Changed the way heightmaps scale and bias are displayed in the GUI. It's now H = (h - center) * amplitude.

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Editor/BaseLitUI.cs

             public static GUIContent normalMapText = new GUIContent("Normal Map", "Normal Map (DXT5) - Need to implement BC5");
  
             public static GUIContent heightMapText = new GUIContent("Height Map (R)", "Height Map");
+            public static GUIContent heightMapAmplitudeText = new GUIContent("Height Map Amplitude", "Height Map amplitude in world units.");
+            public static GUIContent heightMapCenterText = new GUIContent("Height Map Center", "Center of the heightmap in the texture (between 0 and 1)");
 
             public static GUIContent tangentMapText = new GUIContent("Tangent Map", "Tangent Map (BC5) - DXT5 for test");
             public static GUIContent anisotropyText = new GUIContent("Anisotropy", "Anisotropy scale factor");

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Editor/LitUI.cs

 
             m_MaterialEditor.TexturePropertySingleLine(Styles.normalMapText, normalMap, normalScale);
 
-            m_MaterialEditor.TexturePropertySingleLine(Styles.heightMapText, heightMap, heightScale, heightBias);
+            m_MaterialEditor.TexturePropertySingleLine(Styles.heightMapText, heightMap);
+            if(!heightMap.hasMixedValue && heightMap.textureValue != null)
+            {
+                // Be careful, the scale and bias here is different from the one shader properties
+                // In the shader values are in world units and the formula is finalHeight = height * scale + bias
+                // In the GUI it's (height - center) * amplitude
+                EditorGUI.indentLevel++;
+                float amplitude = heightScale.floatValue;
+                float center = -heightBias.floatValue / amplitude;
+                // Scale = Amplitude so no need for special handling
+                m_MaterialEditor.ShaderProperty(heightScale, Styles.heightMapAmplitudeText);
+
+                EditorGUI.showMixedValue = heightScale.hasMixedValue;
+                EditorGUI.BeginChangeCheck();
+                float newCenter = EditorGUILayout.FloatField(Styles.heightMapCenterText, center);
+                if(EditorGUI.EndChangeCheck())
+                {
+                    heightBias.floatValue = -newCenter * amplitude;
+                }
+                EditorGUI.showMixedValue = false;
+                EditorGUI.indentLevel--;
+            }
 
             m_MaterialEditor.TexturePropertySingleLine(Styles.tangentMapText, tangentMap);
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.shader

         _NormalMap("NormalMap", 2D) = "bump" {}
         _NormalScale("_NormalScale", Range(0.0, 2.0)) = 1
 
+        // Be careful, the scale and bias here is different from the one shown in the GUI
+        // Here both value are in world units and the formula is finalHeight = height * scale + bias
+        // In the GUI it's (height - center) * amplitude
-        _HeightBias("Height Bias", Float) = 0
+        _HeightBias("Height Bias", Float) = -0.005
 
         _TangentMap("TangentMap", 2D) = "bump" {}
         _Anisotropy("Anisotropy", Range(0.0, 1.0)) = 0