Solid self intersection with better triangulation to eliminate false positives

CityDoctorParent/CityDoctorModel/pom.xml

@@ -58,6 +58,14 @@
 			<groupId>org.locationtech.proj4j</groupId>
 			<artifactId>proj4j</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.locationtech.jts</groupId>
+			<artifactId>jts-core</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>io.github.earcut4j</groupId>
+			<artifactId>earcut4j</artifactId>
+		</dependency>
 	</dependencies>
 	<build>
 		<resources>

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/math/MovedPolygon.java

@@ -39,6 +39,25 @@ public class MovedPolygon {
 	private MovedRing exteriorRing;
 	private List<MovedRing> innerRings;
 
+	/**
+	 * Moves the polygon by the first exterior vertex. The center of the polygon
+	 * will not me the origin, the polygon will just be near the origin. This can
+	 * eliviate numeric issues in large calculations.
+	 * 
+	 * @param p the polygon that is moved to the center.
+	 * @return the moved polygon.
+	 */
+	public static MovedPolygon ofPolygon(Polygon p) {
+		Vector3d movedBy = p.getExteriorRing().getVertices().get(0);
+		MovedPolygon indPoly = new MovedPolygon();
+		indPoly.original = p;
+		indPoly.exteriorRing = MovedRing.ofRing(p.getExteriorRing(), movedBy);
+		for (LinearRing inner : p.getInnerRings()) {
+			indPoly.addInnerRing(MovedRing.ofRing(inner, movedBy));
+		}
+		return indPoly;
+	}
+
 	public static MovedPolygon ofPolygon(Polygon p, Vector3d movedBy) {
 		MovedPolygon indPoly = new MovedPolygon();
 		indPoly.original = p;

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/math/Polygon2d.java

@@ -41,6 +41,11 @@ public class Polygon2d {
 		return projectTo2D(poly, axis);
 	}
 	
+	public static Polygon2d withProjection(MovedPolygon poly) {
+		ProjectionAxis axis = ProjectionAxis.of(poly.getOriginal());
+		return projectTo2D(poly, axis);
+	}
+
 	public static Polygon2d withProjection(MovedPolygon poly, ProjectionAxis projectionAxis) {
 		return projectTo2D(poly, projectionAxis);
 	}

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/math/Vector3d.java

@@ -22,6 +22,8 @@ import java.io.Serial;
 import java.io.Serializable;
 import java.util.Arrays;
 
+import org.locationtech.jts.geom.Coordinate;
+
 /**
  * A three dimensional vector
  * 
@@ -45,6 +47,17 @@ public class Vector3d implements Serializable {
 		this(0d, 0d, 0d);
 	}
 	
+	/**
+	 * Convert JTS Coordinate class to Vector3d.
+	 * @param coord JTS Coordinate
+	 */
+	public Vector3d(Coordinate coord) {
+		coords = new double[3];
+		coords[0] = coord.getX();
+		coords[1] = coord.getY();
+		coords[2] = coord.getZ();
+	}
+
 	public Vector3d(double x, double y, double z) {
 		coords = new double[3];
 		coords[0] = x;

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/tesselation/EarcutTesselator.java

