Adding default check for solids

switching proj4j to newer version not on maven
fixing an issue of polygon association when replacing a polygon in a geometry

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/CDPolygonNs.java

@@ -20,13 +20,74 @@ package de.hft.stuttgart.citydoctor2.edge;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+
+import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
 
 public class CDPolygonNs extends PolygonNs {
 	
 	private List<List<HalfEdge>> innerHalfEdges = new ArrayList<>();
+	
+	public static CDPolygonNs of(Polygon p, Map<Vertex, Coordinate3d> pointMap) {
+		List<List<Coordinate3d>> loopCoordinates = new ArrayList<>();
+		List<Coordinate3d> edgeExtRing = createCoordinatesFromRing(pointMap, p.getExteriorRing().getVertices());
+		loopCoordinates.add(edgeExtRing);
+		
+		for (LinearRing innerRing : p.getInnerRings()) {
+			List<Coordinate3d> edgeInnerRing = createCoordinatesFromRing(pointMap, innerRing.getVertices());
+			loopCoordinates.add(edgeInnerRing);
+		}
+		
+		List<List<HalfEdge>> halfEdges = new ArrayList<>();
+		for (List<Coordinate3d> ringCoordinates : loopCoordinates) {
+			List<HalfEdge> currHeList = createHalfEdgesFromCoordinates(ringCoordinates);
+			halfEdges.add(currHeList);
+		}
+		
+		return new CDPolygonNs(halfEdges, p);
+	}
+	
+	private static List<HalfEdge> createHalfEdgesFromCoordinates(List<Coordinate3d> ringCoordinates) {
+		List<HalfEdge> currHeList = new ArrayList<>();
+		HalfEdge prevHalfEdge = null;
+		for (int currCoordIndex = 1; currCoordIndex < ringCoordinates.size(); currCoordIndex++) {
+			int prevCoordIndex = currCoordIndex - 1;
+			Coordinate3d currCoord = ringCoordinates.get(currCoordIndex);
+			Coordinate3d prevCoord = ringCoordinates.get(prevCoordIndex);
+			HalfEdge e = new HalfEdge(prevCoord, currCoord);
+			if (prevHalfEdge != null) {
+				prevHalfEdge.setNext(e);
+			}
+			currHeList.add(e);
+			prevHalfEdge = e;
+		}
+		if (prevHalfEdge == null) {
+			throw new IllegalStateException("No half edges were created");
+		}
+		Coordinate3d start = ringCoordinates.get(0);
+		Coordinate3d end = ringCoordinates.get(ringCoordinates.size() - 1);
+		HalfEdge e = new HalfEdge(end, start);
+		prevHalfEdge.setNext(e);
+		e.setNext(currHeList.get(0));
+		currHeList.add(e);
+		return currHeList;
+	}
+	
+	private static List<Coordinate3d> createCoordinatesFromRing(Map<Vertex, Coordinate3d> pointMap,
+			List<Vertex> vertices) {
+		List<Coordinate3d> edgeRing = new ArrayList<>();
+		for (int i = 0; i < vertices.size() - 1; i++) {
+			Vertex v = vertices.get(i);
+			Coordinate3d c = pointMap.computeIfAbsent(v, key -> new Coordinate3d(key.getX(), key.getY(), key.getZ()));
+			edgeRing.add(c);
+		}
+		return edgeRing;
+	}
 
-	public CDPolygonNs(List<List<HalfEdge>> halfEdges) {
-		super(halfEdges.get(0));
+	public CDPolygonNs(List<List<HalfEdge>> halfEdges, Polygon original) {
+		super(halfEdges.get(0), original);
 		
 		for (int i = 1; i < halfEdges.size(); i++) {
 			List<HalfEdge> loopEdges = halfEdges.get(i);

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/EdgePolygon.java

@@ -22,15 +22,23 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+
 public class EdgePolygon extends BaseEntity {
 
+	private Polygon original;
 	private List<HalfEdge> halfEdges;
 	
-	public EdgePolygon(List<HalfEdge> halfEdges) {
+	public EdgePolygon(List<HalfEdge> halfEdges, Polygon original) {
 		for (HalfEdge he : halfEdges) {
 			addChild(he);
 		}
 		this.halfEdges = halfEdges;
+		this.original = original;
+	}
+	
+	public Polygon getOriginal() {
+		return original;
 	}
 
 	public GmPlane getPlane() {

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/IntersectPlanarPolygons.java

