     Cm = Rs - T121p;
     for (int m = 1; m <= 2; ++m){
         Cm *= r123p;
-        Sm  = 2.0 * evalSensitivity(float(m) * D, float(m) * (phi23p + phi21p));
+        Sm  = 2.0 * evalSensitivity(float(m) * OPD, float(m) * (phi23p + phi21p));
         I  += Cm * Sm;
     }
 


    vec3 xyz = val * sqrt(2.0 * PI * var) * cos(pos * phase + shift) * exp(-sq(phase) * var);
    xyz.x += 9.7470e-14 * sqrt(2.0 * PI * 4.5282e+09) * cos(2.2399e+06 * phase[0] + shift[0]) * exp(-4.5282e+09 * sq(phase[0]));
    return xyz / 1.0685e-7;
}

/* Polarized Fresnel Term

    }

    // Optical Path Difference
    vec3 OPD = 2.0 * eta_2 * Dinc * cosTheta2;

    // Variables
    vec3 phi21p = vec3(0.0);