+package de.hft.stuttgart.citydoctor2.tesselation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
+import de.hft.stuttgart.citydoctor2.math.Polygon2d;
+import de.hft.stuttgart.citydoctor2.math.Ring2d;
+import de.hft.stuttgart.citydoctor2.math.Triangle3d;
+import de.hft.stuttgart.citydoctor2.math.Vector2d;
+import earcut4j.Earcut;
+
+/**
+ * Tesselator to create triangles out of polygons. Uses earcut4j implementation.
+ * 
+ * @author Matthias Betz
+ *
+ */
+public class EarcutTesselator {
+
+	public static TesselatedPolygon tesselatePolygon(Polygon p) {
+		// sum number of vertices, don't use duplicate last point
+		// assume polygons are closed
+		int nrOfVertices = p.getExteriorRing().getVertices().size() - 1;
+		int[] holeStart = null;
+		if (!p.getInnerRings().isEmpty()) {
+			holeStart = new int[p.getInnerRings().size()];
+			List<LinearRing> innerRings = p.getInnerRings();
+			for (int i = 0; i < innerRings.size(); i++) {
+				LinearRing r = innerRings.get(i);
+				holeStart[i] = nrOfVertices;
+				nrOfVertices += r.getVertices().size() - 1;
+			}
+		}
+		// collect vertices
+		// project polygon to 2D space as library is buggy for more than 2 dimensions
+		Polygon2d projectedPolygon = Polygon2d.withProjection(p);
+		
+		double[] vertices = new double[nrOfVertices * 2];
+		List<Vertex> vertexObjects = new ArrayList<>();
+		addVerticesToList(p.getExteriorRing(), vertexObjects);
+		for (LinearRing innerRing : p.getInnerRings()) {
+			addVerticesToList(innerRing, vertexObjects);
+		}
+		
+		int start = addRingToArray(projectedPolygon.getExterior(), vertices, 0);
+		for (Ring2d innerRing : projectedPolygon.getInteriorRings()) {
+			start = addRingToArray(innerRing, vertices, start);
+		}
+		
+		// triangulation
+		List<Integer> indices = Earcut.earcut(vertices, holeStart, 2);
+		List<Triangle3d> triangles = new ArrayList<>();
+		if (indices.size() % 3 != 0) {
+			throw new IllegalStateException();
+		}
+		for (int i = 0; i < indices.size(); i = i + 3) {
+			Triangle3d t = new Triangle3d(vertexObjects.get(indices.get(i + 0)),
+					vertexObjects.get(indices.get(i + 1)),
+					vertexObjects.get(indices.get(i + 2)));
+			triangles.add(t);
+		}
+		return new TesselatedPolygon(triangles, p);
+	}
+
+	private static void addVerticesToList(LinearRing ring, List<Vertex> vertexObjects) {
+		List<Vertex> vertices = ring.getVertices();
+		for (int i = 0; i < vertices.size() - 1; i++) {
+			Vertex v = vertices.get(i);
+			vertexObjects.add(v);
+		}
+	}
+
+	private static int addRingToArray(Ring2d ring, double[] vertices, int start) {
+		List<Vector2d> ringVertices = ring.getVertices();
+		for (int i = 0; i < ringVertices.size() - 1; i++) {
+			Vector2d v = ringVertices.get(i);
+			vertices[start++] = v.getX();
+			vertices[start++] = v.getY();
+		}
+		return start;
+	}
+	
+	private EarcutTesselator() {
+	}
+
+}

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/tesselation/JoglTesselator.java

@@ -33,7 +33,7 @@ import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
 import de.hft.stuttgart.citydoctor2.math.Vector3d;
 
 /**
- * Tesselator to create triangles out of polygons.
+ * Tesselator to create triangles out of polygons. Uses JOGL implementation.
  * 
  * @author Matthias Betz
  *
@@ -102,6 +102,10 @@ public class JoglTesselator {
 	}
 
 	public static TesselatedPolygon tesselatePolygon(Polygon p) {
+		return tesselatePolygon(p, true);
+	}
+	
+	public static TesselatedPolygon tesselatePolygon(Polygon p, boolean discardDegeneratedTriangles) {
 		ArrayList<Vector3d> vertices = new ArrayList<>();
 		Vector3d normal = p.calculateNormalNormalized();
 		synchronized (tess) {
@@ -121,7 +125,7 @@ public class JoglTesselator {
 			GLU.gluTessEndPolygon(tess);
 			ArrayList<Integer> indices = new ArrayList<>();
 			for (Primitive primitive : primitives) {
-				primitive.fillListWithIndices(indices);
+				primitive.fillListWithIndices(indices, discardDegeneratedTriangles);
 			}
 			primitives.clear();
 			return new TesselatedPolygon(vertices, indices, p);
@@ -137,7 +141,7 @@ public class JoglTesselator {
 		GLU.gluTessEndContour(tess);
 	}
 
-	public static TesselatedRing tesselateRing(LinearRing r) {
+	public static TesselatedRing tesselateRing(LinearRing r, boolean discardDegeneratedTriangles) {
 		ArrayList<Vector3d> vertices = new ArrayList<>();
 		Vector3d normal = r.calculateNormal();
 		synchronized (tess) {
@@ -147,13 +151,17 @@ public class JoglTesselator {
 			GLU.gluTessEndPolygon(tess);
 			ArrayList<Integer> indices = new ArrayList<>();
 			for (Primitive primitive : primitives) {
-				primitive.fillListWithIndices(indices);
+				primitive.fillListWithIndices(indices, discardDegeneratedTriangles);
 			}
 			primitives.clear();
 			return new TesselatedRing(vertices, indices, r);
 		}
 	}
 	
+	public static TesselatedRing tesselateRing(LinearRing r) {
+		return tesselateRing(r, true);
+	}
+
 	private JoglTesselator() {
 		// only static useage
 	}

