vector explanation

Ok, I have been trying to get my head wraped around this and I am not having much luck. From the wiki a vector is comprised of three floats. Which can map well to a point in 3D space. What I am missing is how a vector describes force, impulse, and velocity. The wiki is not very helpful on explanations other than they are pysical properties (relating to physics).

Is this simple or am I trying to over think things.

Thanks

If you can imagine a point in 3D space, then imagine a line drawn from the origin (which is <0,0,0> to that point. This line has a defined direction and a defined magnitude. Thus, it can represent a force, because has all the information needed to say "push so hard in this direction".

In general, a vector is a magnitude and a direction. Representing it as 3 floats is one way of expressing this information. And it does map very intuitively to a point in 3D space. But it's still a vector. If you start visualizing that point as a line from the origin to that point, that might help you see how vector addition etc. works for velocities and forces.

So let's say you have 2 forces acting on an object - <a,b,c> and <x,y,z>. The combined net force is the vector addition of these two. But if you want to visualize it, think of <a,b,c> as a line of a certain length pointing in a certain direction, and <x,y,z> as another line, also with length and direction. Now you need to "add" these lines together. So you take an empty 3D space, and put the first line down, starting at <0,0,0>. Obviously, the other end of the line is at <a,b,c>, since that's your vector. Now you take the other line and "add" it to this line - put the start of the 2nd line at the end of the 1st line. This line will now end somewhere. The final vector is the coordinate of this end point. It is also the distance from the origin to this point. You can view it in either way.

To take a more concrete example - if <a,b,c> is say <1,0,0> (so 1m east) and <x,y,z> is <0,1,0> (1m north), then if you "add" these lines together, you'll end up with a point that ends at <1,1,0>. Which is a 1.4m line that points north-east. So, you can represent the same information in 2 ways - as a coordinate <1,1,0>, or as a direction/magnitude pair - 1.4m north-east. Either way, it's still a vector, so it can describe a point, or a velocity or a force or whatever.

Hope that helps somewhat I know it's vague. But it's hard to describe how someone understands something, especially concepts like these.

When dealing with velocity(like with llGetVel()), the vector is the speed in meters per second the object is moving along each of the three axis. For force and impulse, it is the pressure on the object that will try to move it at the set meters per second.

So if you use llSetForce with <2, 3, 0>, it will try to move the object at 2m/s along the X axis, and 3m/s along the Y axis(about 3.6m/s total). llSetForce is a constant force that will only stop when set to <0,0,0>, though it won't have any effect if the object is not physical. llApplyImpulse is similar, but is a one-time effect that dies instantly.

That accually helps. Going back over it with these explanations do help. I was trying to over think it.

thank you.