# Calculate initial velocity of a 3d vector-based projectile

Okay, so I got a Projectile with 2 Vectors, position and velocity. I now want to calculate the initial velocity for it in order to reach a specific point on the map.

Or actually, how high has the start z-velocity to be (because x and y are probably defined by a speed variable) in order for the projectile to hit the marked position.

The projectile is influenced by a constant gravity vector.

All calculations are done 32 times per second.

I want this, because I don't want to use a parabola function, so the projectile can still be influenced by other sources, simply adding some velocity.

I didn't really find anything referring to that topic and would be glad for every helping answer, Thanks.

• What can influence your projectile while it is traveling? Gravity? other effects? Without knowing those factors we can't give you anything :) – Roy T. Jul 1 '12 at 20:05
• oh, sry. The only influence is a gravity vector. – Frotty Jul 1 '12 at 20:40