@@ -434,7 +434,7 @@ public class IntersectPlanarPolygons {
 				HalfEdge pStartHE = he;
 				HalfEdge pPartnerHE = pStartHE.getPartner();
 				boolean bothPolysShareThisEdge = false;
-				while (pStartHE != pPartnerHE && false == bothPolysShareThisEdge) {
+				while (pStartHE != pPartnerHE && !bothPolysShareThisEdge) {
 					if (pPartnerHE.getPolygon() == p1 || pPartnerHE.getPolygon() == p2) {
 						bothPolysShareThisEdge = true;
 					}

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/MeshSurface.java

@@ -24,7 +24,6 @@ import java.util.List;
 import java.util.Map;
 
 import de.hft.stuttgart.citydoctor2.datastructure.Geometry;
-import de.hft.stuttgart.citydoctor2.datastructure.LinearRing;
 import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
 import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
 
@@ -37,63 +36,20 @@ public class MeshSurface {
 		
 		Map<Vertex, Coordinate3d> pointMap = new IdentityHashMap<>();
 		for (Polygon p : geom.getPolygons()) {
-			List<List<Coordinate3d>> loopCoordinates = new ArrayList<>();
-			List<Coordinate3d> edgeExtRing = createCoordinatesFromRing(pointMap, p.getExteriorRing().getVertices());
-			loopCoordinates.add(edgeExtRing);
-			
-			for (LinearRing innerRing : p.getInnerRings()) {
-				List<Coordinate3d> edgeInnerRing = createCoordinatesFromRing(pointMap, innerRing.getVertices());
-				loopCoordinates.add(edgeInnerRing);
-			}
-			
-			List<List<HalfEdge>> halfEdges = new ArrayList<>();
-			for (List<Coordinate3d> ringCoordinates : loopCoordinates) {
-				List<HalfEdge> currHeList = createHalfEdgesFromCoordinates(ringCoordinates);
-				halfEdges.add(currHeList);
-			}
-			
-			CDPolygonNs newPolygon = new CDPolygonNs(halfEdges);
-			polygonList.add(newPolygon);
+			CDPolygonNs poly = CDPolygonNs.of(p, pointMap);
+			polygonList.add(poly);
+//			HalfEdge firstHalfEdge = poly.getFirstHalfEdge();
+//			System.out.println();
+//			System.out.println(firstHalfEdge.getStart());
+//			System.out.println(firstHalfEdge.getEnd());
+//			HalfEdge next = firstHalfEdge.getNext();
+//			while (next != firstHalfEdge) {
+//				System.out.println(next.getEnd());
+//				next = next.getNext();
+//			}
 		}
 		return new MeshSurface(polygonList);
 	}
-
-	private static List<Coordinate3d> createCoordinatesFromRing(Map<Vertex, Coordinate3d> pointMap,
-			List<Vertex> vertices) {
-		List<Coordinate3d> edgeRing = new ArrayList<>();
-		for (int i = 0; i < vertices.size() - 1; i++) {
-			Vertex v = vertices.get(i);
-			Coordinate3d c = pointMap.computeIfAbsent(v, key -> new Coordinate3d(key.getX(), key.getY(), key.getZ()));
-			edgeRing.add(c);
-		}
-		return edgeRing;
-	}
-
-	private static List<HalfEdge> createHalfEdgesFromCoordinates(List<Coordinate3d> ringCoordinates) {
-		List<HalfEdge> currHeList = new ArrayList<>();
-		HalfEdge prevHalfEdge = null;
-		for (int currCoordIndex = 1; currCoordIndex < ringCoordinates.size(); currCoordIndex++) {
-			int prevCoordIndex = currCoordIndex - 1;
-			Coordinate3d currCoord = ringCoordinates.get(currCoordIndex);
-			Coordinate3d prevCoord = ringCoordinates.get(prevCoordIndex);
-			HalfEdge e = new HalfEdge(prevCoord, currCoord);
-			if (prevHalfEdge != null) {
-				prevHalfEdge.setNext(e);
-			}
-			currHeList.add(e);
-			prevHalfEdge = e;
-		}
-		if (prevHalfEdge == null) {
-			throw new IllegalStateException("No half edges were created");
-		}
-		Coordinate3d start = ringCoordinates.get(0);
-		Coordinate3d end = ringCoordinates.get(ringCoordinates.size() - 1);
-		HalfEdge e = new HalfEdge(end, start);
-		prevHalfEdge.setNext(e);
-		e.setNext(currHeList.get(0));
-		currHeList.add(e);
-		return currHeList;
-	}
 	
 	public MeshSurface(List<CDPolygonNs> polygons) {
 		this.polygons = polygons;

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/PolygonNs.java

@@ -20,10 +20,12 @@ package de.hft.stuttgart.citydoctor2.edge;
 
 import java.util.List;
 