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/tesselation/Primitive.java

@@ -49,30 +49,34 @@ public class Primitive {
 		this.type = type;
 	}
 
-	public void fillListWithIndices(List<Integer> indices) {
+	public void fillListWithIndices(List<Integer> indices, boolean discardDegeneratedTriangles) {
 		switch (type) {
 		case GL.GL_TRIANGLES:
 			for (int i = 0; i < pIndices.size(); i += 3) {
-				addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 1), pIndices.get(i + 2), indices);
+				addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 1), pIndices.get(i + 2), indices,
+						discardDegeneratedTriangles);
 			}
 			break;
 		case GL.GL_TRIANGLE_STRIP:
 			for (int i = 0; i < pIndices.size() - 2; i++) {
 				if (i % 2 == 0) {
-					addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 1), pIndices.get(i + 2), indices);
+					addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 1), pIndices.get(i + 2), indices,
+							discardDegeneratedTriangles);
 				} else {
-					addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 2), pIndices.get(i + 1), indices);
+					addToListIfAreaNonNull(pIndices.get(i), pIndices.get(i + 2), pIndices.get(i + 1), indices,
+							discardDegeneratedTriangles);
 				}
 			}
 			break;
 		case GL.GL_TRIANGLE_FAN:
 			Integer first = pIndices.get(0);
 			for (int i = 0; i < pIndices.size() - 2; i++) {
-				addToListIfAreaNonNull(first, pIndices.get(i + 1), pIndices.get(i + 2), indices);
+				addToListIfAreaNonNull(first, pIndices.get(i + 1), pIndices.get(i + 2), indices,
+						discardDegeneratedTriangles);
 			}
 			break;
 		default:
-			throw new IllegalStateException("unknown type found: " + type);
+			throw new IllegalStateException("unknown triangle type found: " + type);
 		}
 	}
 
@@ -80,17 +84,18 @@ public class Primitive {
 		pIndices.add(i);
 	}
 
-	private void addToListIfAreaNonNull(Integer i1, Integer i2, Integer i3, List<Integer> indices) {
+	private void addToListIfAreaNonNull(Integer i1, Integer i2, Integer i3, List<Integer> indices,
+			boolean discardDegeneratedTriangles) {
 		Vector3d v1 = vertices.get(i1);
 		Vector3d v2 = vertices.get(i2);
 		Vector3d v3 = vertices.get(i3);
-		double area = Math.abs(calculateAreaOfTriangle(v1, v2, v3));
-		if (area > AREA_EPSILON) {
+		if (discardDegeneratedTriangles && Math.abs(calculateAreaOfTriangle(v1, v2, v3)) <= AREA_EPSILON) {
+			// switch to discard degenerated triangles is enabled and triangle has nearly no area
+			logger.trace("Tesselator created degenerated triangle, ignoring");
+		} else {
 			indices.add(i1);
 			indices.add(i2);
 			indices.add(i3);
-		} else {
-			logger.trace("Tesselator created degenerated triangle, ignoring");
 		}
 	}
 

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/utils/PolygonIntersection.java

@@ -25,6 +25,7 @@ import java.util.List;
 import de.hft.stuttgart.citydoctor2.datastructure.ConcretePolygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
 import de.hft.stuttgart.citydoctor2.math.Segment3d;
+import de.hft.stuttgart.citydoctor2.math.Triangle3d;
 
 /**
  * Result of a polygon polygon intersection.
@@ -38,7 +39,7 @@ public class PolygonIntersection implements Serializable {
 	private static final long serialVersionUID = -6301963226688351725L;
 
 	public enum IntersectionType {
-		NONE, LINE, POLYGON
+		NONE, LINE, POLYGON, TRIANGLES
 	}
 
 	private final IntersectionType type;
@@ -48,10 +49,30 @@ public class PolygonIntersection implements Serializable {
 	private Polygon p1;
 	private Polygon p2;
 	
+	private Triangle3d t1;
+	private Triangle3d t2;
+
 	public static PolygonIntersection none() {
 		return new PolygonIntersection(IntersectionType.NONE);
 	}
 	
