Read the surface entity family as modeler geometry

src/ACadSharp.Tests/IO/DXF/DxfSurfaceTests.cs

@@ -0,0 +1,128 @@
+using ACadSharp.Entities;
+using ACadSharp.IO;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Xunit;
+
+namespace ACadSharp.Tests.IO.DXF;
+
+public class DxfSurfaceTests
+{
+	[Fact]
+	public void ReadGenericSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("SURFACE", "AcDbSurface"));
+
+		Surface surface = Assert.IsType<Surface>(doc.Entities.Single());
+		Assert.Equal(6, surface.UIsolines);
+		Assert.Equal(7, surface.VIsolines);
+		Assert.Equal(SatHeader + "\n" + SatBody, surface.GetAcisText());
+	}
+
+	[Fact]
+	public void ReadPlaneSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("PLANESURFACE", "AcDbSurface", "AcDbPlaneSurface"));
+
+		PlaneSurface surface = Assert.IsType<PlaneSurface>(doc.Entities.Single());
+		Assert.Equal(6, surface.UIsolines);
+		Assert.Equal(7, surface.VIsolines);
+		Assert.Equal(SatHeader + "\n" + SatBody, surface.GetAcisText());
+	}
+
+	[Fact]
+	public void ReadExtrudedSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("EXTRUDEDSURFACE", "AcDbSurface", "AcDbExtrudedSurface"));
+
+		ExtrudedSurface surface = Assert.IsType<ExtrudedSurface>(doc.Entities.Single());
+		Assert.Equal(6, surface.UIsolines);
+		Assert.Equal(7, surface.VIsolines);
+		Assert.Equal(SatHeader + "\n" + SatBody, surface.GetAcisText());
+	}
+
+	[Fact]
+	public void ReadLoftedSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("LOFTEDSURFACE", "AcDbSurface", "AcDbLoftedSurface"));
+
+		Assert.IsType<LoftedSurface>(doc.Entities.Single());
+	}
+
+	[Fact]
+	public void ReadRevolvedSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("REVOLVEDSURFACE", "AcDbSurface", "AcDbRevolvedSurface"));
+
+		Assert.IsType<RevolvedSurface>(doc.Entities.Single());
+	}
+
+	[Fact]
+	public void ReadSweptSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("SWEPTSURFACE", "AcDbSurface", "AcDbSweptSurface"));
+
+		Assert.IsType<SweptSurface>(doc.Entities.Single());
+	}
+
+	[Fact]
+	public void ReadNurbSurface()
+	{
+		CadDocument doc = readDxf(surfaceDxf("NURBSURFACE", "AcDbSurface", "AcDbNurbSurface"));
+
+		Assert.IsType<NurbSurface>(doc.Entities.Single());
+	}
+
+	private const string SatHeader = "400 0 1 0";
+
+	private const string SatBody = "body $-1 $1 $-1 $-1 #";
+
+	//A minimal entities section with one surface entity: the modeler geometry
+	//codes (70, 1, 3) carry the SAT text, the AcDbSurface codes 71 and 72 the
+	//isoline counts, followed by the empty subclass of the derived surface.
+	private static string surfaceDxf(string name, params string[] subclasses)
+	{
+		StringBuilder dxf = new StringBuilder();
+		void add(string code, string value)
+		{
+			dxf.Append(code).Append('\n').Append(value).Append('\n');
+		}
+
+		add("0", "SECTION");
+		add("2", "ENTITIES");
+		add("0", name);
+		add("5", "A1");
+		add("100", "AcDbEntity");
+		add("8", "0");
+		add("100", "AcDbModelerGeometry");
+		add("70", "1");
+		add("1", SatHeader);
+		add("1", SatBody);
+
+		foreach (string subclass in subclasses)
+		{
+			add("100", subclass);
+
+			if (subclass == "AcDbSurface")
+			{
+				add("71", "6");
+				add("72", "7");
+			}
+		}
+
+		add("0", "ENDSEC");
+		add("0", "EOF");
+
+		return dxf.ToString();
+	}
+
+	private static CadDocument readDxf(string dxf)
+	{
+		using (MemoryStream stream = new MemoryStream(Encoding.ASCII.GetBytes(dxf)))
+		using (DxfReader reader = new DxfReader(stream))
+		{
+			return reader.Read();
+		}
+	}
+}

src/ACadSharp.Tests/IO/WriterSingleObjectTests.cs

@@ -93,6 +93,7 @@ static WriterSingleObjectTests()
 		Data.Add(new(nameof(SingleCaseGenerator.XData)));
 		Data.Add(new(nameof(SingleCaseGenerator.XRef)));
 		Data.Add(new(nameof(SingleCaseGenerator.SPlineCreation)));
+		Data.Add(new(nameof(SingleCaseGenerator.SurfaceEntities)));
 		Data.Add(new(nameof(SingleCaseGenerator.TextAlignment)));
 		Data.Add(new(nameof(SingleCaseGenerator.InvalidEntities)));
 		Data.Add(new(nameof(SingleCaseGenerator.CreateXRecords)));
@@ -2676,6 +2677,27 @@ public void SPlineCreation()
 			};
 		}
 
