A texture that always maintains its alignment to the [[Viewer¹|viewer]], and often is scaled up and down to place it in the 3d scene. This is a common device to get more detail in objects without using a lot of polygons. However, they are flat and look strange when you move around them. They can be set up to rotate on only one axis or on combinations of the [[RotationalAxis|three rotational axes]], for different alignment effects. For example, if you want to do a tree, rotate only on the verticle axis. If you want to have an object always stay plastered upright on the screen, have it use all three axes. Billboards are [[Transforms|transformed]] in world space and aligned to the viewer, whereas [[Sprites|sprites]] usually stay flat to the viewer, like interface graphics. A cool trick is to use a curved billboard, which helps give more depth to a single-axis billboard, because like a tree billboard, you can look down on it, so the extra depth helps get rid of that flat look. Also called a Flag, Kite, or Stamp.