+	
+	public static PolygonIntersection triangles(Triangle3d t1, Triangle3d t2) {
+		PolygonIntersection poly = new PolygonIntersection(IntersectionType.TRIANGLES);
+		poly.p1 = t1.getPartOf().getOriginal();
+		poly.p2 = t2.getPartOf().getOriginal();
+		poly.t1 = t1;
+		poly.t2 = t2;
+		return poly;
+	}
+	
+	public static PolygonIntersection any(Polygon p1, Polygon p2) {
+		PolygonIntersection poly = new PolygonIntersection(IntersectionType.POLYGON);
+		poly.p1 = p1;
+		poly.p2 = p2;
+		return poly;
+	}
+
 	public static PolygonIntersection lines(List<Segment3d> lines, Polygon p1, Polygon p2) {
 		PolygonIntersection poly = new PolygonIntersection(IntersectionType.LINE);
 		poly.lines = lines;
@@ -76,6 +97,14 @@ public class PolygonIntersection implements Serializable {
 		return p2;
 	}
 	
+	public Triangle3d getT1() {
+		return t1;
+	}
+	
+	public Triangle3d getT2() {
+		return t2;
+	}
+
 	private PolygonIntersection(IntersectionType type) {
 		this.type = type;
 	}

CityDoctorParent/CityDoctorModel/src/main/resources/CityDoctorLocalization.properties

@@ -120,3 +120,12 @@ MainWindow.memoryLabel=Memory:
 CheckDialog.checksReenabledAlert=Some checks have been reenabled so that other wanted checks can be executed\nSee the log for more information.
 MainWindow.availableLabel=Available:
 OpenFileDialog.lowMemoryLabel=Low Memory Consumption Mode
+ErrorItemVisitor.intersection=Intersection
+ErrorItemVisitor.component=Component
+ErrorItemVisitor.nameOfAttribute=Name of attribute
+ErrorItemVisitor.childId=Child id
+ErrorItemVisitor.distance=Distance
+ErrorItemVisitor.pointTouchesEdge=Point touches edge
+ErrorItemVisitor.degeneratedRing=Degenerated ring
+ErrorItemVisitor.deviation=Deviation
+ErrorItemVisitor.triangles=Triangles
\ No newline at end of file

CityDoctorParent/CityDoctorModel/src/main/resources/CityDoctorLocalization_de.properties

@@ -118,3 +118,12 @@ MainWindow.memoryLabel=Speicher:
 CheckDialog.checksReenabledAlert=Manche Pr\u00fcfungen wurden reaktiviert damit andere gewollte Pr\u00fcfungen durchgef\u00fchrt werden k\u00f6nnen\nMehr Details sind im Log geschrieben
 MainWindow.availableLabel=Verf\u00fcgbar:
 OpenFileDialog.lowMemoryLabel=Reduzierter Speicherverbrauchsmodus
+ErrorItemVisitor.intersection=Verschneidung
+ErrorItemVisitor.component=Komponente
+ErrorItemVisitor.nameOfAttribute=Name des Attributs
+ErrorItemVisitor.childId=Kind ID
+ErrorItemVisitor.distance=Distanz
+ErrorItemVisitor.pointTouchesEdge=Punkt ber\u00fchrt Kante
+ErrorItemVisitor.degeneratedRing=Degenerierter Ring
+ErrorItemVisitor.deviation=Abweichung
+ErrorItemVisitor.triangles=Dreiecke
\ No newline at end of file

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/geometry/SolidSelfIntCheck.java

@@ -27,19 +27,16 @@ import de.hft.stuttgart.citydoctor2.check.Check;
 import de.hft.stuttgart.citydoctor2.check.CheckError;
 import de.hft.stuttgart.citydoctor2.check.CheckId;
 import de.hft.stuttgart.citydoctor2.check.CheckResult;
-import de.hft.stuttgart.citydoctor2.check.RequirementType;
 import de.hft.stuttgart.citydoctor2.check.GeometrySelfIntersection;
 import de.hft.stuttgart.citydoctor2.check.Requirement;
+import de.hft.stuttgart.citydoctor2.check.RequirementType;
 import de.hft.stuttgart.citydoctor2.check.ResultStatus;
 import de.hft.stuttgart.citydoctor2.check.error.SolidSelfIntError;
 import de.hft.stuttgart.citydoctor2.checks.util.CollectionUtils;
 import de.hft.stuttgart.citydoctor2.checks.util.SelfIntersectionUtil;
-import de.hft.stuttgart.citydoctor2.datastructure.ConcretePolygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Geometry;
 import de.hft.stuttgart.citydoctor2.datastructure.GeometryType;
-import de.hft.stuttgart.citydoctor2.math.Segment3d;
 import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection;
-import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection.IntersectionType;
 
