diff --git a/Curve/SplineCurve3D.cs b/Curve/SplineCurve3D.cs
index 38b94db..49cf457 100644
--- a/Curve/SplineCurve3D.cs
+++ b/Curve/SplineCurve3D.cs
@@ -8,12 +8,12 @@ namespace MoonTools.Curve
     /// </summary>
     public struct SplineCurve3D
     {
-        public ImmutableArray<ICurve3D> Curves { get; }
-        public ImmutableArray<float> Times { get; }
+        private ICurve3D[] Curves { get; }
+        private float[] Times { get; }
         public float TotalTime { get; }
         public bool Loop { get; }
 
-        public SplineCurve3D(ImmutableArray<ICurve3D> curves, ImmutableArray<float> times, bool loop = false)
+        public SplineCurve3D(ICurve3D[] curves, float[] times, bool loop = false)
         {
             TotalTime = 0;
 
@@ -51,7 +51,7 @@ namespace MoonTools.Curve
                 }
 
                 index++;
-                startTime = Times[i];
+                startTime = incrementalTime;
             }
 
             return Curves[index].Point(t - startTime, 0, Times[index]);