diff --git a/Code/OysterMath/LinearMath.h b/Code/OysterMath/LinearMath.h
index 0ec46b5c..9ea4bf42 100644
--- a/Code/OysterMath/LinearMath.h
+++ b/Code/OysterMath/LinearMath.h
@@ -752,7 +752,7 @@ namespace LinearAlgebra3D
 	{
 		::LinearAlgebra::Vector4<ScalarType> worldStartNormal( WorldAxisOf(Rotation(startAngularAxis), localStartNormal), (ScalarType)0 );
 		targetMem = ::LinearAlgebra::Vector4<ScalarType>( worldStartNormal.xyz.Cross(worldEndNormal.xyz), (ScalarType)0);
-		targetMem *= (ScalarType)::std::asin( worldStartNormal.Dot(worldEndNormal) );
+		targetMem *= (ScalarType)::std::acos( worldStartNormal.Dot(worldEndNormal) );
 		return targetMem += startAngularAxis;
 	}