diff --git a/Code/OysterPhysics3D/OysterCollision3D.cpp b/Code/OysterPhysics3D/OysterCollision3D.cpp
index cc68d536..41e11875 100644
--- a/Code/OysterPhysics3D/OysterCollision3D.cpp
+++ b/Code/OysterPhysics3D/OysterCollision3D.cpp
@@ -1064,38 +1064,42 @@ namespace Oyster { namespace Collision3D { namespace Utility
 
 	Float TimeOfContact( const Sphere &protoStart, const Sphere &protoEnd, const Point &deuter )
 	{ // Bisection with 5 levels of detail
-		Float t = 0.5f;
+		Float t = 0.5f,
+			  d = 0.25f;
 		Sphere s;
 		for( int i = 0; i < 5; ++i )
 		{
 			Nlerp( protoStart, protoEnd, t, s );
 			if( Intersect(s, deuter) )
 			{
-				t *= 0.5f;
+				t -= d;
 			}
 			else
 			{
-				t *= 1.5f;
+				t += d;
 			}
+			d *= 0.5f;
 		}
 		return t;
 	}
 
 	Float TimeOfContact( const Box &protoStart, const Box &protoEnd, const Point &deuter )
 	{ // Bisection with 5 levels of detail
-		Float t = 0.5f;
+		Float t = 0.5f,
+			  d = 0.25f;
 		Box b;
 		for( int i = 0; i < 5; ++i )
 		{
 			Nlerp( protoStart, protoEnd, t, b );
 			if( Intersect(b, deuter) )
 			{
-				t *= 0.5f;
+				t -= d;
 			}
 			else
 			{
-				t *= 1.5f;
+				t += d;
 			}
+			d *= 0.5f;
 		}
 		return t;
 	}