the 3d map is not very good

hi, when i use rtabmap_ros and bumblebee2 to build a 3d map, I found that my map is not very good as the stereo-mapping- outdoor-demo.For example, when i try to build a 3d point map for a table , I found that in the middle of the table there has a hole and it was not smooth just like missing a block of the table. The launch file i used were stereo_mapping.launch and bumblebee.launch and all of these is from rtabmap_ros file. So ,what should i do to change the result and have a better result?? I'm so appreciate for your answer !!Your answer is very important!! Thank you very much!