Thread Subject: calculating velocity in 3D space

> something like:
> sqrt((x0-x1)^2+(y0-y1)^2+(z0-z1)^2)/(t1-t0)

Of course, this would give you more of a speed, rather than a
velocity, since you don't have a direction... but if you wanted to
find it with direction, all you need to do is to do a single
differentiation in each axis separately. If you have a vector of
points for each axis, you could use the diff command