HI,
I have a problem.
I would like to learn how to interpolate a vector(cubic).
Big problem:

Most things/documentations on the web are just like a dschungle and its not easy for me to understand them. I have never been that bad in math, but cubic interpolation is eating my brain.

Maybe someone can help me?(tips, help, advice, explanation)

Greets
Rackscha

"how to interpolate a vector(cubic)"

What are you trying to do? I don't get it.

i think its.. getting the half on the distance of 2 axis vector i mean cubic-> xyz i think..

no,
Cubi is a interpolation method

CUBIC, QUADRATIC,LINEAR

i have 2 positions, and want to interpolate a vector between them(cubic)

§dgs only has a linear interpolation function

may i ask the differencec?

Doesn't a cubic interpolation require four nodes/vectors to interpolate, or the tangent vectors at the positions of the two nodes? Just two nodes isn't enough information for a cubic interpolation.

@Lukas:
Thats right, but in one example someone just placed 2 vectors between them.
(depending on the start and end velocity)

But maybe thats not a clean way.

What iam trying to do is to interpolate positions between multiplayer entities as smooth as possible(objectets speeding up and down).

For example:
i wnat to scale a vector between the old and the new position. But i dont want it to be done linear. Scaling has to be done slow at the beginning and fast at the end.(within a given number of frames)

So lets say i want to interpolate between 5frames, i wnat the scaling to be at 100% on the 5th frame but not linear between 1-5th frame.

vec_lerp(v,v1,v2,smooth(f))

var smooth(x)
{
return x*x*(3-2*x);
}

i sometimes use cos() for easing in/easing out the interpolation. could work for you too.

and i had big problems with vec_lerp() because of the insufficient var precision so i did my own version that uses floats. it's much smoother.

If it's just about having a certain start and end velocity, how about just using vec_lerp and raising the interpolation factor quadraticly?