 float T_2 = t_0 * N_1;
 float periods = periodCount-1.0; // 26 // number of patch periods along surface
 float Omega = ((N_1/N_2)*2.0*PI)/t_0; // (N_1/N_2)*2*PI/t_0, before 8.0*PI*pow(10.0,7.0);
+
+
 //float bias = (N_2/2.0)/(N_2-1.0); // old: 50.0/99.0;
-float bias = (1.0/(N_1-1.0))*((N_1-1.0)/2.0); // old: 50.0/99.0;
-//float bias = 0.5; // old: 50.0/99.0;
+
+
+// for 99 works fine
+//float bias = (1.0/(N_1-1.0))*((N_1-1.0)/2.0); // old: 50.0/99.0;
+float bias = 0.5; // old: 50.0/99.0;
 
 
 float neighborRadius = (neigh_rad < 5 && neigh_rad > -1) ? float(neigh_rad) : 0.0;

	vec2 N_uv[2] = vec2[2](N_u, N_v);
	vec2 modUV = getRotation(u,v,phi);
	
	float uv_sqr = pow(u*u+v*v, 0.5);

	float iterMax = 300.0;
	float lambdaStep = (lambda_max - lambda_min)/(iterMax-1.0);
	float F2 = fFByR0*fFByR0;
	

	}
	
	// relative Fresnel Factor
	float F = fFByR0;
	F = F*F;
//	float cosNumNumSamples = cos(thetaR)*dimN*dimN;
	float cosNumNumSamples = 1.0;
