diff --git a/src/ifcgeom/mapping/IfcIndexedPolyCurve.cpp b/src/ifcgeom/mapping/IfcIndexedPolyCurve.cpp
index 535ec89aaa..f63725a997 100644
--- a/src/ifcgeom/mapping/IfcIndexedPolyCurve.cpp
+++ b/src/ifcgeom/mapping/IfcIndexedPolyCurve.cpp
@@ -50,8 +50,8 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcIndexedPolyCurve* inst) {
 		auto segments = *inst->Segments();
 		for (auto it = segments->begin(); it != segments->end(); ++it) {
 			auto segment = *it;
-			if (segment->declaration().is(IfcSchema::IfcLineIndex::Class())) {
-				IfcSchema::IfcLineIndex* line = (IfcSchema::IfcLineIndex*) segment;
+			if (segment->as<IfcSchema::IfcLineIndex>()) {
+				IfcSchema::IfcLineIndex* line = segment->as<IfcSchema::IfcLineIndex>();
 				std::vector<int> indices = *line;
 				taxonomy::point3::ptr previous;
 				for (std::vector<int>::const_iterator jt = indices.begin(); jt != indices.end(); ++jt) {
@@ -64,8 +64,8 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcIndexedPolyCurve* inst) {
 					}
 					previous = current;
 				}
-			} else if (segment->declaration().is(IfcSchema::IfcArcIndex::Class())) {
-				IfcSchema::IfcArcIndex* arc = (IfcSchema::IfcArcIndex*) segment;
+			} else if (segment->as<IfcSchema::IfcArcIndex>()) {
+				IfcSchema::IfcArcIndex* arc = segment->as<IfcSchema::IfcArcIndex>();
 				std::vector<int> indices = *arc;
 				if (indices.size() != 3) {
 					throw IfcParse::IfcException("Invalid IfcArcIndex encountered");
@@ -89,7 +89,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcIndexedPolyCurve* inst) {
 					Logger::Warning("Ignoring segment on", inst);
 				}
 			} else {
-				throw IfcParse::IfcException("Unexpected IfcIndexedPolyCurve segment of type " + segment->declaration().name());
+				throw IfcParse::IfcException("Unexpected IfcIndexedPolyCurve segment of type " + segment->as<IfcUtil::IfcBaseClass>()->declaration().name());
 			}
 		}
 	} else if (points.begin() < points.end()) {
diff --git a/src/ifcgeom/mapping/IfcTrimmedCurve.cpp b/src/ifcgeom/mapping/IfcTrimmedCurve.cpp
index aa1d286ca4..cc5d49596e 100644
--- a/src/ifcgeom/mapping/IfcTrimmedCurve.cpp
+++ b/src/ifcgeom/mapping/IfcTrimmedCurve.cpp
@@ -48,11 +48,11 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcTrimmedCurve* inst) {
 
 	for (auto it = trims1->begin(); it != trims1->end(); it ++) {
 		auto i = *it;
-		if ( i->declaration().is(IfcSchema::IfcCartesianPoint::Class()) ) {
+		if (i->as<IfcSchema::IfcCartesianPoint>()) {
 			pnts[sense_agreement] = taxonomy::cast<taxonomy::point3>(map(i));
 			has_pnts[sense_agreement] = true;
-		} else if ( i->declaration().is(IfcSchema::IfcParameterValue::Class()) ) {
-			const double value = *((IfcSchema::IfcParameterValue*)i);
+		} else if (i->as<IfcSchema::IfcParameterValue>()) {
+			const double value = *i->as<IfcSchema::IfcParameterValue>();
 			flts[sense_agreement] = value * parameterFactor;
 			has_flts[sense_agreement] = true;
 		}
@@ -60,11 +60,11 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcTrimmedCurve* inst) {
 
 	for (auto it = trims2->begin(); it != trims2->end(); it ++) {
 		auto i = *it;
-		if ( i->declaration().is(IfcSchema::IfcCartesianPoint::Class()) ) {
+		if (i->as<IfcSchema::IfcCartesianPoint>()) {
 			pnts[1 - sense_agreement] = taxonomy::cast<taxonomy::point3>(map(i));
 			has_pnts[1-sense_agreement] = true;
-		} else if ( i->declaration().is(IfcSchema::IfcParameterValue::Class()) ) {
-			const double value = *((IfcSchema::IfcParameterValue*)i);
+		} else if (i->as<IfcSchema::IfcParameterValue>()) {
+			const double value = *i->as<IfcSchema::IfcParameterValue>();
 			flts[1-sense_agreement] = value * parameterFactor;
 			has_flts[1-sense_agreement] = true;
 		}
diff --git a/src/ifcparse/aggregate_of_instance.h b/src/ifcparse/aggregate_of_instance.h
index b1645a6bb9..3ee8507426 100644
--- a/src/ifcparse/aggregate_of_instance.h
+++ b/src/ifcparse/aggregate_of_instance.h
@@ -90,10 +90,9 @@ class aggregate_of {
     template <class U>
     typename U::list::ptr as() {
         typename U::list::ptr result(new typename U::list);
-        const bool all = !U::Class().as_entity();
         for (it i = begin(); i != end(); ++i) {
-            if (all || (*i)->declaration().is(U::Class())) {
-                result->push((U*)*i);
+            if ((*i)->as<U>()) {
+                result->push(r->push((*i)->as<U>());
             }
         }
         return result;
@@ -150,13 +149,12 @@ class IFC_PARSE_API aggregate_of_aggregate_of_instance {
     template <class U>
     typename aggregate_of_aggregate_of<U>::ptr as() {
         typename aggregate_of_aggregate_of<U>::ptr result(new aggregate_of_aggregate_of<U>);
-        const bool all = !U::Class().as_entity();
         for (outer_it outer = begin(); outer != end(); ++outer) {
             const std::vector<IfcUtil::IfcBaseClass*>& from = *outer;
             typename std::vector<U*> to;
             for (inner_it inner = from.begin(); inner != from.end(); ++inner) {
-                if (all || (*inner)->declaration().is(U::Class())) {
-                    to.push_back((U*)*inner);
+                if ((*inner)->as<U>()) {
+                    to.push_back((*i)->as<U>());
                 }
             }
             result->push(to);