 /**
  * Check for self intersecting solids
@@ -78,7 +75,8 @@ public class SolidSelfIntCheck extends Check {
 			return;
 		}
 		CheckResult cr;
-		List<PolygonIntersection> intersections = SelfIntersectionUtil.doesSolidSelfIntersect2(g);
+		List<PolygonIntersection> intersections = SelfIntersectionUtil.calculateSolidSelfIntersection(g);
+//		List<PolygonIntersection> intersections = SelfIntersectionUtil.doesSolidSelfIntersect2(g);
 		if (intersections.isEmpty()) {
 			cr = new CheckResult(this, ResultStatus.OK, null);
 		} else {

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/util/SelfIntersectionUtil.java

@@ -62,6 +62,7 @@ import de.hft.stuttgart.citydoctor2.math.Segment3d;
 import de.hft.stuttgart.citydoctor2.math.Triangle3d;
 import de.hft.stuttgart.citydoctor2.math.Vector2d;
 import de.hft.stuttgart.citydoctor2.math.Vector3d;
+import de.hft.stuttgart.citydoctor2.tesselation.EarcutTesselator;
 import de.hft.stuttgart.citydoctor2.tesselation.JoglTesselator;
 import de.hft.stuttgart.citydoctor2.tesselation.TesselatedPolygon;
 import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection;
@@ -75,7 +76,6 @@ import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection.IntersectionType;
  */
 public class SelfIntersectionUtil {
 
-
 	private static final Logger logger = LogManager.getLogger(SelfIntersectionUtil.class);
 
 	private static final GeometryFactory factory = new GeometryFactory(new PrecisionModel(PrecisionModel.FLOATING));
@@ -84,6 +84,25 @@ public class SelfIntersectionUtil {
 
 	}
 
+	public static List<PolygonIntersection> calculateSolidSelfIntersection(Geometry g) {
+		List<TesselatedPolygon> tesselatedPolygons = new ArrayList<>();
+		for (Polygon p : g.getPolygons()) {
+			tesselatedPolygons.add(EarcutTesselator.tesselatePolygon(p));
+		}
+		List<PolygonIntersection> intersections = new ArrayList<>();
+		for (int i = 0; i < tesselatedPolygons.size() - 1; i++) {
+			TesselatedPolygon p1 = tesselatedPolygons.get(i);
+			for (int j = i + 1; j < tesselatedPolygons.size(); j++) {
+				TesselatedPolygon p2 = tesselatedPolygons.get(j);
+				GeometrySelfIntersection intersection = doPolygonsIntersect(p1, p2);
+				if (intersection != null) {
+					intersections.add(PolygonIntersection.triangles(intersection.t1(), intersection.t2()));
+				}
+			}
+		}
+		return intersections;
+	}
+
 	public static GeometrySelfIntersection doesSolidSelfIntersect(Geometry g) {
 		return selfIntersectionJava(g);
 	}
@@ -114,14 +133,15 @@ public class SelfIntersectionUtil {
 		return intersections;
 	}
 
-	private static void performEdgeSelfIntersection(List<PolygonIntersection> intersections, Map<Polygon, EdgePolygon> edgePolyMap,
-			Polygon p1, Polygon p2) {
+	private static void performEdgeSelfIntersection(List<PolygonIntersection> intersections,
+			Map<Polygon, EdgePolygon> edgePolyMap, Polygon p1, Polygon p2) {
 		EdgePolygon edgeP1 = edgePolyMap.get(p1);
 		EdgePolygon edgeP2 = edgePolyMap.get(p2);
-		List<PolygonPolygonIntersection> results = IntersectPlanarPolygons.intersectPolygons(edgeP1, edgeP2, 0.000001, 0.001);
+		List<PolygonPolygonIntersection> results = IntersectPlanarPolygons.intersectPolygons(edgeP1, edgeP2, 0.000001,
+				0.001);
 		if (!results.isEmpty()) {
 			// at least one intersection happened
-			for (PolygonPolygonIntersection result: results) {
+			for (PolygonPolygonIntersection result : results) {
 				// Ensure that Intersection-Edge is not a Null-Line.
 				// If it is a Null-Line, detected Intersection is a False-Positive.
 				if (!result.getPolyLine().isNullLine()) {

CityDoctorParent/CityDoctorValidation/src/test/java/de/hft/stuttgart/citydoctor2/checks/util/GeometryTestUtils.java

