diff --git a/csharp/Facebook.Yoga/YogaNode.Create.cs b/csharp/Facebook.Yoga/YogaNode.Create.cs
index d40d9732..ee0726b5 100644
--- a/csharp/Facebook.Yoga/YogaNode.Create.cs
+++ b/csharp/Facebook.Yoga/YogaNode.Create.cs
@@ -31,12 +31,12 @@ namespace Facebook.Yoga
             Spacing margin = null,
             Spacing padding = null,
             Border border = null,
-            YogaValue? Width = null,
-            YogaValue? Height = null,
-            YogaValue? MaxWidth = null,
-            YogaValue? MaxHeight = null,
-            YogaValue? MinWidth = null,
-            YogaValue? MinHeight = null)
+            YogaValue? width = null,
+            YogaValue? height = null,
+            YogaValue? maxWidth = null,
+            YogaValue? maxHeight = null,
+            YogaValue? minWidth = null,
+            YogaValue? minHeight = null)
         {
             YogaNode node = new YogaNode();
 
@@ -197,34 +197,34 @@ namespace Facebook.Yoga
                 }
             }
 
-            if (Width.HasValue)
+            if (width.HasValue)
             {
-                node.Width = Width.Value;
+                node.Width = width.Value;
             }
 
-            if (Height.HasValue)
+            if (height.HasValue)
             {
-                node.Height = Height.Value;
+                node.Height = height.Value;
             }
 
-            if (MinWidth.HasValue)
+            if (minWidth.HasValue)
             {
-                node.MinWidth = MinWidth.Value;
+                node.MinWidth = minWidth.Value;
             }
 
-            if (MinHeight.HasValue)
+            if (minHeight.HasValue)
             {
-                node.MinHeight = MinHeight.Value;
+                node.MinHeight = minHeight.Value;
             }
 
-            if (MaxWidth.HasValue)
+            if (maxWidth.HasValue)
             {
-                node.MaxWidth = MaxWidth.Value;
+                node.MaxWidth = maxWidth.Value;
             }
 
-            if (MaxHeight.HasValue)
+            if (maxHeight.HasValue)
             {
-                node.MaxHeight = MaxHeight.Value;
+                node.MaxHeight = maxHeight.Value;
             }
 
             return node;
diff --git a/csharp/Facebook.Yoga/YogaValue.cs b/csharp/Facebook.Yoga/YogaValue.cs
index 15d60e65..7e1acba8 100644
--- a/csharp/Facebook.Yoga/YogaValue.cs
+++ b/csharp/Facebook.Yoga/YogaValue.cs
@@ -16,7 +16,7 @@ namespace Facebook.Yoga
     {
         private float Value;
         private YogaUnit Unit;
-        private byte isDefined;
+        private byte isDefined; /* use byte to keep struct blitable */
 
         public bool IsDefined => isDefined != 0;
 
@@ -25,7 +25,7 @@ namespace Facebook.Yoga
             return new YogaValue
             {
                 Value = value,
-                isDefined = 1,
+                isDefined = YogaConstants.IsUndefined(value) ? (byte)0 : (byte)1,
                 Unit = YogaUnit.Pixel
             };
         }
@@ -49,12 +49,22 @@ namespace Facebook.Yoga
             }
         }
 
+        public static YogaValue Undefined()
+        {
+            return new YogaValue
+            {
+                Value = YogaConstants.Undefined,
+                isDefined = 0,
+                Unit = YogaUnit.Pixel
+            };
+        }
+
         public static YogaValue Percent(float value)
         {
             return new YogaValue
             {
                 Value = value,
-                isDefined = 1,
+                isDefined = YogaConstants.IsUndefined(value) ? (byte)0 : (byte)1,,
                 Unit = YogaUnit.Percent
             };
         }
diff --git a/tests/YGAspectRatioTest.cpp b/tests/YGAspectRatioTest.cpp
index 22846c9b..7dd4ccc0 100644
--- a/tests/YGAspectRatioTest.cpp
+++ b/tests/YGAspectRatioTest.cpp
@@ -24,11 +24,11 @@ static YGSize _measure(YGNodeRef node,
 TEST(YogaTest, aspect_ratio_cross_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetWidth(root_child0, 50);
+  YGNodeStyleSetWidth(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -45,11 +45,11 @@ TEST(YogaTest, aspect_ratio_cross_defined) {
 TEST(YogaTest, aspect_ratio_main_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -65,11 +65,11 @@ TEST(YogaTest, aspect_ratio_main_defined) {
 
