Rotate flat geometry to X/Z plane. Houdini VEX.

align_to_normal.vex

// Align object to target vector base on selected normal
// Useful when object has some weird orientation baked 
// in the mesh and you wan to straighten it up.

// Point with normal from second wrangler input to align
vector from = point(1, 'N', 0);

// Allign "from" normal to the following vector
vector to = {0,1,0};

matrix3 m = ident();
float amount = acos(dot(from, to));
vector axis = normalize(cross(from, to));

rotate(m, amount, axis);

@P = @P * m;
@N = @N * m;

Thanks a lot. you save me

@yjsp93 glad it is useful.

It works very good, thx a lot!