here's C++:

float x = x1 - x2;
float y = y1 - y2;
float z = z1 - z2;

distance = sqrt(x*x + y*y + z*z)

Thanks for your quick response Mutex.

Anyone know how to calculate the length of a line in 3D when you know the endpoints.

Like (x1, y1, z1) and (x2, y2, z2).

Thanks!

Remember, however, that for many applications of the distance function (checking for collisions against bounding spheres, etc). You can usually get away with using the "distance squared", and avoid doing the (SLOW!) square-root operation.

i.e.: if you have two billiard balls which are 2 units in diameter, to see if they collide, you can check to see if their centers are within 4 units of each other, avoiding a square root operation.

-- Pryankster