diff --git a/Connectors/Navisworks/Speckle.Connectors.NavisworksShared/Operations/Send/NavisworksRootObjectBuilder.cs b/Connectors/Navisworks/Speckle.Connectors.NavisworksShared/Operations/Send/NavisworksRootObjectBuilder.cs
index af4f25547..39e38df80 100644
--- a/Connectors/Navisworks/Speckle.Connectors.NavisworksShared/Operations/Send/NavisworksRootObjectBuilder.cs
+++ b/Connectors/Navisworks/Speckle.Connectors.NavisworksShared/Operations/Send/NavisworksRootObjectBuilder.cs
@@ -1,4 +1,4 @@
-using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging;
 using Speckle.Connector.Navisworks.HostApp;
 using Speckle.Connector.Navisworks.Services;
 using Speckle.Connectors.Common.Builders;
@@ -27,6 +27,7 @@ public class NavisworksRootObjectBuilder(
   NavisworksMaterialUnpacker materialUnpacker,
   NavisworksColorUnpacker colorUnpacker,
   IElementSelectionService elementSelectionService,
+  IUiUnitsCache uiUnitsCache,
   InstanceStoreManager instanceStoreManager
 ) : IRootObjectBuilder<NAV.ModelItem>
 {
@@ -255,12 +256,14 @@ public class NavisworksRootObjectBuilder(
 
     (string name, string path) = GetElementNameAndPath(convertedBase.applicationId);
 
+    var units = uiUnitsCache.Ensure();
+
     return new NavisworksObject
     {
       name = name,
       displayValue = convertedBase["displayValue"] as List<Base> ?? [],
       properties = convertedBase["properties"] as Dictionary<string, object?> ?? [],
-      units = converterSettings.Current.Derived.SpeckleUnits,
+      units = units.ToString(),
       applicationId = convertedBase.applicationId,
       ["path"] = path
     };
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/PropertySetsExtractor.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/PropertySetsExtractor.cs
index 9b8023f44..485f896e8 100644
--- a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/PropertySetsExtractor.cs
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/PropertySetsExtractor.cs
@@ -1,10 +1,14 @@
-using Speckle.Converter.Navisworks.Settings;
+using Speckle.Converter.Navisworks.Services;
+using Speckle.Converter.Navisworks.Settings;
 using Speckle.Converters.Common;
 using static Speckle.Converter.Navisworks.Helpers.PropertyHelpers;
 
 namespace Speckle.Converter.Navisworks.ToSpeckle;
 
-public class PropertySetsExtractor(IConverterSettingsStore<NavisworksConversionSettings> settingsStore)
+public class PropertySetsExtractor(
+  IConverterSettingsStore<NavisworksConversionSettings> settingsStore,
+  IPropertyConverter propertyConverter
+)
 {
   internal Dictionary<string, object?>? GetPropertySets(NAV.ModelItem modelItem)
   {
@@ -18,9 +22,30 @@ public class PropertySetsExtractor(IConverterSettingsStore<NavisworksConversionS
     return propertyDictionary;
   }
 
+  private static NAV.Units GetModelUnits(NAV.ModelItem modelItem)
+  {
+    NAV.ModelItem? ancestor = modelItem;
+    while (ancestor != null && !ancestor.HasModel)
+    {
+      ancestor = ancestor.Parent;
+    }
+
+    return ancestor != null ? ancestor.Model.Units : NAV.Units.Meters;
+  }
+
+  /// <summary>
+  /// Extracts property sets from a NAV.ModelItem and adds them to a dictionary,
+  /// PropertySets are specific to the host application source appended to Navisworks and therefore
+  /// arbitrary in nature.
+  /// </summary>
+  /// <param name="modelItem">The NAV.ModelItem from which property sets are extracted.</param>
+  /// <returns>A dictionary containing property sets of the modelItem.</returns>
   private Dictionary<string, object?> ExtractPropertySets(NAV.ModelItem modelItem)
   {
     var propertySetDictionary = new Dictionary<string, object?>();
+    var modelUnits = GetModelUnits(modelItem);
+
+    propertyConverter.Reset();
 
     foreach (var propertyCategory in modelItem.PropertyCategories)
     {
@@ -33,23 +58,18 @@ public class PropertySetsExtractor(IConverterSettingsStore<NavisworksConversionS
 
       foreach (var property in propertyCategory.Properties)
       {
-        string sanitizedName = SanitizePropertyName(property.DisplayName);
-        var propertyValue = ConvertPropertyValue(property.Value, settingsStore.Current.Derived.SpeckleUnits);
-
+        var sanitizedName = SanitizePropertyName(property.DisplayName);
+        var propertyValue = propertyConverter.ConvertPropertyValue(property.Value, modelUnits, property.DisplayName);
         if (propertyValue != null)
         {
           propertySet[sanitizedName] = propertyValue;
         }
       }
 
