Noise Direction question

[midicon]

Does anyone know a way to get noise on a animated sphere that to offset in opposite directions from the center? I have attached an image of what I'm talking about. any help would be much appreciated. Thanks

[vtrvtr]

What about clipping the sphere in the middle and then using the mirror sop to mirror it? 

Like this

 

Edited January 9, 2017 by vtrvtr
Added image

[MENOZ]

you could squash and translate it's "rest position" and feed it in the noise texture

[woodenduck]

In an attribute vop, take a 'relative to bounding box' vop and run this through a 'compare' vop set to greater than 0.5. You can plug the result of the 'compare' in to a 'switch' vop with time and negated time as the 2nd and 3rd inputs. Plug that in to the x component of a 'float to vector' vop and plug the result in to the offset of your noise vop. You should see the noise on one half of the sphere moving in positive x and the other half in negative x. 

[mestela]

I love these sorts of challenges.

Made some rotating uvs so the noise flows around the shape rather than just slides in a wrangle, then drive noise with those uvs.

float t;
matrix3 m = ident();

v@uv = @P;

// set speed
t= @Time*ch('speed');

// get coords that are centered and mirrored on x
@uv = (0.5-relpointbbox(0,@uv));
@uv.x = abs(@uv.x);

// rotate coords around the y axis
rotate(m, t, {0,1,0});
@uv *= m;

mirror_rotating_noise.hip

[midicon]

Both of these are great solution! thanks so much for getting back to me! 

[konstantin magnus]

Hi Rob, there is a VOP node to convert your position into polar coordinates.

polar_noise.hipnc

[f1480187]

I wonder, if it's possible to offset polar coordinates' radius with periodic forms of noise, so, the noise infinitely goes outwards without scaling. I had no luck with it.

[mestela]

dur me, polar coords is a much neater solution. twiddled it so it gives clean 0-1 co-ords so you can map images and stuff too.

rot_uvs_polar.hip