The create button will generate an imposter according to the create parameters. The rotation of the imposter is only default when created, so you must first rotate it to the desired position. For branches only the y-axis has any effect so make sure you are using the y-axis (green) gizmo. Once in position the update button will conform the polys to the bounding limits of the geometry. If this is a branch it will conform the polys along the branch also. Render will then render imposters to from the normal direction of the polys.

The Display check box will enable the display of imposters even when the sub object is not longer set to imposter.

The Rendered check box will enable imposters to be rendered. This will allow for considerably less nodes in max, because when a parent creates its imposter if the child branches are rendered imposters they do not all need to have their complete hierarchy.

Some new features have been added with version 2. These include the AA filter check box. It has been added because often when rendering imposters from other imposter you loose resolution, adding some anti-aliasing to the texture prevents the imposter from become too transparent.

Another new feature is the ability to inherit child imposters. This enables a child imposter to be drawn with its parent imposter. This may be useful if a child branch would require its own imposters, inheriting would then remove the need for having essentially the same imposter geometry twice.