How to playback pointcloud in rviz which was recorded using rosbag

edit

Thanks fergs! It works! btw, it should be " /user_sim_time"

No, it should be use_sim_time, just as @fergs wrote.

sorry~~my fault, should be "use_sim_time" or "/use_sim_time" ,both are fine

Do you mean that first 'rosparam set use_sim_time true' and then run rviz and then 'rosbag play name_of_bagfile.bag --clock'? I do the same procedure but cant play back the data. Furthermore, my rosbag record just record only 2 seconds for the kinect. How can I fix it? Thanks a lot.

Yes, rosrun rviz rviz after setting param true. What I do is,run as above, quickly set the topic, then run the bag again and the topic will show as expected inside rviz. You have a bag that was recorded for 2s - dont set the time and you can record as long as you like: rosbag record -O subset /topic