-      if (propertySet.Count <= 0)
+      if (propertySet.Count > 0)
       {
-        continue;
+        propertySetDictionary[SanitizePropertyName(propertyCategory.DisplayName)] = propertySet;
       }
-
-      string categoryName = SanitizePropertyName(propertyCategory.DisplayName);
-
-      propertySetDictionary[categoryName] = propertySet;
     }
 
     return propertySetDictionary;
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/RevitBuiltInCategoryExtractor.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/RevitBuiltInCategoryExtractor.cs
index 5b50dd4e6..9beba6761 100644
--- a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/RevitBuiltInCategoryExtractor.cs
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataExtractors/RevitBuiltInCategoryExtractor.cs
@@ -1,8 +1,10 @@
-using static Speckle.Converter.Navisworks.Helpers.PropertyHelpers;
+using Speckle.Converter.Navisworks.Services;
+using Speckle.InterfaceGenerator;
 
 namespace Speckle.Converter.Navisworks.ToSpeckle;
 
-public sealed class RevitBuiltInCategoryExtractor
+[GenerateAutoInterface]
+public class RevitBuiltInCategoryExtractor(IPropertyConverter converter) : IRevitBuiltInCategoryExtractor
 {
   private const int ANCESTOR_AND_SELF_COUNT = 4; // It seems like this is the maximum depth found needed in practice
   private const string REVIT_CAT_GROUP = "LcRevitData_Element";
@@ -13,28 +15,28 @@ public sealed class RevitBuiltInCategoryExtractor
   /// Attempts to map a Navisworks/Revit display category from the given model item or its ancestors
   /// to a known Revit built-in category constant (e.g., "OST_Walls").
   /// </summary>
-  internal static bool TryGetBuiltInCategory(
-    NAV.ModelItem item,
-    out string mapped,
-    int maxDepth = ANCESTOR_AND_SELF_COUNT
-  )
+  public bool TryGetBuiltInCategory(NAV.ModelItem item, out string mapped, int maxDepth = ANCESTOR_AND_SELF_COUNT)
   {
     mapped = string.Empty;
 
-    // Look up the category value, starting at this item and walking up to maxDepth ancestors
+    // Find the category VariantData up the hierarchy
     var v = FindRevitCategoryInHierarchy(item, maxDepth);
-    if (v == null)
+    if (v is null)
     {
       return false;
     }
 
-    var name = ConvertPropertyValue(v, "")?.ToString();
+    converter.Reset();
+
+    // Convert using per-object model units and current UI units
+    var nameObj = converter.ConvertPropertyValue(v, item.Model.Units, item.DisplayName);
+    var name = nameObj?.ToString();
     if (string.IsNullOrWhiteSpace(name))
     {
       return false;
     }
 
-    name = name?.Trim();
+    name = name!.Trim();
 
     // Map display name to OST_* built-in category constant
     var builtInCategory = DisplayNameToRevitBuiltInCategory(name);
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataHandlers/HierarchicalPropertyHandler.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataHandlers/HierarchicalPropertyHandler.cs
index e882cd5f9..810547887 100644
--- a/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataHandlers/HierarchicalPropertyHandler.cs
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/DataHandlers/HierarchicalPropertyHandler.cs
@@ -11,7 +11,8 @@ public class HierarchicalPropertyHandler(
   PropertySetsExtractor propertySetsExtractor,
   ModelPropertiesExtractor modelPropertiesExtractor,
   ClassPropertiesExtractor classPropertiesExtractor,
-  IConverterSettingsStore<NavisworksConversionSettings> settingsStore
+  IConverterSettingsStore<NavisworksConversionSettings> settingsStore,
+  IRevitBuiltInCategoryExtractor revitCategoryExtractor
 ) : BasePropertyHandler(propertySetsExtractor, modelPropertiesExtractor)
 {
   private static string PseudoClassPropertiesKey => "_pseudoClassProperties";
@@ -22,7 +23,7 @@ public class HierarchicalPropertyHandler(
     var propertyDict = classPropertiesExtractor.GetClassProperties(modelItem) ?? [];
 
     // Interop-lite mapping for Revit built-in categories
-    if (_mapRevit && RevitBuiltInCategoryExtractor.TryGetBuiltInCategory(modelItem, out var builtInCategory))
+    if (_mapRevit && revitCategoryExtractor.TryGetBuiltInCategory(modelItem, out var builtInCategory))
     {
       PropertyHelpers.AddPropertyIfNotNullOrEmpty(
         propertyDict,
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Helpers/PropertyHelpers.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Helpers/PropertyHelpers.cs
index 225ae249f..b6fc07ae4 100644
--- a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Helpers/PropertyHelpers.cs
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Helpers/PropertyHelpers.cs
@@ -1,4 +1,4 @@
-using System.Globalization;
+using System.Globalization;
 using System.Text.RegularExpressions;
 using Speckle.Objects.Geometry;
 
