distortion at all.

  Refraction is respected by geometry environments, but not scale-independent (backdrop) environments. In other words, if your scene contains glass with refractive properties, the portion of a geometry environment behind that glass would be distorted due to the refraction. A scale-independent environment would not be distorted. For accuracy, use real-world values (such as 1.56 for glass, and 2.2 for diamonds) whenever possible. Refractive indices are common to all materials, and lists of real-world values can be found on the internet very easily.

• Use absorbance: toggles absorbance coloring and transparency attenuation. Absorbance is the visual effect of light being absorbed as it passes through a material, which is a physically accurate version of a transparency color. The greater the depth of the material, the more light is absorbed, so transparency becomes less.
• Absorbance color: the color of the material transparency when the absorbance depth is reached or exceeded.
• Omit transparency color: toggles the use of the main transparency color for both color and transparency amount. Uses only absorbance to calculate the color and amount of transparency for the object.
• Absorbance depth: the thickness at which the Absorbance color is achieved for overall transparency. At depths less than this amount, the transparency approaches 100% transparent in a gradient.
• Simulate thickness: Used to add depth-based effects such as refraction and absorption to transparent objects that are created as a single, infinitely thin surface.

  Simulate Thickness will "shift" the rays passing through the object to show refraction and absorption as if there was a second, identical surface at the specified depth behind the actual transparent surface. However, the ray tracing effects will not be as accurate with simulated thickness as they would be with true thickness. This simulation looks best when adding very small amounts of thickness to single surfaces, such as windows.

  Note

  Note: Artifacts can appear in Ray Tracing when simulate thickness is used and the surface actually has true, modeled thickness, or the amount of simulated thickness extends "into" a nearby object or the ground plane. In these cases, it is better to use an accurate model with the thickness built into it.