3-D Visualization

Specifying Transparency

Transparency values, which range from [0 1], are referred to as alpha values. An alpha value of 0 means completely transparent (i.e., invisible); an alpha value of 1 means completely opaque (i.e., no transparency).

MATLAB treats transparency in a way that is analogous to how it treats color for the respective objects:

• Patches and surfaces can define a single face and edge alpha value or use flat or interpolated transparency based on values in the figure's alphamap.
• Images, patches, and surfaces can define alpha data that is used as indices into the alphamap or directly as alpha values.
• Axes define alpha limits that control the mapping of object data to alpha values.
• Figures contain alphamaps, which are m-by-1 arrays of alpha values.

See the following sections for more information on color:

• Specifying Patch Coloring in the "Creating 3-D Models with Patches" chapter.
• Coloring Mesh and Surface Plots in the "Creating 3-D Graphs" chapter.

Transparency Properties

The following table summarizes the object properties that control transparency.

Properties	Purpose
AlphaData	The transparency data for image and surface objects
AlphaDataMapping	The transparency data mapping method
FaceAlpha	Transparency of the faces (patch and surface only)
EdgeAlpha	Transparency of the edges (patch and surface only)
FaceVertexAlphaData	Patch only alpha data property
ALim	Alpha axis limits
ALimMode	Alpha axis limits mode
Alphamap	Figure alphamap

Transparency Functions

There are three functions that simplify the process of setting alpha properties.

Function	Purpose
alpha	Set or query transparency properties for objects in current axes
alphamap	Specify the figure alphamap
alim	Set or query the axes alpha limits

Making Objects Transparent

Specifying a Single Transparency Value