diff --git a/src/ifcgeom/AbstractKernel.cpp b/src/ifcgeom/AbstractKernel.cpp
index e4917fe679..7b7ee93387 100644
--- a/src/ifcgeom/AbstractKernel.cpp
+++ b/src/ifcgeom/AbstractKernel.cpp
@@ -2,6 +2,7 @@
 
 #include "../ifcgeom/IfcGeomElement.h"
 #include "../ifcgeom/ConversionSettings.h"
+#include "../ifcgeom/abstract_mapping.h"
 
 #ifdef IFOPSH_WITH_OPENCASCADE
 #include "../ifcgeom/kernels/opencascade/OpenCascadeKernel.h"
@@ -38,8 +39,109 @@ const Settings& ifcopenshell::geometry::kernels::AbstractKernel::settings() cons
 	return settings_;
 }
 
-ifcopenshell::geometry::kernels::AbstractKernel* ifcopenshell::geometry::kernels::construct(const std::string& geometry_library, const Settings& conv_settings) {
-	const std::string geometry_library_lower = boost::to_lower_copy(geometry_library);
+
+bool is_valid_for_kernel(const ifcopenshell::geometry::kernels::AbstractKernel* k, const IfcGeom::ConversionResult& shp) {
+#ifdef IFOPSH_WITH_OPENCASCADE
+	if (k->geometry_library() == "opencascade") {
+		return dynamic_cast<ifcopenshell::geometry::OpenCascadeShape*>(shp.Shape().get()) != nullptr;
+	}
+#endif
+#ifdef IFOPSH_WITH_CGAL
+	if (k->geometry_library() == "cgal-simple") {
+		return dynamic_cast<ifcopenshell::geometry::SimpleCgalShape*>(shp.Shape().get()) != nullptr;
+	}
+	if (k->geometry_library() == "cgal") {
+		return dynamic_cast<ifcopenshell::geometry::CgalShape*>(shp.Shape().get()) != nullptr;
+	}
+#endif
+}
+
+class HybridKernel : public ifcopenshell::geometry::kernels::AbstractKernel {
+	std::vector<AbstractKernel*> kernels_;
+	ifcopenshell::geometry::abstract_mapping* mapping_;
+public:
+	HybridKernel(const std::string& name, IfcParse::IfcFile* file, Settings& settings, std::vector<AbstractKernel*> kernels)
+		: AbstractKernel(name, settings)
+		, kernels_(kernels)
+		, mapping_(ifcopenshell::geometry::impl::mapping_implementations().construct(file, settings))
+	{}
+	virtual bool convert(const taxonomy::ptr item, IfcGeom::ConversionResults& rs) {
+		auto ops = mapping_->find_openings(item->instance->as<IfcUtil::IfcBaseEntity>());
+		bool has_openings = ops && ops->size();
+		for (auto& k : kernels_) {
+#ifdef IFOPSH_WITH_CGAL
+			if (has_openings && dynamic_cast<ifcopenshell::geometry::kernels::SimpleCgalKernel*>(k)) {
+				// @todo this would fail later on in the find_openings() call, because we have a
+				// SimpleCgalShape which cannot be used on a kernel that supports booleans.
+				// @todo 1 implement the translation between various conversion result shapes
+				// @todo 2 fold the boolean result openings into the taxonomy item. This should be possible
+				//         now that we have shared_ptr<item> and caching in place. So the inability
+				//         to instance wouldn't matter as much.
+				continue;
+			}
+#endif
+			bool success = false;
+			try {
+				success = k->convert(item, rs);
+			} catch(...) {}
+			if (success) {
+				return true;
+			}
+		}
+		return false;
+	}
+	virtual bool apply_layerset(IfcGeom::ConversionResults& items, const ifcopenshell::geometry::layerset_information& layers) {
+		for (auto& k : kernels_) {
+			bool success = false;
+			try {
+				success = k->apply_layerset(items, layers);
+			} catch (...) {}
+			if (success) {
+				return true;
+			}
+		}
+		return false;
+	}
+	virtual bool apply_folded_layerset(IfcGeom::ConversionResults& items, const ifcopenshell::geometry::layerset_information& layers, const std::map<IfcUtil::IfcBaseEntity*, ifcopenshell::geometry::layerset_information>& folds) {
+		for (auto& k : kernels_) {
+			bool success = false;
+			try {
+				success = k->apply_folded_layerset(items, layers, folds);
+			} catch (...) {}
+			if (success) {
+				return true;
+			}
+		}
+		return false;
+	}
+	virtual bool convert_openings(const IfcUtil::IfcBaseEntity* entity, const std::vector<std::pair<taxonomy::ptr, ifcopenshell::geometry::taxonomy::matrix4>>& openings,
+		const IfcGeom::ConversionResults& entity_shapes, const ifcopenshell::geometry::taxonomy::matrix4& entity_trsf, IfcGeom::ConversionResults& cut_shapes)
+	{
+		for (auto& k : kernels_) {
+			bool is_valid = true;
+			for (auto& s : entity_shapes) {
+				if (!is_valid_for_kernel(k, s)) {
+					is_valid = false;
+					break;
+				}
+			}
+			if (!is_valid) {
+				continue;
+			}
+			bool success = false;
+			try {
+				success = k->convert_openings(entity, openings, entity_shapes, entity_trsf, cut_shapes);
+			} catch (...) {}
+			if (success) {
+				return true;
+			}
+		}
+		return false;
+	}
+};
+
+ifcopenshell::geometry::kernels::AbstractKernel* ifcopenshell::geometry::kernels::construct(IfcParse::IfcFile* file, const std::string& geometry_library, Settings& conv_settings) {
+	std::string geometry_library_lower = boost::to_lower_copy(geometry_library);
 
