clarify InfluenceVolume API and fields

com.unity.render-pipelines.high-definition/HDRP/Editor/Lighting/Reflection/Volume/SerializedInfluenceVolume.cs

             sphereBlendDistance = root.Find((InfluenceVolume i) => i.sphereBlendDistance);
             sphereBlendNormalDistance = root.Find((InfluenceVolume i) => i.sphereBlendNormalDistance);
 
-            editorAdvancedModeBlendDistancePositive = root.FindPropertyRelative("editorAdvancedModeBlendDistancePositive");
-            editorAdvancedModeBlendDistanceNegative = root.FindPropertyRelative("editorAdvancedModeBlendDistanceNegative");
-            editorSimplifiedModeBlendDistance = root.FindPropertyRelative("editorSimplifiedModeBlendDistance");
-            editorAdvancedModeBlendNormalDistancePositive = root.FindPropertyRelative("editorAdvancedModeBlendNormalDistancePositive");
-            editorAdvancedModeBlendNormalDistanceNegative = root.FindPropertyRelative("editorAdvancedModeBlendNormalDistanceNegative");
-            editorSimplifiedModeBlendNormalDistance = root.FindPropertyRelative("editorSimplifiedModeBlendNormalDistance");
-            editorAdvancedModeEnabled = root.FindPropertyRelative("editorAdvancedModeEnabled");
+            editorAdvancedModeBlendDistancePositive = root.FindPropertyRelative("m_EditorAdvancedModeBlendDistancePositive");
+            editorAdvancedModeBlendDistanceNegative = root.FindPropertyRelative("m_EditorAdvancedModeBlendDistanceNegative");
+            editorSimplifiedModeBlendDistance = root.FindPropertyRelative("m_EditorSimplifiedModeBlendDistance");
+            editorAdvancedModeBlendNormalDistancePositive = root.FindPropertyRelative("m_EditorAdvancedModeBlendNormalDistancePositive");
+            editorAdvancedModeBlendNormalDistanceNegative = root.FindPropertyRelative("m_EditorAdvancedModeBlendNormalDistanceNegative");
+            editorSimplifiedModeBlendNormalDistance = root.FindPropertyRelative("m_EditorSimplifiedModeBlendNormalDistance");
+            editorAdvancedModeEnabled = root.FindPropertyRelative("m_EditorAdvancedModeEnabled");
             //handle data migration from before editor value were saved
             if(editorAdvancedModeBlendDistancePositive.vector3Value == Vector3.zero
                 && editorAdvancedModeBlendDistanceNegative.vector3Value == Vector3.zero

com.unity.render-pipelines.high-definition/HDRP/Lighting/Reflection/Volumes/InfluenceVolume.cs

 using System;
 using UnityEngine.Serialization;
+using UnityEngine.Experimental.Rendering;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
         Vector3 m_SphereBaseOffset;
 
         // Box
-        [SerializeField]
-        Vector3 m_BoxBaseSize = Vector3.one;
+        [SerializeField, FormerlySerializedAs("m_BoxBaseSize")]
+        Vector3 m_BoxSize = Vector3.one;
-        Vector3 m_BoxPositiveFade;
+        Vector3 m_BoxBlendDistancePositive;
-        Vector3 m_BoxNegativeFade;
+        Vector3 m_BoxBlendDistanceNegative;
-        Vector3 m_BoxNormalPositiveFade;
+        Vector3 m_BoxBlendNormalDistancePositive;
-        Vector3 m_BoxNormalNegativeFade;
+        Vector3 m_BoxBlendNormalDistanceNegative;
-        Vector3 m_BoxFacePositiveFade = Vector3.one;
+        Vector3 m_BoxSideFadePositive = Vector3.one;
-        Vector3 m_BoxFaceNegativeFade = Vector3.one;
+        Vector3 m_BoxSideFadeNegative = Vector3.one;
-        [SerializeField] private Vector3 editorAdvancedModeBlendDistancePositive;
-        [SerializeField] private Vector3 editorAdvancedModeBlendDistanceNegative;
-        [SerializeField] private float editorSimplifiedModeBlendDistance;
-        [SerializeField] private Vector3 editorAdvancedModeBlendNormalDistancePositive;
-        [SerializeField] private Vector3 editorAdvancedModeBlendNormalDistanceNegative;
-        [SerializeField] private float editorSimplifiedModeBlendNormalDistance;
-        [SerializeField] private bool editorAdvancedModeEnabled;
+        [SerializeField, FormerlySerializedAs("editorAdvancedModeBlendDistancePositive")]
+        Vector3 m_EditorAdvancedModeBlendDistancePositive;
+        [SerializeField, FormerlySerializedAs("editorAdvancedModeBlendDistanceNegative")]
+        Vector3 m_EditorAdvancedModeBlendDistanceNegative;
+        [SerializeField, FormerlySerializedAs("editorSimplifiedModeBlendDistance")]
+        float m_EditorSimplifiedModeBlendDistance;
+        [SerializeField, FormerlySerializedAs("editorAdvancedModeBlendNormalDistancePositive")]
+        Vector3 m_EditorAdvancedModeBlendNormalDistancePositive;
+        [SerializeField, FormerlySerializedAs("editorAdvancedModeBlendNormalDistanceNegative")]
+        Vector3 m_EditorAdvancedModeBlendNormalDistanceNegative;
+        [SerializeField, FormerlySerializedAs("editorSimplifiedModeBlendNormalDistance")]
+        float m_EditorSimplifiedModeBlendNormalDistance;
+        [SerializeField, FormerlySerializedAs("editorAdvancedModeEnabled")]
+        bool m_EditorAdvancedModeEnabled;
 
