diff --git a/kernels/UnravelHeart3D.hpp b/kernels/UnravelHeart3D.hpp
index 72a81e6..8c1eb90 100644
--- a/kernels/UnravelHeart3D.hpp
+++ b/kernels/UnravelHeart3D.hpp
@@ -20,9 +20,12 @@ public:
 		vectorNew[1] = parameters[2]*(vectorOld[0] + parameters[3]);
 		vectorNew[2] = parameters[4]*(vectorOld[1] + parameters[5]);
 
-		const double dist = vectorNew[0]*vectorNew[0] + vectorNew[1]*vectorNew[1] + 2.0*vectorNew[2]*vectorNew[2];
+		const double x = vectorNew[0] / parameters[6];
+		const double y = vectorNew[1] / parameters[6];
+		const double z = vectorNew[2] / parameters[6];
+		const double dist = x*x + y*y + 2.0*z*z;
 
-		if(parameters[7] * dist - parameters[7] > vectorNew[0]*vectorNew[0]*vectorNew[1]*vectorNew[1]*vectorNew[1]) {
+		if(parameters[7] * dist - parameters[7] > x*x*y*y*y) {
 			const double sqrtDist = std::sqrt(dist);
 			const double p = 1.0 - parameters[6] * (static_cast<int>(sqrtDist / parameters[6]) + 1.0) / sqrtDist;
 			vectorNew[0] *= p;