@Amber-Elaine-Parker It's missing a TF. After launching ROS Indigo on the VOXL, open a new bash and type:

rosrun tf static_transform_publisher 0 0 0 0 0 0 1 map world 10

This is enough to create the world frame and make the ToF sensor PointCloud2 message display on Rviz (if you select the world frame under global options in Rviz). However, it looks like the frame isn't oriented correctly in my case. Editing the parameters of this command might change the orientation of the new world frame.

I don't know enough about ROS/VOXL SDK to confidently call this an oversight by the ModalAI team, but there should definitely be a mention that this is required somewhere within the documentation.