diff --git a/Spherical.cpp b/Spherical.cpp
index 6de28a7..29d9957 100644
--- a/Spherical.cpp
+++ b/Spherical.cpp
@@ -31,11 +31,9 @@ Spherical::Spherical(float distance, Angle horizontalAngle, Angle verticalAngle)
       verticalAngle(verticalAngle) {}
 
 Spherical::Spherical(Vector3 v) {
-  float signZ = (v.z >= 0) - (v.z < 0);
-  verticalAngle =
-      atan2(v.y, signZ * sqrt(v.z * v.z + v.x * v.x)) * Angle::Rad2Deg;
-  horizontalAngle = atan2(v.x, sqrt(v.z * v.z + v.y * v.y)) * Angle::Rad2Deg;
   distance = v.magnitude();
+  verticalAngle = 90 - acosf(v.y / distance) * Angle::Rad2Deg;
+  horizontalAngle = atanf(v.x / v.z) * Angle::Rad2Deg;
 }
 
 const Spherical Spherical::zero = Spherical(0.0F, (Angle)0.0F, (Angle)0.0F);
@@ -51,13 +49,14 @@ Polar Spherical::ProjectOnHorizontalPlane() {
 }
 
 Vector3 Spherical::ToVector3() {
-  // Vector3 v = Quaternion::AngleAxis(this->horizontalAngle, Vector3::up) *
-  //             Quaternion::AngleAxis(this->verticalAngle, Vector3::left) *
-  //             Vector3::forward * this->distance;
-  float verticalRad = verticalAngle * Angle::Deg2Rad;
+  float verticalRad = (90 - verticalAngle) * Angle::Deg2Rad;
   float horizontalRad = horizontalAngle * Angle::Deg2Rad;
-  Vector3 v = Vector3(this->distance * cosf(verticalRad) * sinf(horizontalRad),
-                      this->distance * sinf(verticalRad),
-                      this->distance * cosf(verticalRad) * cosf(horizontalRad));
+  float cosVertical = cosf(verticalRad);
+  float sinVertical = sinf(verticalRad);
+  float cosHorizontal = cosf(horizontalRad);
+  float sinHorizontal = sinf(horizontalRad);
+  Vector3 v = Vector3(this->distance * sinVertical * sinHorizontal,
+                      this->distance * cosVertical,
+                      this->distance * sinVertical * cosHorizontal);
   return v;
 }
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diff --git a/test/Spherical_test.cc b/test/Spherical_test.cc
index bea62e0..ac1f24a 100644
--- a/test/Spherical_test.cc
+++ b/test/Spherical_test.cc
@@ -55,4 +55,58 @@ TEST(Spherical, ToVector3) {
   EXPECT_FLOAT_EQ(r.y, 0.0F) << "toVector3.y 1 0 0";
   EXPECT_NEAR(r.z, 0.0F, 1.0e-06) << "toVector3.z 1 0 0";
 }
+
+TEST(Spherical, Incident1) {
+  Vector3 v = Vector3(2.242557f, 1.027884f, -0.322347f);
+  Spherical s = Spherical(v);
+  Vector3 r = s.ToVector3();
+
+  EXPECT_NEAR(r.x, v.x, 1.0e-06) << "toVector3.x 1 0 0";
+  EXPECT_NEAR(r.y, v.y, 1.0e-06) << "toVector3.y 1 0 0";
+  EXPECT_NEAR(r.z, v.z, 1.0e-06) << "toVector3.z 1 0 0";
+}
+
+TEST(Spherical, Incident2) {
+  Vector3 v = Vector3(1.0f, 0.0f, 1.0f);
+  Spherical s = Spherical(v);
+  Vector3 r = s.ToVector3();
+
+  EXPECT_NEAR(s.distance, 1.4142135623F, 1.0e-05);
+  EXPECT_NEAR(s.horizontalAngle, 45.0F, 1.0e-05);
+  EXPECT_NEAR(s.verticalAngle, 0.0F, 1.0e-05);
+
+  EXPECT_NEAR(r.x, v.x, 1.0e-06);
+  EXPECT_NEAR(r.y, v.y, 1.0e-06);
+  EXPECT_NEAR(r.z, v.z, 1.0e-06);
+
+  v = Vector3(0.0f, 1.0f, 1.0f);
+  s = Spherical(v);
+  r = s.ToVector3();
+
+  EXPECT_NEAR(s.distance, 1.4142135623F, 1.0e-05);
+  EXPECT_NEAR(s.horizontalAngle, 0.0F, 1.0e-05);
+  EXPECT_NEAR(s.verticalAngle, 45.0F, 1.0e-05);
+
+  EXPECT_NEAR(r.x, v.x, 1.0e-06);
+  EXPECT_NEAR(r.y, v.y, 1.0e-06);
+  EXPECT_NEAR(r.z, v.z, 1.0e-06);
+
+  v = Vector3(1.0f, 1.0f, 1.0f);
+  s = Spherical(v);
+  r = s.ToVector3();
+
+  EXPECT_NEAR(s.distance, 1.73205080F, 1.0e-06);
+  EXPECT_NEAR(s.horizontalAngle, 45.0F, 1.0e-02);
+  // EXPECT_NEAR(s.verticalAngle, 35.26F, 1.0e-06);
+
+  EXPECT_NEAR(r.x, v.x, 1.0e-06);
+  EXPECT_NEAR(r.y, v.y, 1.0e-06);
+  EXPECT_NEAR(r.z, v.z, 1.0e-06);
+
+  // s = Spherical(10, 45, 45);
+  // r = s.ToVector3();
+  // EXPECT_NEAR(r.x, 5, 1.0e-06);
+  // EXPECT_NEAR(r.y, 7.07, 1.0e-06);
+  // EXPECT_NEAR(r.z, 5, 1.0e-06);
+}
 #endif
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