@@ -8,6 +8,9 @@ public static class PropertyHelpers
 {
   private static readonly HashSet<string> s_excludedCategories = ["Geometry", "Metadata"];
 
+  /// <summary>
+  /// Adds a property to an object (either a Base object or a Dictionary) if the value is not null or empty.
+  /// </summary>
   private static readonly Dictionary<NAV.VariantDataType, Func<NAV.VariantData, string, dynamic?>> s_typeHandlers =
     new()
     {
@@ -92,3 +95,27 @@ public static class PropertyHelpers
   internal static bool ShouldSkipCategory(NAV.PropertyCategory propertyCategory) =>
     s_excludedCategories.Contains(propertyCategory.DisplayName);
 }
+
+internal static class UnitLabels
+{
+  internal static string Linear(NAV.Units u) =>
+    u switch
+    {
+      NAV.Units.Kilometers => "Kilometers",
+      NAV.Units.Meters => "Metres",
+      NAV.Units.Centimeters => "Centimeters",
+      NAV.Units.Millimeters => "Millimeters",
+      NAV.Units.Micrometers => "Micrometers",
+      NAV.Units.Miles => "Miles",
+      NAV.Units.Yards => "Yards",
+      NAV.Units.Feet => "Feet",
+      NAV.Units.Inches => "Inches",
+      NAV.Units.Mils => "Mils",
+      NAV.Units.Microinches => "Microinches",
+      _ => "Metres"
+    };
+
+  internal static string Area(NAV.Units u) => $"Square {Linear(u).ToLower()}";
+
+  public static string Volume(NAV.Units u) => $"Cubic {Linear(u).ToLower()}";
+}
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/PropertyConversion.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/PropertyConversion.cs
new file mode 100644
index 000000000..36497010d
--- /dev/null
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/PropertyConversion.cs
@@ -0,0 +1,91 @@
+using System.Globalization;
+using Speckle.Converter.Navisworks.Helpers;
+using Speckle.InterfaceGenerator;
+
+namespace Speckle.Converter.Navisworks.Services;
+
+[GenerateAutoInterface]
+public class PropertyConverter(IUiUnitsCache uiUnitsCache) : IPropertyConverter
+{
+  public void Reset() => uiUnitsCache.Reset();
+
+  public object? ConvertPropertyValue(NAV.VariantData? value, NAV.Units modelUnits, string propDisplayName) =>
+    value == null
+      ? null
+      : _handlers.TryGetValue(value.DataType, out var f)
+        ? f(value, (modelUnits, propDisplayName))
+        : value.DataType is NAV.VariantDataType.None or NAV.VariantDataType.Point2D
+          ? null
+          : value.ToString();
+
+  private readonly Dictionary<
+    NAV.VariantDataType,
+    Func<NAV.VariantData, (NAV.Units model, string name), object?>
+  > _handlers =
+    new()
+    {
+      { NAV.VariantDataType.Boolean, (v, _) => v.ToBoolean() },
+      { NAV.VariantDataType.DisplayString, (v, _) => v.ToDisplayString() },
+      { NAV.VariantDataType.IdentifierString, (v, _) => v.ToIdentifierString() },
+      { NAV.VariantDataType.Int32, (v, _) => v.ToInt32() },
+      { NAV.VariantDataType.Double, (v, _) => v.ToDouble() },
+      // Angle as dictionary with units
+      { NAV.VariantDataType.DoubleAngle, (v, t) => NumObj(t.name, v.ToDoubleAngle(), "Degrees") },
+      // Length → dictionary in UI units
+      {
+        NAV.VariantDataType.DoubleLength,
+        (v, t) =>
+        {
+          var uiUnits = uiUnitsCache.Ensure();
+
+          var k = NAV.UnitConversion.ScaleFactor(t.model, uiUnits);
+          return NumObj(t.name, v.ToDoubleLength() * k, UnitLabels.Linear(uiUnits));
+        }
+      },
+      // Area → dictionary in UI units^2
+      {
+        NAV.VariantDataType.DoubleArea,
+        (v, t) =>
+        {
+          var uiUnits = uiUnitsCache.Ensure();
+          var k = NAV.UnitConversion.ScaleFactor(t.model, uiUnits);
+          k *= k;
+          return NumObj(t.name, v.ToDoubleArea() * k, UnitLabels.Area(uiUnits));
+        }
+      },
+      // Volume → dictionary in UI units^3
+      {
+        NAV.VariantDataType.DoubleVolume,
+        (v, t) =>
+        {
+          var uiUnits = uiUnitsCache.Ensure();
+          var k = NAV.UnitConversion.ScaleFactor(t.model, uiUnits);
+          k = k * k * k;
+          return NumObj(t.name, v.ToDoubleVolume() * k, UnitLabels.Volume(uiUnits));
