Varying material opacity

Variable opacity is supported for solid color and repeatable textures applied to overlapping objects, as well as for decals and window-covering materials.

Opacity information can be provided simply by using an RGB image with an alpha channel. In addition, the overall opacity can be varied with the opacity= command (both for RGB and RGBA images).

Wall borders also support RGBA images, primarily to support die-cut borders.

The vnw files which define window-coverings can include an opacity channel. It is combined by the renderer with the alpha channel of the repeatable texture and the opacity= value to provide a full range of opacity effects for sheer and translucent window treatments.