Why does the velocity add so much more size?

[Jordan]

you shouldn't need 4 floats for direction and length, a 3 value vector gives you direction and length. Unless you are using a 3 float unit vector and a length float, but this would just be a waste of space!

Well when you are looking at a 10 fold size increase on jobs that are going to take up 10Tb + then it does matter quite a bit!