Here’s a straightforward question for Unity EXPERTS.

Say you have two rigidbodys a and b and they have velocities. (Obviously a.velocity and b.velocity )

What is the **usual idiom in Unity, to calculate** the velocity of b, **as seen from** a ??

I assume the answer is simply:

```
var speedOfBSeenFromA:Vector3;
speedOfBSeenFromA = b.velocity - a.velocity;
```

Is this correct?? **Can an expert please confirm this?** Maybe there’s something I don’t understand about Unity?

Once again, of course I know how to add “actual” vectors in Newtonian space, as in high school physics class. My question is specifically: **what is the usual Unity idiom**? Thanks!

To be clear, by “relative velocity” I simply mean as any high-school physics teacher would think of it! For example: imagine B is heading “straight up” at 10 m/s, and A is heading “straight down” at 2 m/s. In this case, essentially 10 - (-2) = +12, which seems correct.

Note: it seems somewhat odd there is not a function “relative velocity” since it’s so common, maybe I’m missing something? (I realise it’s just one minus the other - maybe that’s the reason they didn’t include such a function?)

Note: there is the somewhat confusing function **GetRelativePointVelocity** which appears to give the velocity of something passing seem from a strictly **stationary** point. (Assuming I understand that function correctly.)

So, I appreciate a **seasoned expert** letting me know if I’m correct in that the answer is very simply b.velocity-a.bvelocity. thanks!

PS no need to calculate Einsteinien time dilation for velocities approaching c !!