I'm still trying to figure it all out. If you look at the properties of a Newton object you usually see 'collision_groupid' right? Whatever that number is the Newton object will only collide with that group number. If you want the object to collide with everything make they all have the same number. If you want the Newton object to ignore a block or entity, simply change their group id number. I don't know how to change the ID of blocks. Hope that helped.