RE: [Algorithms] interpolate between points in 3d space

[Steve W. <Ste...@im...>]

When a projectile is fired you should use it's trajectory equation. It
sounds like you are entering the realm of physics. I'll give you a clue, but
please pick up a book on newtonion physics, browse the web for physics
stuff...there's been many references to physics web sites on this
list...unfortunately we don't have an archive that goes back far enough
right now that I know of.  Maybe someone will post a link or two for you.

Anyway for your particular example...let's add a mild constant wind
resistance Wz and Wx along Z and X axis:

X0 = initial X position of fodder after it leaves the cannon.
Y0 = initial Y position of fodder after it leaves the cannon.
Z0 = initial Z position of fodder after it leaves the cannon.
Vx0 = initial velocity in X direction of the fodder after it leaves the
cannon.
Vy0 = initial velocity in Y direction of the fodder after it leaves the
cannon.
Vz0 = initial velocity in Z direction of the fodder after it leaves the
cannon.
Wx = constant wind resistance
Wy = constant wind resistance
Wz = constant wind resistance
g = acceleration of gravity
t = time with zero when the fodder leaves the cannon.

X = X0  +  Vx0 * t  -  Wx * t                 //X position
Y = Y0  +  Vy0 * t  -  Wy * t  -  .5g * t^2   //Y position
Z = Z0  +  Vz0 * t  -  Wz * t                 //Z position

That's pretty much it, except you may want to use vector math instead of
breaking it up into parts like I did.  Did this answer your question?

R&R

> From: Anceschi Mauro [mailto:anc...@li...]

> Hi.
> I have a little problem in my 3D space game.
> When my ship "fire" from a cannon i use a new local axis for 
> the new object i'm firing , for calculate the next point of the laser.
> But this works bad, and i  don't have much precision.
> So my question is:
> How can interpolate from 2 point in 3d?
> (x,y,z) and (x',y',z') (suppose the second is an enemy ship).
>  
> Thanks,
>  
> mauro