 TEST(YogaTest, aspect_ratio_both_dimensions_defined) {
   const YGNodeRef root = YGNodeNew();
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -85,8 +85,8 @@ TEST(YogaTest, aspect_ratio_both_dimensions_defined) {
 
 TEST(YogaTest, aspect_ratio_align_stretch) {
   const YGNodeRef root = YGNodeNew();
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetAspectRatio(root_child0, 1);
@@ -105,11 +105,11 @@ TEST(YogaTest, aspect_ratio_align_stretch) {
 TEST(YogaTest, aspect_ratio_flex_grow) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
   YGNodeStyleSetFlexGrow(root_child0, 1);
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
@@ -127,11 +127,11 @@ TEST(YogaTest, aspect_ratio_flex_grow) {
 TEST(YogaTest, aspect_ratio_flex_shrink) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 150);
+  YGNodeStyleSetHeight(root_child0, YGPx(150));
   YGNodeStyleSetFlexShrink(root_child0, 1);
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
@@ -149,11 +149,11 @@ TEST(YogaTest, aspect_ratio_flex_shrink) {
 TEST(YogaTest, aspect_ratio_basis) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetFlexBasis(root_child0, 50);
+  YGNodeStyleSetFlexBasis(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -169,14 +169,14 @@ TEST(YogaTest, aspect_ratio_basis) {
 
 TEST(YogaTest, aspect_ratio_absolute_layout_width_defined) {
   const YGNodeRef root = YGNodeNew();
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetPositionType(root_child0, YGPositionTypeAbsolute);
-  YGNodeStyleSetPosition(root_child0, YGEdgeLeft, 0);
-  YGNodeStyleSetPosition(root_child0, YGEdgeTop, 0);
-  YGNodeStyleSetWidth(root_child0, 50);
+  YGNodeStyleSetPosition(root_child0, YGEdgeLeft, YGPx(0));
+  YGNodeStyleSetPosition(root_child0, YGEdgeTop, YGPx(0));
+  YGNodeStyleSetWidth(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -192,14 +192,14 @@ TEST(YogaTest, aspect_ratio_absolute_layout_width_defined) {
 