@@ -21,6 +21,7 @@ package de.hft.stuttgart.citydoctor2.checks.util;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.StringJoiner;
 
 import de.hft.stuttgart.citydoctor2.datastructure.ConcretePolygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Geometry;

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/ListErrorVisitor.java

@@ -43,6 +43,7 @@ import de.hft.stuttgart.citydoctor2.check.error.UnknownCheckError;
 import de.hft.stuttgart.citydoctor2.datastructure.Edge;
 import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
 import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
+import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection;
 import javafx.scene.paint.Color;
 
 public class ListErrorVisitor implements ErrorVisitor {
@@ -171,7 +172,11 @@ public class ListErrorVisitor implements ErrorVisitor {
 
 	@Override
 	public void visit(SolidSelfIntError err) {
-		// nothing to display for now
+		controller.clearHighlights();
+		for (PolygonIntersection intersection : err.getIntersections()) {
+			controller.addHighlight(intersection.getP1(), geom);
+			controller.addHighlight(intersection.getP2(), geom);
+		}
 	}
 
 	@Override
@@ -208,22 +213,22 @@ public class ListErrorVisitor implements ErrorVisitor {
 
 	@Override
 	public void visit(NotCeilingError err) {
-		// nothing to display
+		controller.highlight(err.getPolygon(), geom);
 	}
 
 	@Override
 	public void visit(NotFloorError err) {
-		// nothing to display
+		controller.highlight(err.getPolygon(), geom);
 	}
 
 	@Override
 	public void visit(NotWallError err) {
-		// nothing to display
+		controller.highlight(err.getPolygon(), geom);
 	}
 
 	@Override
 	public void visit(NotGroundError err) {
-		// nothing to display
+		controller.highlight(err.getPolygon(), geom);
 	}
 
 	@Override

CityDoctorParent/Extensions/CityDoctorGUI/src/main/java/de/hft/stuttgart/citydoctor2/gui/tree/ErrorItemVisitor.java

@@ -39,16 +39,23 @@ import de.hft.stuttgart.citydoctor2.check.error.SurfaceUnfragmentedError;
 import de.hft.stuttgart.citydoctor2.check.error.DegeneratedRingError;
 import de.hft.stuttgart.citydoctor2.check.error.TooFewPolygonsError;
 import de.hft.stuttgart.citydoctor2.check.error.UnknownCheckError;
+import de.hft.stuttgart.citydoctor2.datastructure.ConcretePolygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Edge;
+import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
+import de.hft.stuttgart.citydoctor2.datastructure.LinearRing.LinearRingType;
 import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
 import de.hft.stuttgart.citydoctor2.gui.CheckStatus;
+import de.hft.stuttgart.citydoctor2.math.Triangle3d;
+import de.hft.stuttgart.citydoctor2.utils.Localization;
+import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection;
+import de.hft.stuttgart.citydoctor2.utils.PolygonIntersection.IntersectionType;
 import javafx.scene.control.TreeItem;
 
 public class ErrorItemVisitor implements ErrorVisitor {
 
-	private static final String NAME_OF_ATTRIBUTE = "Name of Attribute: ";
-	private static final String CHILD_ID = "ChildId: ";
+	private static String nameOfAttribute = Localization.getText("ErrorItemVisitor.nameOfAttribute") + ": ";
+	private static String childId = Localization.getText("ErrorItemVisitor.childId") + ": ";
 	private final TreeItem<Renderable> root;
 
 	public ErrorItemVisitor(TreeItem<Renderable> root) {
@@ -74,7 +81,7 @@ public class ErrorItemVisitor implements ErrorVisitor {
 	@Override
 	public void visit(MultipleConnectedComponentsError err) {
 		for (int i = 0; i < err.getComponents().size(); i++) {
-			TextNode textNode = new TextNode("Component " + i);
+			TextNode textNode = new TextNode(Localization.getText("ErrorItemVisitor.component") + " " + i);
 			TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 			root.getChildren().add(textItem);
 			List<Polygon> component = err.getComponents().get(i);
@@ -99,7 +106,7 @@ public class ErrorItemVisitor implements ErrorVisitor {
 		TreeItem<Renderable> vertexItem = new TreeItem<>(vertexNode);
 		root.getChildren().add(vertexItem);
 		for (int i = 0; i < err.getComponents().size(); i++) {
-			TextNode textNode = new TextNode("Component " + i);
+			TextNode textNode = new TextNode(Localization.getText("ErrorItemVisitor.component") + " " + i);
 			TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 			root.getChildren().add(textItem);
 			List<Polygon> component = err.getComponents().get(i);
@@ -207,7 +214,8 @@ public class ErrorItemVisitor implements ErrorVisitor {
 		TreeItem<Renderable> polyItem = new TreeItem<>(polyNode);
 		root.getChildren().add(polyItem);
 