+import de.hft.stuttgart.citydoctor2.datastructure.Polygon;
+
 public class PolygonNs extends EdgePolygon {
 
-	public PolygonNs(List<HalfEdge> list) {
-		super(list);
+	public PolygonNs(List<HalfEdge> list, Polygon original) {
+		super(list, original);
 	}
 
 }

CityDoctorParent/CityDoctorEdge/src/main/java/de/hft/stuttgart/citydoctor2/edge/PolygonPolygonIntersection.java

@@ -51,5 +51,11 @@ public class PolygonPolygonIntersection {
 	public EdgePolygon getPolygon2() {
 		return p2;
 	}
+	
+	@Override
+	public String toString() {
+		return "PolygonPolygonIntersection [p1=" + p1 + ", p2=" + p2 + ", polyLine=" + polyLine + ", type=" + type
+				+ "]";
+	}
 
 }

CityDoctorParent/CityDoctorEdge/src/test/java/de/hft/stuttgart/citydoctor2/edge/IntersectionErrorsTest.java

+/*-
+ *  Copyright 2020 Beuth Hochschule für Technik Berlin, Hochschule für Technik Stuttgart
+ * 
+ *  This file is part of CityDoctor2.
+ *
+ *  CityDoctor2 is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  CityDoctor2 is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with CityDoctor2.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package de.hft.stuttgart.citydoctor2.edge;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import org.junit.Test;
+
+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.datastructure.LinearRing;
+import de.hft.stuttgart.citydoctor2.datastructure.LinearRing.LinearRingType;
+import de.hft.stuttgart.citydoctor2.datastructure.Lod;
+import de.hft.stuttgart.citydoctor2.datastructure.Vertex;
+
+public class IntersectionErrorsTest {
+
+	@Test
+	public void testWrongIntersection() {
+		Geometry geom = new Geometry(GeometryType.SOLID, Lod.LOD1);
+
+		ConcretePolygon p1 = new ConcretePolygon();
+
+		LinearRing ext1 = new LinearRing(LinearRingType.EXTERIOR);
+		p1.setExteriorRing(ext1);
+		
+		/*
+		Vertex [x=3515051.7, y=5405988.05, z=246.67]
+				Vertex [x=3515047.52, y=5405985.1, z=246.67]
+				Vertex [x=3515049.03, y=5405978.98, z=246.67]
+				Vertex [x=3515054.29, y=5405983.65, z=246.67]
+				Vertex [x=3515051.7, y=5405988.05, z=246.67]
+				*/
+		
+
+		Vertex v1 = new Vertex(3515047.52, 5405985.1, 246.67);
+		Vertex v2 = new Vertex(3515049.03, 5405978.98, 246.67);
+		Vertex v3 = new Vertex(3515054.29, 5405983.65, 246.67);
+		Vertex v4 = new Vertex(3515051.7, 5405988.05, 246.67);
+
+		ext1.addVertex(v1);
+		ext1.addVertex(v2);
+		ext1.addVertex(v3);
+		ext1.addVertex(v4);
+		ext1.addVertex(v1);
+
+		ConcretePolygon p2 = new ConcretePolygon();
+		LinearRing ext2 = new LinearRing(LinearRingType.EXTERIOR);
+		p2.setExteriorRing(ext2);
+
+		/*
+		 		Vertex [x=3515049.03, y=5405978.98, z=237.903218]
+				Vertex [x=3515054.29, y=5405983.65, z=237.903218]
+				Vertex [x=3515054.29, y=5405983.65, z=246.67]
+				Vertex [x=3515049.03, y=5405978.98, z=246.67]
+				Vertex [x=3515049.03, y=5405978.98, z=237.903218] 
+		 */
+		
+		Vertex v5 = new Vertex(3515049.03, 5405978.98, 237.903218);
+		Vertex v6 = new Vertex(3515054.29, 5405983.65, 237.903218);
+		Vertex v7 = v3;
+		Vertex v8 = v2;
+
+		ext2.addVertex(v5);
+		ext2.addVertex(v6);
+		ext2.addVertex(v7);
+		ext2.addVertex(v8);
+		ext2.addVertex(v5);
+
+		geom.addPolygon(p1);
+		geom.addPolygon(p2);
+
+		geom.prepareForChecking();
+		
+		
+		System.out.println();
+		for (Vertex v : p1.getExteriorRing().getVertices()) {
+			System.out.println(v);
+		}
+		System.out.println();
+		for (Vertex v : p2.getExteriorRing().getVertices()) {
+			System.out.println(v);
+		}
+		
+		MeshSurface meshSurface = MeshSurface.of(geom);
+		List<CDPolygonNs> polygons = meshSurface.getPolygons();
+		assertEquals(2, polygons.size());
+		
+		CDPolygonNs edgePoly1 = meshSurface.getPolygons().get(0);
+		CDPolygonNs edgePoly2 = meshSurface.getPolygons().get(1);
+		
+		
+		List<PolygonPolygonIntersection> intersectPolygons = IntersectPlanarPolygons.intersectPolygons(edgePoly1, edgePoly2, 0.000001, 0.001);
+		assertTrue(intersectPolygons.isEmpty());
+	}
+}

