Adding and Editing Textures in Appearances

You can add a 2D image as a texture to an appearance. When you apply an appearance with textures to a part in a model, the textures are mapped on the part according to the texture properties.

1. In the Palette, on the Appearances tab, select an appearance in the Appearance tree.
2. Under Texture, double-click the Color, Specular, Alpha, or Bump channel.

   For a 2D image, a channel is a sub-image composed only of the values for a single component of a given pixel. A grayscale image has one color channel, an RGB image has three, and a CMYK image has four. When applied to appearances, the term refers to one particular subset of the properties which determine the way in which a surface reacts to light, including color, reflectivity, transparency, diffusion, specularity, and bump.

   Alternatively, you can drag a 2D image from your desktop, email, or similar source, to the part in a model in the project. Then you can select which channel to apply the texture to. With Color textures, non-transparent appearances can use a 2D texture instead of a base color. However, some types of appearances, such as Emissive, multiply the base color by the Color texture RGB values. If you add an Alpha texture with transparency, only the transparency channel in the Color texture is used.

3. In the dialog box, browse to select a texture.
   You can select any 2D image in the following formats:

   • .JPEG
   • .GIF
   • .TIFF
   • .BMP (Bitmaps)
   • .TGA (Targa)

   If the texture contains transparency, you must use the .PNG format which supports an alpha channel. The alpha channel is the top byte of a 32-bit pixel that is used for data other than color. The alpha channel commonly holds mask data so an image can be separated from its background for use in compositing.
4. To see the texture's parameters, do one of the following:
   • In the Appearance tree, select the appearance icon.
   • Click Selection Tool > Appearance and select a part to which the appearance has been applied.