RE: [Algorithms] interpolate between points in 3d space (correcti on)
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From: Steve W. <Ste...@im...> - 2000-07-21 19:09:55
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Oops...forgot to mention...the wind resistance in the Y direction changes sign after the fodder has started it's way down...so it would be the opposite sign of the sign of the Y velocity: Wy = Wy * -sgn(Vy) Where Vy = Vy0 - g * t R&R > -----Original Message----- > From: Steve Wood > Sent: Friday, July 21, 2000 11:48 AM > To: 'gda...@li...' > Subject: RE: [Algorithms] interpolate between points in 3d space > > > 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 > |