         // Sphere
         [SerializeField, FormerlySerializedAs("m_SphereBaseRadius")]
         /// <summary>Offset of this influence volume to the component handling him.</summary>
         public Vector3 offset { get { return m_Offset; } set { m_Offset = value; } }
 
-        public Vector3 boxSize { get { return m_BoxBaseSize; } set { m_BoxBaseSize = value; } }
+        public Vector3 boxSize { get { return m_BoxSize; } set { m_BoxSize = value; } }
-        public Vector3 boxBlendDistancePositive { get { return m_BoxPositiveFade; } set { m_BoxPositiveFade = value; } }
-        public Vector3 boxBlendDistanceNegative { get { return m_BoxNegativeFade; } set { m_BoxNegativeFade = value; } }
-
+        public Vector3 boxBlendDistancePositive { get { return m_BoxBlendDistancePositive; } set { m_BoxBlendDistancePositive = value; } }
+        public Vector3 boxBlendDistanceNegative { get { return m_BoxBlendDistanceNegative; } set { m_BoxBlendDistanceNegative = value; } }
-        public Vector3 boxBlendNormalDistancePositive { get { return m_BoxNormalPositiveFade; } set { m_BoxNormalPositiveFade = value; } }
-        public Vector3 boxBlendNormalDistanceNegative { get { return m_BoxNormalNegativeFade; } set { m_BoxNormalNegativeFade = value; } }
+        public Vector3 boxBlendNormalDistancePositive { get { return m_BoxBlendNormalDistancePositive; } set { m_BoxBlendNormalDistancePositive = value; } }
+        public Vector3 boxBlendNormalDistanceNegative { get { return m_BoxBlendNormalDistanceNegative; } set { m_BoxBlendNormalDistanceNegative = value; } }
-        public Vector3 boxSideFadePositive { get { return m_BoxFacePositiveFade; } set { m_BoxFacePositiveFade = value; } }
-        public Vector3 boxSideFadeNegative { get { return m_BoxFaceNegativeFade; } set { m_BoxFaceNegativeFade = value; } }
+        public Vector3 boxSideFadePositive { get { return m_BoxSideFadePositive; } set { m_BoxSideFadePositive = value; } }
+        public Vector3 boxSideFadeNegative { get { return m_BoxSideFadeNegative; } set { m_BoxSideFadeNegative = value; } }
 
 
         public float sphereRadius { get { return m_SphereRadius; } set { m_SphereRadius = value; } }
-        public BoundingSphere GetBoundingSphereAt(Transform transform)
+        internal BoundingSphere GetBoundingSphereAt(Transform probeTransform)
-                    return new BoundingSphere(transform.TransformPoint(offset), sphereRadius);
+                    return new BoundingSphere(probeTransform.TransformPoint(offset), sphereRadius);
-                    var position = transform.TransformPoint(offset);
+                    var position = probeTransform.TransformPoint(offset);
                     var radius = Mathf.Max(boxSize.x, Mathf.Max(boxSize.y, boxSize.z));
                     return new BoundingSphere(position, radius);
                 }
-        public Bounds GetBoundsAt(Transform transform)
+        internal Bounds GetBoundsAt(Transform probeTransform)
-                    return new Bounds(transform.position, Vector3.one * sphereRadius);
+                    return new Bounds(probeTransform.position, Vector3.one * sphereRadius);
-                    var position = transform.TransformPoint(offset);
-                    // TODO: Return a proper AABB based on influence box volume
+                    var position = probeTransform.TransformPoint(offset);
-        public Vector3 GetWorldPosition(Transform transform)
+        internal Vector3 GetWorldPosition(Transform probeTransform)
-            return transform.TransformPoint(offset);
+            return probeTransform.TransformPoint(offset);
         }
 
         internal void MigrateOffsetSphere()