some question about noise for a shape

[cloudfx]

Let say if I want a sphere to have some natural shape, I fetch position data of point or voxel to turbulence vop and add that to my global position ,right?

I saw 1 example and he get the vectors which is shooting from center of the sphere to the current positions (basically shoot from inside to outside) and normalized the vector and multiplied to the turbulence value before adding the value to the global position.

I've heard that is to make give turbulence value only for the edges of the sphere but how that actually work out?

Edited October 2, 2012 by cloudfx

[DanBode]

It's usually done to give a directionality to the displacement. If you just add a noise vector to P the surface can move in any direction, but if you take a float noise and multiply it by a normalized vector, the surface will always be displaced in the direction of the vector. Since the vectors used in that example vary gradually you get a much smoother noise than you would if you just added a random vector.

For a simple example throw down a grid and two vopsops. In one vopsop add a vector noise to P, in the other multiply a float noise by the normal and add that to P. This will show you the difference between the two methods.

[cloudfx]

It's usually done to give a directionality to the displacement. If you just add a noise vector to P the surface can move in any direction, but if you take a float noise and multiply it by a normalized vector, the surface will always be displaced in the direction of the vector. Since the vectors used in that example vary gradually you get a much smoother noise than you would if you just added a random vector.

For a simple example throw down a grid and two vopsops. In one vopsop add a vector noise to P, in the other multiply a float noise by the normal and add that to P. This will show you the difference between the two methods.

Thanks for the well explanations.

I understand the directionality of turbulence for the points.

Howeber, for volume, what would be main benefit with multiply normalized position data of voxel to turbulence and add to position to get distance and remap(fit) for getting edge smoother

and

just multiply turbulence with position data of voxel and get distance and remap(fit) for getting edge smoother?

I don't see much difference.