diff --git a/math/MathUtil.cs b/math/MathUtil.cs
index 6c5723a6..6f00b591 100644
--- a/math/MathUtil.cs
+++ b/math/MathUtil.cs
@@ -371,12 +371,12 @@ public static float SmoothRise0To1(float fX, float yshift, float xZero, float sp
         }
 
         public static float WyvillRise01(float fX) {
-            float d = 1 - fX * fX;
-            return (d >= 0) ? 1 - (d * d * d) : 0;
+            float d = MathUtil.Clamp(1.0f - fX*fX, 0.0f, 1.0f);
+            return 1 - (d * d * d);
         }
         public static double WyvillRise01(double fX) {
-            double d = 1 - fX * fX;
-            return (d >= 0) ? 1 - (d * d * d) : 0;
+            double d = MathUtil.Clamp(1.0 - fX*fX, 0.0, 1.0);
+            return 1 - (d * d * d);
         }
 
         public static float WyvillFalloff01(float fX) {