diff --git a/common/mathlib.cc b/common/mathlib.cc
index ec843201..80047be2 100644
--- a/common/mathlib.cc
+++ b/common/mathlib.cc
@@ -775,10 +775,7 @@ float SignedDegreesBetweenUnitVectors(const vec3_t start, const vec3_t end, cons
 {
     const float cosangle = qmax(-1.0, qmin(1.0, DotProduct(start, end)));
     const float unsigned_degrees = acos(cosangle) * (360.0 / (2.0 * Q_PI));
-    
-    if (unsigned_degrees < ANGLEEPSILON)
-        return 0;
-    
+
     // get a normal for the rotation plane using the right-hand rule
     vec3_t rotationNormal;
     CrossProduct(start, end, rotationNormal);
diff --git a/include/common/mathlib.hh b/include/common/mathlib.hh
index 02ea75ee..8e4256fb 100644
--- a/include/common/mathlib.hh
+++ b/include/common/mathlib.hh
@@ -56,7 +56,6 @@ typedef struct {
 
 extern const vec3_t vec3_origin;
 
-#define ANGLEEPSILON            0.000001
 #define ZERO_TRI_AREA_EPSILON 0.05f
 #define POINT_EQUAL_EPSILON 0.05f
 
diff --git a/light/test_light.cc b/light/test_light.cc
index 551873ab..a3bf7184 100644
--- a/light/test_light.cc
+++ b/light/test_light.cc
@@ -419,6 +419,7 @@ TEST(mathlib, SignedDegreesBetweenUnitVectors) {
     
     EXPECT_FLOAT_EQ(-90, SignedDegreesBetweenUnitVectors(right, fwd, up));
     EXPECT_FLOAT_EQ(90, SignedDegreesBetweenUnitVectors(fwd, right, up));
+    EXPECT_FLOAT_EQ(0, SignedDegreesBetweenUnitVectors(right, right, up));
 }
 
 static const float MANGLE_EPSILON = 0.1f;