+		public void SurfaceEntities()
+		{
+			Line line = new Line(XYZ.Zero, new XYZ(10, 10, 0));
+			this.Document.Entities.Add(line);
+
+			//Surfaces are not written yet, the writers skip them
+			this.Document.Entities.Add(new Surface());
+			this.Document.Entities.Add(new ExtrudedSurface());
+			this.Document.Entities.Add(new LoftedSurface());
+			this.Document.Entities.Add(new NurbSurface());
+			this.Document.Entities.Add(new PlaneSurface());
+			this.Document.Entities.Add(new RevolvedSurface());
+			this.Document.Entities.Add(new SweptSurface());
+
+			this.AssertRoundtrip = (doc) =>
+			{
+				Assert.NotNull(doc.GetCadObject<Line>(line.Handle));
+				Assert.Empty(doc.Entities.OfType<Surface>());
+			};
+		}
+
 		public void TextAlignment()
 		{
 			XYZ insert = new XYZ(0, 0, 0);

src/ACadSharp/DxfFileToken.cs

@@ -68,6 +68,8 @@ public static class DxfFileToken
 
 	public const string EntityEllipse = "ELLIPSE";
 
+	public const string EntityExtrudedSurface = "EXTRUDEDSURFACE";
+
 	public const string EntityHatch = "HATCH";
 
 	public const string EntityHelix = "HELIX";
@@ -82,6 +84,8 @@ public static class DxfFileToken
 
 	public const string EntityLine = "LINE";
 
+	public const string EntityLoftedSurface = "LOFTEDSURFACE";
+
 	public const string EntityLwPolyline = "LWPOLYLINE";
 
 	public const string EntityMesh = "MESH";
@@ -92,12 +96,16 @@ public static class DxfFileToken
 
 	public const string EntityMultiLeader = "MULTILEADER";
 
+	public const string EntityNurbSurface = "NURBSURFACE";
+
 	public const string EntityOle2Frame = "OLE2FRAME";
 
 	public const string EntityOleFrame = "OLEFRAME";
 
 	public const string EntityPdfUnderlay = "PDFUNDERLAY";
 
+	public const string EntityPlaneSurface = "PLANESURFACE";
+
 	public const string EntityPoint = "POINT";
 
 	public const string EntityPolyFaceMesh = "PFACE";
@@ -110,6 +118,8 @@ public static class DxfFileToken
 
 	public const string EntityRegion = "REGION";
 
+	public const string EntityRevolvedSurface = "REVOLVEDSURFACE";
+
 	public const string EntitySection = "SECTION";
 
 	public const string EntitySeqend = "SEQEND";
@@ -124,6 +134,8 @@ public static class DxfFileToken
 
 	public const string EntitySurface = "SURFACE";
 
+	public const string EntitySweptSurface = "SWEPTSURFACE";
+
 	public const string EntityTable = "ACAD_TABLE";
 
 	public const string EntityText = "TEXT";

src/ACadSharp/DxfSubclassMarker.cs

@@ -144,6 +144,8 @@ public static class DxfSubclassMarker
 
 	public const string EvalGraphExpr = "AcDbEvalExpr";
 
+	public const string ExtrudedSurface = "AcDbExtrudedSurface";
+
 	public const string Face3d = "AcDbFace";
 
 	public const string Field = "AcDbField";
@@ -182,6 +184,8 @@ public static class DxfSubclassMarker
 
 	public const string LinkedTableData = "AcDbLinkedTableData";
 
+	public const string LoftedSurface = "AcDbLoftedSurface";
+
 	public const string LwPolyline = "AcDbPolyline";
 
 	public const string Material = "AcDbMaterial";
@@ -206,6 +210,8 @@ public static class DxfSubclassMarker
 
 	public const string MultiLeaderObjectContextData = "AcDbMLeaderObjectContextData";
 
+	public const string NurbSurface = "AcDbNurbSurface";
+
 	public const string ObjectContextData = "AcDbObjectContextData";
 
 	public const string Ole2Frame = "AcDbOle2Frame";
@@ -220,6 +226,8 @@ public static class DxfSubclassMarker
 
 	public const string PdfReference = "AcDbPdfReference";
 
+	public const string PlaneSurface = "AcDbPlaneSurface";
+
 	public const string PlotSettings = "AcDbPlotSettings";
 
 	public const string Point = "AcDbPoint";
@@ -258,6 +266,8 @@ public static class DxfSubclassMarker
 
 	public const string Ray = "AcDbRay";
 
