From c24a91c42a2b2c693c3be87a0323bc036e54f5ab Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Thu, 8 Oct 2020 16:23:55 +0200
Subject: [PATCH] #1030 Check for intersecting axis and sweptarea

---
 src/ifcgeom/IfcGeomShapes.cpp | 41 ++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/ifcgeom/IfcGeomShapes.cpp b/src/ifcgeom/IfcGeomShapes.cpp
index 6ca75af910..8460f9aec4 100644
--- a/src/ifcgeom/IfcGeomShapes.cpp
+++ b/src/ifcgeom/IfcGeomShapes.cpp
@@ -355,7 +355,7 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcSurfaceOfRevolution* l, TopoDS
 bool IfcGeom::Kernel::convert(const IfcSchema::IfcRevolvedAreaSolid* l, TopoDS_Shape& shape) {
 	const double ang = l->Angle() * getValue(GV_PLANEANGLE_UNIT);
 
-	TopoDS_Face face;
+	TopoDS_Shape face;
 	if ( ! convert_face(l->SweptArea(),face) ) return false;
 
 	gp_Ax1 ax1;
@@ -370,6 +370,45 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcRevolvedAreaSolid* l, TopoDS_S
 		IfcGeom::Kernel::convert(l->Position(), trsf);
 	}
 
+
+	{
+		// https://github.com/IfcOpenShell/IfcOpenShell/issues/1030
+		// Check whether Axis does not intersect SweptArea
+
+		double min_dot = +std::numeric_limits<double>::infinity();
+		double max_dot = -std::numeric_limits<double>::infinity();
+
+		gp_Ax2 ax(ax1.Location(), gp::DZ(), ax1.Direction());
+
+		TopExp_Explorer exp(face, TopAbs_EDGE);
+		for (; exp.More(); exp.Next()) {
+			BRepAdaptor_Curve crv(TopoDS::Edge(exp.Current()));
+			GCPnts_QuasiUniformDeflection tessellater(crv, getValue(GV_PRECISION));
+
+			int n = tessellater.NbPoints();
+			for (int i = 1; i <= n; ++i) {
+				double d = ax.YDirection().XYZ().Dot(tessellater.Value(i).XYZ());
+				if (d < min_dot) {
+					min_dot = d;
+				}
+				if (d > max_dot) {
+					max_dot = d;
+				}
+			}
+		}
+
+		bool intersecting;
+		if (std::abs(min_dot) > std::abs(max_dot)) {
+			intersecting = max_dot > + getValue(GV_PRECISION);
+		} else {
+			intersecting = min_dot < - getValue(GV_PRECISION);
+		}
+
+		if (intersecting) {
+			Logger::Warning("Warning Axis and SweptArea intersecting", l);
+		}
+	}
+
 	if (ang >= M_PI * 2. - ALMOST_ZERO) {
 		shape = BRepPrimAPI_MakeRevol(face, ax1);
 	} else {