 #ifdef IFOPSH_WITH_OPENCASCADE
 	if (geometry_library_lower == "opencascade") {
@@ -56,6 +158,44 @@ ifcopenshell::geometry::kernels::AbstractKernel* ifcopenshell::geometry::kernels
 		return new SimpleCgalKernel(conv_settings);
 	}
 #endif
+
+	if (geometry_library_lower.rfind("hybrid-", 0) == 0) {
+		geometry_library_lower = geometry_library_lower.substr(strlen("hybrid"));
+		std::vector<AbstractKernel*> kernels;
+		while (!geometry_library_lower.empty()) {
+			if (geometry_library_lower.find("-", 0) == 0) {
+				geometry_library_lower = geometry_library_lower.substr(strlen("-"));
+			} else {
+				throw IfcParse::IfcException("Invalid hybrid kernel " + geometry_library);
+			}
+			auto n = kernels.size();
+#ifdef IFOPSH_WITH_OPENCASCADE
+			if (geometry_library_lower.find("opencascade", 0) == 0) {
+				kernels.push_back(new IfcGeom::OpenCascadeKernel(conv_settings));
+				geometry_library_lower = geometry_library_lower.substr(strlen("opencascade"));
+			}
+#endif
+
+#ifdef IFOPSH_WITH_CGAL
+			if (geometry_library_lower.find("cgal-simple", 0) == 0) {
+				kernels.push_back(new SimpleCgalKernel(conv_settings));
+				geometry_library_lower = geometry_library_lower.substr(strlen("cgal-simple"));
+			}
+
+			if (geometry_library_lower.find("cgal", 0) == 0) {
+				kernels.push_back(new CgalKernel(conv_settings));
+				geometry_library_lower = geometry_library_lower.substr(strlen("cgal"));
+			}
+#endif
+			if (kernels.size() != n + 1) {
+				throw IfcParse::IfcException("Invalid hybrid kernel " + geometry_library);
+			}
+		}
+
+		if (!kernels.empty()) {
+			return new HybridKernel(geometry_library, file, conv_settings, kernels);
+		}
+	}
 	
 	throw IfcParse::IfcException("No geometry kernel registered for " + geometry_library);
 }
diff --git a/src/ifcgeom/AbstractKernel.h b/src/ifcgeom/AbstractKernel.h
index 4c05b07c5b..fbc83438a8 100644
--- a/src/ifcgeom/AbstractKernel.h
+++ b/src/ifcgeom/AbstractKernel.h
@@ -19,16 +19,19 @@ namespace ifcopenshell { namespace geometry { namespace kernels {
 
 	class IFC_GEOM_API AbstractKernel {
 	protected:
-		std::string geometry_library;
+		std::string geometry_library_;
 		Settings settings_;
 
 	public:
 		AbstractKernel(const std::string& geometry_library, const Settings& settings)
-			: geometry_library(geometry_library)
+			: geometry_library_(geometry_library)
 			, settings_(settings) {}
 
-		bool convert(const taxonomy::ptr, IfcGeom::ConversionResults&);
+		virtual bool convert(const taxonomy::ptr, IfcGeom::ConversionResults&);
 		const Settings& settings() const;
+		const std::string& geometry_library() const {
+			return geometry_library_;
+		}
 
 		virtual bool convert_impl(const taxonomy::matrix4::ptr, IfcGeom::ConversionResults&) { throw std::runtime_error("Not implemented"); }
 		virtual bool convert_impl(const taxonomy::point3::ptr, IfcGeom::ConversionResults&) { throw std::runtime_error("Not implemented"); }
@@ -69,7 +72,7 @@ namespace ifcopenshell { namespace geometry { namespace kernels {
 
 	};
 
-	AbstractKernel* construct(const std::string& geometry_library, const Settings& conv_settings);
+	AbstractKernel* construct(IfcParse::IfcFile* file, const std::string& geometry_library, Settings& conv_settings);
 
 }
 }
diff --git a/src/ifcgeom/Converter.cpp b/src/ifcgeom/Converter.cpp
index ad73f5f3b4..20b5c9e753 100644
--- a/src/ifcgeom/Converter.cpp
+++ b/src/ifcgeom/Converter.cpp
@@ -9,7 +9,7 @@ ifcopenshell::geometry::Converter::Converter(const std::string& geometry_library
 	, settings_(s)
 {
 	mapping_ = impl::mapping_implementations().construct(file, settings_);
-	kernel_ = kernels::construct(geometry_library, mapping_->settings());
+	kernel_ = kernels::construct(file, geometry_library, mapping_->settings());
 }
 
 namespace {
diff --git a/src/ifcgeom/abstract_mapping.h b/src/ifcgeom/abstract_mapping.h
index 52f7394fd6..9601e54685 100644
--- a/src/ifcgeom/abstract_mapping.h
+++ b/src/ifcgeom/abstract_mapping.h
@@ -44,6 +44,7 @@ namespace geometry {
 		virtual IfcUtil::IfcBaseEntity* representation_of(const IfcUtil::IfcBaseEntity* product) = 0;
 
 		const Settings& settings() const { return settings_; }
+		Settings& settings() { return settings_; }
     };
 
 	namespace impl {