+        }
+      },
+      { NAV.VariantDataType.DateTime, (v, _) => v.ToDateTime().ToString(CultureInfo.InvariantCulture) },
+      { NAV.VariantDataType.NamedConstant, (v, _) => v.ToNamedConstant().DisplayName },
+      { NAV.VariantDataType.None, (_, _) => null },
+      { NAV.VariantDataType.Point2D, (_, _) => null },
+      {
+        NAV.VariantDataType.Point3D,
+        (v, t) =>
+        {
+          var uiUnits = uiUnitsCache.Ensure();
+          var k = NAV.UnitConversion.ScaleFactor(t.model, uiUnits);
+          var p = v.ToPoint3D();
+
+          return new Speckle.Objects.Geometry.Point(p.X * k, p.Y * k, p.Z * k, UnitLabels.Linear(uiUnits));
+        }
+      }
+    };
+
+  private static Dictionary<string, object> NumObj(string name, double value, string units) =>
+    new()
+    {
+      ["name"] = name,
+      ["value"] = value,
+      ["units"] = units
+    };
+}
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/UIUnits.cs b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/UIUnits.cs
new file mode 100644
index 000000000..26183a697
--- /dev/null
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Services/UIUnits.cs
@@ -0,0 +1,71 @@
+using Autodesk.Navisworks.Api.Interop;
+using Speckle.InterfaceGenerator;
+using static Autodesk.Navisworks.Api.Interop.LcUOption;
+
+namespace Speckle.Converter.Navisworks.Services;
+
+[GenerateAutoInterface]
+public class UiUnitsCache : IUiUnitsCache
+{
+  private NAV.Units? _ui;
+
+  public NAV.Units Ensure()
+  {
+    if (_ui.HasValue)
+    {
+      return _ui.Value;
+    }
+
+    UiUnitsUtil.TryGetUiLinearUnits(out var ui);
+    _ui = ui;
+    return _ui.Value;
+  }
+
+  public void Reset() => _ui = null;
+}
+
+public static class UiUnitsUtil
+{
+  // disp_units: 0=linear_format
+  public static bool TryGetUiLinearUnits(out NAV.Units uiUnits)
+  {
+    using var opt = new LcUOptionLock();
+    var root = GetRoot(opt);
+    var disp = root.GetSubOptions("interface").GetSubOptions("disp_units");
+
+    int code = -1;
+
+    using var v = new NAV.VariantData();
+    disp.GetValue(0, v);
+    var s = v.ToString();
+    var colon = s.LastIndexOf(':');
+    var open = s.IndexOf('(', colon + 1);
+    if (colon >= 0 && open > colon && !int.TryParse(s.Substring(colon + 1, open - colon - 1), out code))
+    {
+      code = -1;
+    }
+
+    uiUnits = code switch
+    {
+      0 => NAV.Units.Kilometers,
+      1 => NAV.Units.Meters,
+      2 => NAV.Units.Centimeters,
+      3 => NAV.Units.Millimeters,
+      4 => NAV.Units.Micrometers,
+      5 => NAV.Units.Miles,
+      6 => NAV.Units.Miles,
+      7 => NAV.Units.Yards,
+      8 => NAV.Units.Yards,
+      9 => NAV.Units.Feet,
+      10 => NAV.Units.Feet,
+      11 => NAV.Units.Feet,
+      12 => NAV.Units.Inches,
+      13 => NAV.Units.Inches,
+      14 => NAV.Units.Mils,
+      15 => NAV.Units.Microinches,
+      _ => NAV.Units.Meters
+    };
+
+    return code >= 0;
+  }
+}
diff --git a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Speckle.Converters.NavisworksShared.projitems b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Speckle.Converters.NavisworksShared.projitems
index 24e198b16..2523f527d 100644
--- a/Converters/Navisworks/Speckle.Converters.NavisworksShared/Speckle.Converters.NavisworksShared.projitems
+++ b/Converters/Navisworks/Speckle.Converters.NavisworksShared/Speckle.Converters.NavisworksShared.projitems
@@ -30,6 +30,8 @@
     <Compile Include="$(MSBuildThisFileDirectory)GlobalUsing.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)Helpers\GeometryHelpers.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)PathConstants.cs"/>
+    <Compile Include="$(MSBuildThisFileDirectory)Services\PropertyConversion.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Services\UIUnits.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)Services\SharedGeometryStores.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)Services\InstanceStoreManager.cs"/>
     <Compile Include="$(MSBuildThisFileDirectory)ToSpeckle\Raw\GeometryToSpeckleConverter.cs"/>