Alpha Threshold

iClone provides Alpha Threshold settings for objects with Opacity textures. When you apply a grayscale image to the opacity channel, you may encounter some issues with earlier version of iClone. However, with the Alpha Threshold setting, these artifacts can be removed.

The artifacts caused by grayscale opacity texture

Alpha Threshold uses the opacity texture to trim props. Shadows will then be altered as the prop changes look. Although the shadow result may look the same as the Shadow Threshold does, the prop appearance will actually be different.

The benefits of using the Alpha Threshold feature are:

• Increasing real-time speed and performances
• Fixing undesired edge lines from objects
• Removing illogical outlines from character's hair

Increasing Real-time Speed and Performances

• If you apply an grayscale image for the Opacity channel to create a transparent prop, then the program always calculates the transparent, the semi-transparent and the opaque areas.

  Gradient opacity image Alpha Threshold = Off

• If the prop contains no semi-transparent part, such as a chicken wire or fence, then you can enable the Alpha Threshold and adjust the value to skip calculating the semi-transparent parts.

  Black and white opacity image Alpha Threshold = On

• This method increases the playback speed and performance.

Fixing Undesired Edge Lines from Objects

• When you use the Opacity channel to produce a partial transparent object, then you may find edges around the object.

  Alpha Threshold = Off

• By activating the Alpha Threshold setting and adjust the slider, you may then eliminate these annoying edges.

  Alpha Threshold = On

Correcting Character's Hair for Toon Shader, and NPR Post Effect

• Each character's hair contains Opacity textures, which may cause incorrect Toon Shader or NPR results. By activating the Alpha Threshold box of the hair, the visual artifacts can be removed.

  Alpha Threshold = Off	Alpha Threshold = On