CityDoctorParent/CityDoctorModel/pom.xml

@@ -58,7 +58,7 @@
 			<artifactId>snakeyaml</artifactId>
 		</dependency>
 		<dependency>
-			<groupId>org.osgeo</groupId>
+			<groupId>org.locationtech.proj4j</groupId>
 			<artifactId>proj4j</artifactId>
 		</dependency>
 	</dependencies>

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/check/HealingMethod.java

@@ -19,6 +19,7 @@
 package de.hft.stuttgart.citydoctor2.check;
 
 import de.hft.stuttgart.citydoctor2.check.error.AllPolygonsWrongOrientationError;
+import de.hft.stuttgart.citydoctor2.check.error.AttributeMissingError;
 import de.hft.stuttgart.citydoctor2.check.error.ConsecutivePointSameError;
 import de.hft.stuttgart.citydoctor2.check.error.DependenciesNotMetError;
 import de.hft.stuttgart.citydoctor2.check.error.MultipleConnectedComponentsError;
@@ -187,6 +188,10 @@ public interface HealingMethod {
 	default boolean visit(SurfaceUnfragmentedError err, ModificationListener l) {
 		return false;
 	}
+	
+	default boolean visit(AttributeMissingError err, ModificationListener l) {
+		return false;
+	}
 
 	public HealingMethod createNew();
 

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/CityDoctorModel.java

@@ -371,4 +371,20 @@ public class CityDoctorModel {
 		}
 		buildings.set(index, (Building) nextFeature);
 	}
+
+	public void addCityObject(CityObject co) {
+		if (co instanceof Building) {
+			buildings.add((Building) co);
+		} else if (co instanceof BridgeObject) {
+			bridges.add((BridgeObject) co);
+		} else if (co instanceof TransportationObject) {
+			roads.add((TransportationObject) co);
+		} else if (co instanceof Vegetation) {
+			vegetation.add((Vegetation) co);
+		} else if (co instanceof LandObject) {
+			land.add((LandObject) co);
+		} else if (co instanceof WaterObject) {
+			water.add((WaterObject) co);
+		}
+	}
 }

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/ConcretePolygon.java

@@ -53,6 +53,11 @@ public class ConcretePolygon extends Polygon {
 	 * 
 	 * @see de.hft.stuttgart.citydoctor2.datastructure.Polygon#calculateNormal()
 	 */
+	@Override
+	public Vector3d calculateNormalNormalized() {
+		return exterior.calculateNormalNormalized();
+	}
+	
 	@Override
 	public Vector3d calculateNormal() {
 		return exterior.calculateNormal();

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/Geometry.java

@@ -89,6 +89,16 @@ public class Geometry extends GmlElement {
 	public void addPolygon(Polygon cdPoly) {
 		polygons.add(cdPoly);
 		cdPoly.setParent(this);
+		// set part of boundary surface or building installation or both
+		if (parent instanceof BoundarySurface) {
+			BoundarySurface bs = (BoundarySurface) parent;
+			cdPoly.setPartOfSurface(bs);
+			if (bs.getParent() instanceof BuildingInstallation) {
+				cdPoly.setPartOfInstallation((BuildingInstallation) bs.getParent());
+			}
+		} else if (parent instanceof BuildingInstallation) {
+			cdPoly.setPartOfInstallation((BuildingInstallation) parent);
+		}
 	}
 
 	public void updateEdges() {

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/LinearRing.java

@@ -59,7 +59,7 @@ public class LinearRing extends GmlElement {
 		// project to 2d ring
 		List<Vector2d> projectedRing = new ArrayList<>();
 		Vector2d point;
-		Vector3d normal = calculateNormal();
+		Vector3d normal = calculateNormalNormalized();
 
