Environment Alpha Toggle and Filtering

To control whether the renderer uses the environment map's alpha channel in creating the alpha for the rendered image, choose Customize Preferences Rendering, and then turn on Use Environment Alpha in the Background group.

If Use Environment Alpha is off (the default), the background receives an alpha value of 0 (completely transparent). If Use Environment Alpha is on, the alpha of the resulting image is a combination of the scene and the background image's alpha channel. Also, when you render to TGA files with premultiplied alpha turned off, turning on Use Environment Alpha prevents incorrect results.

You can also control whether a background image is affected by the renderer's antialiasing filter. Choose Customize Preferences Rendering, and then turn on Filter Background in the Background group. Default=off.

Tip: If you plan to composite 3ds Max objects in another application such as Combustion or Photoshop, render the objects against a black background. Otherwise, a fringe of environment or background color can appear around the 3ds Max objects.