UV map saturn rings in Mantra

[Alexandre]

Hi houdinist !

I am trying to apply saturn ring texture in mantra but I failed to reproduce the texture mapping in attachement (done in blender),

someone could help ? I tried to rotate UV by an angle of 90° over each face, but I don't know how to achieve this

hip file in attachment with saturn ring texture

thanks

Alex

 

ring.hipnc

[Alexandre]

here is how it's done in blender but can't find a way to reproduce it in houdini (https://blender.stackexchange.com/questions/92812/how-can-i-assign-an-image-texture-on-a-circle)

[Alexandre]

using the facet node I managed to split polygon,

now I messing with UVs nodes

[Alexandre]

well it's working just stay on facet node

[konstantin magnus]

You can turn a wide grid into a ring using sine and cosine on the bounding box of the grid. That way you can also create UVs on the fly.

float radius_inner = chf('inner_radius');
float radius_outer = chf('outer_radius');

vector bbox = relbbox(0, v@P);
vector bbpi = fit01(bbox, -M_PI, M_PI);

vector uv = set(bbox.z, bbox.x, 0.0);
v@uv = uv;

vector pos = set( cos(bbpi.x), 0.0, sin(bbpi.x) );
pos *= fit01(bbox.z, radius_outer, radius_inner);
v@P = pos;

 

saturn_rings.hipnc

[CinnamonMetal]

@konstantin magnus Where did you get M_PI ?

[jkunz07]

36 minutes ago, CinnamonMetal said:

@konstantin magnus Where did you get M_PI ?

#include <math.h>