The Pattern Transparency tool, from the application toolbox, can be used to create and interactively edit tiling pattern transparency masks on objects and group of objects. The pattern transparency tool works in a same way as the Pattern Tool.
Pattern Transparency Tool
To create a pattern transparency, select the Pattern Transparency tool from the application toolbox (located in a group with the pattern tool). Click on the object and start dragging. The transparency mask will be created with the current tiling pattern content. Adjust the extent and rotation of the pattern tiles by dragging the tile handles.
The tiling pattern content must be selected from the pattern panel, using the list of available pattern contents. New pattern content can be created by creating new symbols, or creating pattern styles and presets from objects.
The tiling pattern attributes of a transparency mask can be edited from the pattern panel. To create or edit pattern transparency masks from the pattern panel, select the Transparency option in the Mode field. All the options edited in the pattern panel are applied to the transparency mask of the selected objects. For details on using the pattern panel see the Pattern Panel section.
The pattern transparency mask can also be set from existing pattern styles and presets. This can be done either by selecting the style of preset in the Type field of the Transparency panel, or by using the Styles or Presets panels. In the Styles or Presets panels, the Mode field is active when a style is selected that can be used as a fill, stroke or transparency style. Select the Transparency mode from the Mode field and double click on the style in the panel to select it as a transparency style.