 		double x = Math.abs(normal.getX());
 		double y = Math.abs(normal.getY());
@@ -135,7 +135,7 @@ public class LinearRing extends GmlElement {
 	 * 
 	 * @return the normal as a normalized vector
 	 */
-	public Vector3d calculateNormal() {
+	public Vector3d calculateNormalNormalized() {
 		double[] coords = new double[3];
 		for (int i = 0; i < vertices.size() - 1; i++) {
 			Vertex current = vertices.get(i + 0);
@@ -161,6 +161,38 @@ public class LinearRing extends GmlElement {
 		v.normalize();
 		return v;
 	}
+	
+	/**
+	 * Calculates the normal vector of the ring. Method by Newell. If the Newell
+	 * method would return a (0, 0, 0) vector a cross product is formed from the
+	 * first 3 vertices. If there are no 3 vertices available (1, 0, 0) is returned.
+	 * 
+	 * @return the normal vector
+	 */
+	public Vector3d calculateNormal() {
+		double[] coords = new double[3];
+		for (int i = 0; i < vertices.size() - 1; i++) {
+			Vertex current = vertices.get(i + 0);
+			Vertex next = vertices.get(i + 1);
+			coords[0] += (current.getZ() + next.getZ()) * (current.getY() - next.getY());
+			coords[1] += (current.getX() + next.getX()) * (current.getZ() - next.getZ());
+			coords[2] += (current.getY() + next.getY()) * (current.getX() - next.getX());
+		}
+
+		if (coords[0] == 0 && coords[1] == 0 && coords[2] == 0) {
+			// no valid normal vector found
+			if (vertices.size() < 3) {
+				// no three points, return x-axis
+				return new Vector3d(1, 0, 0);
+			}
+
+			Vertex v1 = vertices.get(0);
+			Vertex v2 = vertices.get(1);
+			Vertex v3 = vertices.get(2);
+			return calculateNormalWithCross(v1, v2, v3);
+		}
+		return new Vector3d(coords);
+	}
 
 	private Vector3d calculateNormalWithCross(Vertex v1, Vertex v2, Vertex v3) {
 		Vector3d dir1 = v2.minus(v1);

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/LinkedPolygon.java

@@ -132,6 +132,11 @@ public class LinkedPolygon extends Polygon {
 		poly.clearCheckResults();
 	}
 
+	@Override
+	public Vector3d calculateNormalNormalized() {
+		return poly.calculateNormalNormalized();
+	}
+	
 	@Override
 	public Vector3d calculateNormal() {
 		return poly.calculateNormal();

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/Polygon.java

@@ -33,6 +33,7 @@ public abstract class Polygon extends GmlElement {
 
 	private static final long serialVersionUID = -613942946364706513L;
 
+	public abstract Vector3d calculateNormalNormalized();
 	public abstract Vector3d calculateNormal();
 
 	public abstract TesselatedPolygon tesselate();

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/mapper/GeometryMapper.java

@@ -39,8 +39,8 @@ import org.citygml4j.model.gml.geometry.primitives.PosOrPointPropertyOrPointRep;
 import org.citygml4j.model.gml.geometry.primitives.SolidProperty;
 import org.citygml4j.model.gml.geometry.primitives.SurfaceProperty;
 import org.citygml4j.util.walker.GeometryWalker;
-import org.osgeo.proj4j.BasicCoordinateTransform;
-import org.osgeo.proj4j.ProjCoordinate;
+import org.locationtech.proj4j.BasicCoordinateTransform;
+import org.locationtech.proj4j.ProjCoordinate;
 
 import de.hft.stuttgart.citydoctor2.datastructure.BoundarySurface;
 import de.hft.stuttgart.citydoctor2.datastructure.BuildingInstallation;
@@ -171,7 +171,9 @@ public class GeometryMapper extends GeometryWalker {
 			ConcretePolygon cdPoly) {
 		if (gmlPoly.isSetId()) {
 			cdPoly.setGmlId(new GmlId(gmlPoly.getId()));
-			polygons.put(gmlPoly.getId(), cdPoly);
+			if (polygons.put(gmlPoly.getId(), cdPoly) != null) {
+				logger.warn("Found already existing polygon ID {}, duplicate IDs are not valid", gmlPoly.getId());
+			}
 		}
 	}
 

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

@@ -38,7 +38,7 @@ public class Polygon2d {
 	private List<Ring2d> innerRings;
 
 	public static Polygon2d withProjection(Polygon poly) {
-		Vector3d normal = poly.calculateNormal();
+		Vector3d normal = poly.calculateNormalNormalized();
 		int[] axis = getProjectionAxis(normal);
 		return projectTo2D(poly, axis);
 	}

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

@@ -33,7 +33,7 @@ public class PolygonUtils {
 	}
 
 	public static Matrix3x3d calculateRotationMatrix(Polygon p) {
-		Vector3d normal = p.calculateNormal();
+		Vector3d normal = p.calculateNormalNormalized();
 		Vector3d zAxis = new Vector3d(0d, 0d, 1d);