This video shows you how to create an HDA that culls points outside the camera frustum using vex instead of using a volume.
I originally recorded an example of how to crash your scene by using a volume, but I cut it out because I didn't want to bore everyone to death.
Addition: I missed to check if the points are in front or behind the camera in the video, but you can solve that easily by checking the z value. It would look something like this:
"if((campos.x+padding.x) ＜0|| (campos.x-padding.x) ＞1 ||(campos.y+padding.y) ＜0 || (campos.y-padding.y) ＞1 || campos.z ＞0)"
