use rtc_Center for i3dm's

Dockerfile

@@ -1,6 +1,6 @@
 FROM mcr.microsoft.com/dotnet/sdk:8.0 as build
-WORKDIR /src
 COPY . .
+WORKDIR src
 RUN dotnet build "i3dm.export.csproj" -c Release
 RUN dotnet publish "i3dm.export.csproj" -c Release -o /app
 

README.md

@@ -299,6 +299,8 @@ Press F5 to start debugging.
 
 ## History
 
+2024-08-01: release 2.8.2: fix for I3dm using rtc_center for high precision positions
+
 2024-07-22: release 2.8.1: fix release
 
 2024-07-22: release 2.8.0: to .NET 8.0

src/TileHandler.cs

@@ -37,20 +37,25 @@ public static byte[] GetI3dmTile(List<Instance> instances, bool UseExternalModel
         var modelInstances = instances.Where(s => s.Model.Equals(model)).ToList();
 
         var tags = new List<JArray>();
+        var firstPosition = (Point)modelInstances[0].Position;
+
         CalculateArrays(modelInstances, UseScaleNonUniform, positions, scales, scalesNonUniform, normalUps, normalRights, tags);
-        var i3dm = GetI3dm(model, positions, scales, scalesNonUniform, normalUps, normalRights, tags, UseExternalModel, UseScaleNonUniform);
+
+        var i3dm = GetI3dm(model, positions, firstPosition, scales, scalesNonUniform, normalUps, normalRights, tags, UseExternalModel, UseScaleNonUniform);
         var bytesI3dm = I3dmWriter.Write(i3dm);
         return bytesI3dm;
     }
 
     internal static void CalculateArrays(List<Instance> instances, bool UseScaleNonUniform, List<Vector3> positions, List<float> scales, List<Vector3> scalesNonUniform, List<Vector3> normalUps, List<Vector3> normalRights, List<JArray> tags)
     {
+        var firstPosition = (Point)instances[0].Position;
+
         foreach (var instance in instances)
         {
             var pos = (Point)instance.Position;
             var positionVector3 = new Vector3((float)pos.X, (float)pos.Y, (float)pos.Z.GetValueOrDefault());
 
-            var vec = GetPosition((Point)instance.Position);
+            var vec = GetRelativePosition((Point)instance.Position, firstPosition);
             positions.Add(vec);
 
             if (!UseScaleNonUniform)
@@ -68,7 +73,7 @@ internal static void CalculateArrays(List<Instance> instances, bool UseScaleNonU
         }
     }
 
-    internal static I3dm.Tile.I3dm GetI3dm(object model, List<Vector3> positions, List<float> scales, List<Vector3> scalesNonUniform, List<Vector3> normalUps, List<Vector3> normalRights, List<JArray> tags, bool UseExternalModel = false, bool UseScaleNonUniform = false)
+    internal static I3dm.Tile.I3dm GetI3dm(object model, List<Vector3> positions, Point rtcCenter, List<float> scales, List<Vector3> scalesNonUniform, List<Vector3> normalUps, List<Vector3> normalRights, List<JArray> tags, bool UseExternalModel = false, bool UseScaleNonUniform = false)
     {
         I3dm.Tile.I3dm i3dm = null;
 
@@ -100,7 +105,7 @@ internal static I3dm.Tile.I3dm GetI3dm(object model, List<Vector3> positions, Li
 
         i3dm.NormalUps = normalUps;
         i3dm.NormalRights = normalRights;
-
+        i3dm.RtcCenter = new Vector3((float)rtcCenter.X, (float)rtcCenter.Y, (float)rtcCenter.Z.GetValueOrDefault());
         if (tags[0] != null)
         {
             var properties = TinyJson.GetProperties(tags[0]);
@@ -110,9 +115,13 @@ internal static I3dm.Tile.I3dm GetI3dm(object model, List<Vector3> positions, Li
         return i3dm;
     }
 
-    private static Vector3 GetPosition(Point p)
+    private static Vector3 GetRelativePosition(Point p, Point p_0)
     {
-        var vec = new Vector3((float)(p.X), (float)(p.Y), (float)(p.Z.GetValueOrDefault()));
+        var dx = p.X - p_0.X;
+        var dy = p.Y - p_0.Y;
+        var dz = p.Z.GetValueOrDefault() - p_0.Z.GetValueOrDefault();
+
+        var vec = new Vector3((float)dx, (float)dy, (float)dz);
         return vec;
     }
 }

src/i3dm.export.csproj

@@ -5,9 +5,9 @@
     <TargetFramework>net8.0</TargetFramework>
 	<ToolCommandName>i3dm.export</ToolCommandName>
 	<PackageOutputPath>./nupkg</PackageOutputPath>
-	<Version>2.8.1</Version>
-	<AssemblyVersion>2.8.1</AssemblyVersion>
-	<FileVersion>2.8.1</FileVersion>
+	<Version>2.8.2</Version>
+	<AssemblyVersion>2.8.2</AssemblyVersion>
+	<FileVersion>2.8.2</FileVersion>
 	<PackageProjectUrl>https://github.com/geodan/i3dm.export</PackageProjectUrl>
 	<RepositoryUrl>https://github.com/geodan/i3dm.export</RepositoryUrl>
 	<RepositoryType>git</RepositoryType>

tests/TileHandlerTests.cs

@@ -69,7 +69,7 @@ public void GetTileTest()
         // assert
         Assert.That(tile.Length > 0);
         Assert.That(i3dm.Positions.Count == 1);
-        Assert.That(i3dm.Positions[0] == new Vector3(1, 2, 0));
+        Assert.That(i3dm.Positions[0] == new Vector3(0, 0, 0));
     }
 
     [Test]
@@ -104,13 +104,13 @@ public void GetCompositeTileTest()
         var i3dm0 = I3dmReader.Read(new MemoryStream(cmpt.Tiles.First()));
         Assert.That(i3dm0.Positions.Count == 1);
         Assert.That(i3dm0.GlbUrl.StartsWith("box.glb"));
-        Assert.That(i3dm0.Positions[0] == new Vector3(1, 2, 0));
+        Assert.That(i3dm0.Positions[0] == new Vector3(0, 0, 0));
 
         var i3dm1 = I3dmReader.Read(new MemoryStream(cmpt.Tiles.ToList()[1]));
         Assert.That(i3dm1.Positions.Count == 2);
         Assert.That(i3dm1.GlbUrl.StartsWith("box1.glb"));
-        Assert.That(i3dm1.Positions[0] == new Vector3(3, 4, 0));
-        Assert.That(i3dm1.Positions[1] == new Vector3(5, 6, 0));
+        Assert.That(i3dm1.Positions[0] == new Vector3(0, 0, 0));
+        Assert.That(i3dm1.Positions[1] == new Vector3(2, 2, 0));
     }
 
     [Test]
@@ -182,8 +182,8 @@ public void GetTileWithRtcCenterTest()
         // assert
         Assert.That(tile.Length > 0);
         Assert.That(i3dm.Positions.Count == 2);
-        Assert.That(i3dm.Positions[0] == new Vector3(1, 2, 0));
-        Assert.That(i3dm.Positions[1] == new Vector3(10, 20, 0));
+        Assert.That(i3dm.Positions[0] == new Vector3(0, 0, 0));
+        Assert.That(i3dm.Positions[1] == new Vector3(9, 18, 0));
     }
 
     [Test]