-		TextNode textNode = new TextNode("Deviation: " + err.getDeviation());
+		TextNode textNode = new TextNode(
+				Localization.getText("ErrorItemVisitor.deviation") + ": " + err.getDeviation());
 		TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 		root.getChildren().add(textItem);
 	}
@@ -222,7 +230,8 @@ public class ErrorItemVisitor implements ErrorVisitor {
 		TreeItem<Renderable> vertexItem = new TreeItem<>(vertexNode);
 		root.getChildren().add(vertexItem);
 
-		TextNode textNode = new TextNode("Distance: " + err.getDistance() + "m");
+		TextNode textNode = new TextNode(
+				Localization.getText("ErrorItemVisitor.distance") + ": " + err.getDistance() + "m");
 		TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 		root.getChildren().add(textItem);
 
@@ -237,12 +246,48 @@ public class ErrorItemVisitor implements ErrorVisitor {
 
 	@Override
 	public void visit(SolidSelfIntError err) {
-		PolygonNode polyNode1 = new PolygonNode(err.getIntersections().get(0).getP1(), CheckStatus.NOT_CHECKED);
+		List<PolygonIntersection> intersections = err.getIntersections();
+		for (int i = 0; i < intersections.size(); i++) {
+			PolygonIntersection pi = intersections.get(i);
+			TextNode intersectionNode = new TextNode(Localization.getText("ErrorItemVisitor.intersection") + " " + i);
+			TreeItem<Renderable> intersectionItem = new TreeItem<>(intersectionNode);
+			root.getChildren().add(intersectionItem);
+
+			PolygonNode polyNode1 = new PolygonNode(pi.getP1(), CheckStatus.NOT_CHECKED);
 			TreeItem<Renderable> polyItem1 = new TreeItem<>(polyNode1);
-		root.getChildren().add(polyItem1);
-		PolygonNode polyNode2 = new PolygonNode(err.getIntersections().get(0).getP2(), CheckStatus.NOT_CHECKED);
+			intersectionItem.getChildren().add(polyItem1);
+			PolygonNode polyNode2 = new PolygonNode(pi.getP2(), CheckStatus.NOT_CHECKED);
 			TreeItem<Renderable> polyItem2 = new TreeItem<>(polyNode2);
-		root.getChildren().add(polyItem2);
+			intersectionItem.getChildren().add(polyItem2);
+			PolygonIntersection intersection = err.getIntersections().get(0);
+			if (intersection.getType() == IntersectionType.TRIANGLES) {
+				TextNode trianglesNode = new TextNode(Localization.getText("ErrorItemVisitor.triangles"));
+				TreeItem<Renderable> trianglesItem = new TreeItem<>(trianglesNode);
+				intersectionItem.getChildren().add(trianglesItem);
+
+				ConcretePolygon c = createPolygonForTriangle(intersection.getT1());
+				PolygonNode pN1 = new PolygonNode(c, CheckStatus.NOT_CHECKED);
+				TreeItem<Renderable> pI1 = new TreeItem<>(pN1);
+				trianglesItem.getChildren().add(pI1);
+
+				ConcretePolygon c2 = createPolygonForTriangle(intersection.getT2());
+				PolygonNode pN2 = new PolygonNode(c2, CheckStatus.NOT_CHECKED);
+				TreeItem<Renderable> pI2 = new TreeItem<>(pN2);
+				trianglesItem.getChildren().add(pI2);
+			}
+		}
+	}
+
+	private ConcretePolygon createPolygonForTriangle(Triangle3d t) {
+		ConcretePolygon c = new ConcretePolygon();
+		LinearRing extRing = new LinearRing(LinearRingType.EXTERIOR);
+		Vertex start = new Vertex(t.getP1());
+		extRing.getVertices().add(start);
+		extRing.getVertices().add(new Vertex(t.getP2()));
+		extRing.getVertices().add(new Vertex(t.getP3()));
+		extRing.getVertices().add(start);
+		c.setExteriorRing(extRing);
+		return c;
 	}
 
 	@Override
@@ -288,7 +333,7 @@ public class ErrorItemVisitor implements ErrorVisitor {
 
