Hi Tully,

The problem was that I wasn't naming my topic /foo_array.  I had 
incorrectly assumed that rviz would detect from the type of the topic 
whether to subscribe to it as Marker or MarkerArray.  Subscribing to /foo 
in rviz while publishing to /foo_array in my ROS node works correctly 
(although I find it a bit counterintuitive).  Thanks for your help!

  -ross

On Sun, 9 Jan 2011, Tully Foote <tfoote@willowgarage.com> wrote:

> Ross,
> Can you explain a little more about what your setup is?  I notice that
> neither of your md5sums match with the ones on my system.  Do you have local
> changes?
>
> Also from the plugin topic menu I see.
> {{{
> visualization_msgs::Marker topic to subscribe to. _array will also
> automatically be subscribed with type visualization_msgs::MarkerArray.
> }}}
> This might take care of your problem.
>
> Tully