 TEST(YogaTest, aspect_ratio_absolute_layout_height_defined) {
   const YGNodeRef root = YGNodeNew();
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetPositionType(root_child0, YGPositionTypeAbsolute);
-  YGNodeStyleSetPosition(root_child0, YGEdgeLeft, 0);
-  YGNodeStyleSetPosition(root_child0, YGEdgeTop, 0);
-  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeStyleSetPosition(root_child0, YGEdgeLeft, YGPx(0));
+  YGNodeStyleSetPosition(root_child0, YGEdgeTop, YGPx(0));
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -216,12 +216,12 @@ TEST(YogaTest, aspect_ratio_absolute_layout_height_defined) {
 TEST(YogaTest, aspect_ratio_with_max_cross_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 50);
-  YGNodeStyleSetMaxWidth(root_child0, 40);
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
+  YGNodeStyleSetMaxWidth(root_child0, YGPx(40));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -238,12 +238,12 @@ TEST(YogaTest, aspect_ratio_with_max_cross_defined) {
 TEST(YogaTest, aspect_ratio_with_max_main_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetWidth(root_child0, 50);
-  YGNodeStyleSetMaxHeight(root_child0, 40);
+  YGNodeStyleSetWidth(root_child0, YGPx(50));
+  YGNodeStyleSetMaxHeight(root_child0, YGPx(40));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -260,12 +260,12 @@ TEST(YogaTest, aspect_ratio_with_max_main_defined) {
 TEST(YogaTest, aspect_ratio_with_min_cross_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 30);
-  YGNodeStyleSetMinWidth(root_child0, 40);
+  YGNodeStyleSetHeight(root_child0, YGPx(30));
+  YGNodeStyleSetMinWidth(root_child0, YGPx(40));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -282,12 +282,12 @@ TEST(YogaTest, aspect_ratio_with_min_cross_defined) {
 TEST(YogaTest, aspect_ratio_with_min_main_defined) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetWidth(root_child0, 30);
-  YGNodeStyleSetMinHeight(root_child0, 40);
+  YGNodeStyleSetWidth(root_child0, YGPx(30));
+  YGNodeStyleSetMinHeight(root_child0, YGPx(40));
   YGNodeStyleSetAspectRatio(root_child0, 1);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -304,11 +304,11 @@ TEST(YogaTest, aspect_ratio_with_min_main_defined) {
 TEST(YogaTest, aspect_ratio_double_cross) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 50);
+  YGNodeStyleSetHeight(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 2);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -325,11 +325,11 @@ TEST(YogaTest, aspect_ratio_double_cross) {
 TEST(YogaTest, aspect_ratio_half_cross) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetHeight(root_child0, 100);
+  YGNodeStyleSetHeight(root_child0, YGPx(100));
   YGNodeStyleSetAspectRatio(root_child0, 0.5);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -346,11 +346,11 @@ TEST(YogaTest, aspect_ratio_half_cross) {
 TEST(YogaTest, aspect_ratio_double_main) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetWidth(root_child0, 50);
+  YGNodeStyleSetWidth(root_child0, YGPx(50));
   YGNodeStyleSetAspectRatio(root_child0, 2);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -367,11 +367,11 @@ TEST(YogaTest, aspect_ratio_double_main) {
 TEST(YogaTest, aspect_ratio_half_main) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
-  YGNodeStyleSetWidth(root_child0, 100);
+  YGNodeStyleSetWidth(root_child0, YGPx(100));
   YGNodeStyleSetAspectRatio(root_child0, 0.5);
   YGNodeInsertChild(root, root_child0, 0);
 
@@ -388,8 +388,8 @@ TEST(YogaTest, aspect_ratio_half_main) {
 TEST(YogaTest, aspect_ratio_with_measure_func) {
   const YGNodeRef root = YGNodeNew();
   YGNodeStyleSetAlignItems(root, YGAlignFlexStart);
-  YGNodeStyleSetWidth(root, 100);
-  YGNodeStyleSetHeight(root, 100);
+  YGNodeStyleSetWidth(root, YGPx(100));
+  YGNodeStyleSetHeight(root, YGPx(100));
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeSetMeasureFunc(root_child0, _measure);
diff --git a/tests/YGMeasureModeTest.cpp b/tests/YGMeasureModeTest.cpp
index ad766043..9bbbbfa9 100644
--- a/tests/YGMeasureModeTest.cpp
+++ b/tests/YGMeasureModeTest.cpp
@@ -243,7 +243,7 @@ TEST(YogaTest, flex_child_with_flex_basis) {
 
   const YGNodeRef root_child0 = YGNodeNew();
   YGNodeStyleSetFlexGrow(root_child0, 1);
-  YGNodeStyleSetFlexBasis(root_child0, 0);
+  YGNodeStyleSetFlexBasis(root_child0, YGPx(0));
   YGNodeSetContext(root_child0, &constraintList);
   YGNodeSetMeasureFunc(root_child0, _measure);
   YGNodeInsertChild(root, root_child0, 0);