 	@Override
 	public void visit(PointTouchesEdgeError err) {
-		TextNode textNode = new TextNode("Point touches edge");
+		TextNode textNode = new TextNode(Localization.getText("ErrorItemVisitor.pointTouchesEdge"));
 		TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 		root.getChildren().add(textItem);
 
@@ -347,14 +392,15 @@ public class ErrorItemVisitor implements ErrorVisitor {
 
 	@Override
 	public void visit(SurfaceUnfragmentedError err) {
-		TextNode textNode = new TextNode("Deviation: " + err.getAngleDeviation());
+		TextNode textNode = new TextNode(
+				Localization.getText("ErrorItemVisitor.deviation") + ": " + err.getAngleDeviation());
 		TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 		root.getChildren().add(textItem);
 	}
 
 	@Override
 	public void visit(DegeneratedRingError err) {
-		TextNode textNode = new TextNode("Type: degenerated ring");
+		TextNode textNode = new TextNode(Localization.getText("ErrorItemVisitor.degeneratedRing"));
 		TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 		root.getChildren().add(textItem);
 
@@ -366,11 +412,11 @@ public class ErrorItemVisitor implements ErrorVisitor {
 	@Override
 	public void visit(AttributeMissingError err) {
 		if (!err.getChildId().isEmpty()) {
-			TextNode textNode = new TextNode(CHILD_ID + err.getChildId());
+			TextNode textNode = new TextNode(childId + err.getChildId());
 			TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 			root.getChildren().add(textItem);
 		}
-		TextNode nameNode = new TextNode(NAME_OF_ATTRIBUTE + err.getNameOfAttribute());
+		TextNode nameNode = new TextNode(nameOfAttribute + err.getNameOfAttribute());
 		TreeItem<Renderable> nameItem = new TreeItem<>(nameNode);
 		root.getChildren().add(nameItem);
 
@@ -379,11 +425,11 @@ public class ErrorItemVisitor implements ErrorVisitor {
 	@Override
 	public void visit(AttributeValueWrongError err) {
 		if (!err.getChildId().isEmpty()) {
-			TextNode textNode = new TextNode(CHILD_ID + err.getChildId());
+			TextNode textNode = new TextNode(childId + err.getChildId());
 			TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 			root.getChildren().add(textItem);
 		}
-		TextNode nameNode = new TextNode(NAME_OF_ATTRIBUTE + err.getNameOfAttribute());
+		TextNode nameNode = new TextNode(nameOfAttribute + err.getNameOfAttribute());
 		TreeItem<Renderable> nameItem = new TreeItem<>(nameNode);
 		root.getChildren().add(nameItem);
 	}
@@ -391,11 +437,11 @@ public class ErrorItemVisitor implements ErrorVisitor {
 	@Override
 	public void visit(AttributeInvalidError err) {
 		if (!err.getChildId().isEmpty()) {
-			TextNode textNode = new TextNode(CHILD_ID + err.getChildId());
+			TextNode textNode = new TextNode(childId + err.getChildId());
 			TreeItem<Renderable> textItem = new TreeItem<>(textNode);
 			root.getChildren().add(textItem);
 		}
-		TextNode nameNode = new TextNode(NAME_OF_ATTRIBUTE + err.getNameOfAttribute());
+		TextNode nameNode = new TextNode(nameOfAttribute + err.getNameOfAttribute());
 		TreeItem<Renderable> nameItem = new TreeItem<>(nameNode);
 		root.getChildren().add(nameItem);
 	}

CityDoctorParent/pom.xml

 <?xml version="1.0" encoding="utf-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0"
->
+<project xmlns="http://maven.apache.org/POM/4.0.0">
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>de.hft.stuttgart</groupId>
 	<artifactId>CityDoctorParent</artifactId>
@@ -221,7 +220,7 @@
 			<dependency>
 				<groupId>org.locationtech.jts</groupId>
 				<artifactId>jts-core</artifactId>
-                <version>1.19.0</version>
+				<version>1.20.0</version>
 			</dependency>
 			<dependency>
 				<groupId>com.sun.xml.bind</groupId>
@@ -233,6 +232,11 @@
 				<artifactId>jakarta.xml.bind-api</artifactId>
 				<version>2.3.3</version>
 			</dependency>
+			<dependency>
+				<groupId>io.github.earcut4j</groupId>
+				<artifactId>earcut4j</artifactId>
+				<version>2.2.2</version>
+			</dependency>
 		</dependencies>
 	</dependencyManagement>
 	<dependencies>