+	public const string RevolvedSurface = "AcDbRevolvedSurface";
+
 	public const string Scale = "AcDbScale";
 
 	public const string Shape = "AcDbShape";
@@ -272,6 +282,10 @@ public static class DxfSubclassMarker
 
 	public const string Spline = "AcDbSpline";
 
+	public const string Surface = "AcDbSurface";
+
+	public const string SweptSurface = "AcDbSweptSurface";
+
 	public const string Table = "AcDbSymbolTable";
 
 	public const string TableContent = "AcDbTableContent";

src/ACadSharp/Entities/ExtrudedSurface.cs

@@ -0,0 +1,37 @@
+using ACadSharp.Attributes;
+using ACadSharp.Classes;
+
+namespace ACadSharp.Entities;
+
+/// <summary>
+/// Represents an <see cref="ExtrudedSurface"/> entity.
+/// </summary>
+/// <remarks>
+/// Object name <see cref="DxfFileToken.EntityExtrudedSurface"/> <br/>
+/// Dxf class name <see cref="DxfSubclassMarker.ExtrudedSurface"/>
+/// </remarks>
+[DxfName(DxfFileToken.EntityExtrudedSurface)]
+[DxfSubClass(DxfSubclassMarker.ExtrudedSurface)]
+public class ExtrudedSurface : Surface
+{
+	/// <inheritdoc/>
+	public override string ObjectName => DxfFileToken.EntityExtrudedSurface;
+
+	/// <inheritdoc/>
+	public override string SubclassMarker => DxfSubclassMarker.ExtrudedSurface;
+
+	/// <inheritdoc/>
+	public override DxfClass GetDxfClass()
+	{
+		return new DxfClass
+		{
+			CppClassName = DxfSubclassMarker.ExtrudedSurface,
+			DwgVersion = (ACadVersion)26,
+			DxfName = DxfFileToken.EntityExtrudedSurface,
+			ItemClassId = 498,
+			MaintenanceVersion = 0,
+			ProxyFlags = ProxyFlags.None,
+			WasZombie = false,
+		};
+	}
+}

src/ACadSharp/Entities/LoftedSurface.cs

@@ -0,0 +1,37 @@
+using ACadSharp.Attributes;
+using ACadSharp.Classes;
+
+namespace ACadSharp.Entities;
+
+/// <summary>
+/// Represents a <see cref="LoftedSurface"/> entity.
+/// </summary>
+/// <remarks>
+/// Object name <see cref="DxfFileToken.EntityLoftedSurface"/> <br/>
+/// Dxf class name <see cref="DxfSubclassMarker.LoftedSurface"/>
+/// </remarks>
+[DxfName(DxfFileToken.EntityLoftedSurface)]
+[DxfSubClass(DxfSubclassMarker.LoftedSurface)]
+public class LoftedSurface : Surface
+{
+	/// <inheritdoc/>
+	public override string ObjectName => DxfFileToken.EntityLoftedSurface;
+
+	/// <inheritdoc/>
+	public override string SubclassMarker => DxfSubclassMarker.LoftedSurface;
+
+	/// <inheritdoc/>
+	public override DxfClass GetDxfClass()
+	{
+		return new DxfClass
+		{
+			CppClassName = DxfSubclassMarker.LoftedSurface,
+			DwgVersion = (ACadVersion)26,
+			DxfName = DxfFileToken.EntityLoftedSurface,
+			ItemClassId = 498,
+			MaintenanceVersion = 0,
+			ProxyFlags = ProxyFlags.None,
+			WasZombie = false,
+		};
+	}
+}

src/ACadSharp/Entities/NurbSurface.cs

@@ -0,0 +1,37 @@
+using ACadSharp.Attributes;
+using ACadSharp.Classes;
+
+namespace ACadSharp.Entities;
+
+/// <summary>
+/// Represents a <see cref="NurbSurface"/> entity.
+/// </summary>
+/// <remarks>
+/// Object name <see cref="DxfFileToken.EntityNurbSurface"/> <br/>
+/// Dxf class name <see cref="DxfSubclassMarker.NurbSurface"/>
+/// </remarks>
+[DxfName(DxfFileToken.EntityNurbSurface)]
+[DxfSubClass(DxfSubclassMarker.NurbSurface)]
+public class NurbSurface : Surface
+{
+	/// <inheritdoc/>
+	public override string ObjectName => DxfFileToken.EntityNurbSurface;
+
+	/// <inheritdoc/>
+	public override string SubclassMarker => DxfSubclassMarker.NurbSurface;
+
+	/// <inheritdoc/>
+	public override DxfClass GetDxfClass()
+	{
+		return new DxfClass
+		{
+			CppClassName = DxfSubclassMarker.NurbSurface,
+			DwgVersion = (ACadVersion)26,
+			DxfName = DxfFileToken.EntityNurbSurface,
+			ItemClassId = 498,
+			MaintenanceVersion = 0,
+			ProxyFlags = (ProxyFlags)4095,
+			WasZombie = false,
+		};
+	}
+}