diff --git a/src/ifcgeom/taxonomy.cpp b/src/ifcgeom/taxonomy.cpp
index 7d509db8cb..2ce115dfd1 100644
--- a/src/ifcgeom/taxonomy.cpp
+++ b/src/ifcgeom/taxonomy.cpp
@@ -543,8 +543,8 @@ piecewise_function::const_ptr offset_function::get_offset() const { return offse
 ifcopenshell::geometry::taxonomy::collection::ptr ifcopenshell::geometry::flatten(const taxonomy::collection::ptr& deep) {
 	auto flat = make<taxonomy::collection>();
 	ifcopenshell::geometry::visit<taxonomy::collection>(deep, [&flat](taxonomy::ptr i) {
-		flat->children.push_back(taxonomy::cast<taxonomy::geom_item>(clone(i)));
-		});
+		flat->children.push_back(std::static_pointer_cast<taxonomy::geom_item>(clone(i)));
+	});
 	return flat;
 }
 
diff --git a/src/ifcgeom/taxonomy.h b/src/ifcgeom/taxonomy.h
index ab8a222aee..5d70d4490c 100644
--- a/src/ifcgeom/taxonomy.h
+++ b/src/ifcgeom/taxonomy.h
@@ -1622,25 +1622,19 @@ typedef item const* ptr;
 			for (auto& i : deep->children) {
 				// @todo Sad... now that we have templated collection members,
 				// we can't generally use collection_base anymore as a cast target.
-				if (auto s = taxonomy::dcast<taxonomy::collection>(i)) {
+				if (auto s = std::dynamic_pointer_cast<taxonomy::collection>(i)) {
 					visit<taxonomy::collection>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::loop>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::loop>(i)) {
 					visit<taxonomy::loop>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::face>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::face>(i)) {
 					visit<taxonomy::face>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::shell>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::shell>(i)) {
 					visit<taxonomy::shell>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::solid>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::solid>(i)) {
 					visit<taxonomy::solid>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::loft>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::loft>(i)) {
 					visit<taxonomy::loft>(s, fn);
-				}
-				else if (auto s = taxonomy::dcast<taxonomy::boolean_result>(i)) {
+				} else if (auto s = std::dynamic_pointer_cast<taxonomy::boolean_result>(i)) {
 					visit<taxonomy::boolean_result>(s, fn);
 				}
 				else {