diff --git a/src/ifcviewer/GeometryStreamer.cpp b/src/ifcviewer/GeometryStreamer.cpp
index 39698c84e6..437209c909 100644
--- a/src/ifcviewer/GeometryStreamer.cpp
+++ b/src/ifcviewer/GeometryStreamer.cpp
@@ -94,7 +94,7 @@ std::vector<ElementInfo> GeometryStreamer::drainElements() {
 
 void GeometryStreamer::run(const std::string& path, int num_threads) {
     try {
-        ifc_file_ = std::make_unique<IfcParse::IfcFile>(path);
+        ifc_file_ = std::make_unique<ifcopenshell::file>(path);
     } catch (const std::exception& e) {
         emit errorOccurred(QString("Failed to parse IFC file: %1").arg(e.what()));
         return;
@@ -112,7 +112,7 @@ void GeometryStreamer::run(const std::string& path, int num_threads) {
         auto kernel = ifcopenshell::geometry::kernels::construct(
             ifc_file_.get(), geometry_library, settings);
         iterator = std::make_unique<IfcGeom::Iterator>(
-            std::move(kernel), settings, ifc_file_.get(), std::vector<IfcGeom::filter_t>(), num_threads);
+            std::move(kernel), settings, ifc_file_.get(), std::vector<ifcopenshell::geometry::filter_t>(), num_threads);
     } catch (const std::exception& e) {
         emit errorOccurred(QString("Failed to create geometry iterator: %1").arg(e.what()));
         return;
diff --git a/src/ifcviewer/GeometryStreamer.h b/src/ifcviewer/GeometryStreamer.h
index 06b6364a24..abd087463c 100644
--- a/src/ifcviewer/GeometryStreamer.h
+++ b/src/ifcviewer/GeometryStreamer.h
@@ -31,7 +31,7 @@
 #include <mutex>
 #include <deque>
 
-#include "../ifcparse/IfcFile.h"
+#include "../ifcparse/file.h"
 #include "../ifcgeom/Iterator.h"
 
 #include "ViewportWindow.h"
@@ -57,7 +57,7 @@ public:
     bool isRunning() const { return running_.load(); }
     int progress() const { return progress_.load(); }
 
-    IfcParse::IfcFile* ifcFile() const { return ifc_file_.get(); }
+    ifcopenshell::file* ifcFile() const { return ifc_file_.get(); }
 
     // Thread-safe access to discovered elements
     std::vector<ElementInfo> drainElements();
@@ -73,7 +73,7 @@ private:
 
     UploadChunk convertElement(const IfcGeom::TriangulationElement* elem, uint32_t object_id);
 
-    std::unique_ptr<IfcParse::IfcFile> ifc_file_;
+    std::unique_ptr<ifcopenshell::file> ifc_file_;
     std::unique_ptr<QThread> worker_thread_;
     std::atomic<bool> running_{false};
     std::atomic<bool> cancel_requested_{false};
diff --git a/src/ifcviewer/MainWindow.cpp b/src/ifcviewer/MainWindow.cpp
index 1f32ce0877..6eede35353 100644
--- a/src/ifcviewer/MainWindow.cpp
+++ b/src/ifcviewer/MainWindow.cpp
@@ -244,23 +244,23 @@ void MainWindow::populateProperties(uint32_t object_id) {
     auto* file = streamer_->ifcFile();
     if (!file) return;
 
-    auto* product = file->instance_by_id(info.ifc_id);
+    auto product = file->instance_by_id(info.ifc_id);
     if (!product) return;
 
     // Show all direct attributes
-    auto& decl = product->declaration();
+    auto& decl = product.declaration();
     if (auto* entity = decl.as_entity()) {
         for (size_t i = 0; i < entity->attribute_count(); ++i) {
             auto* attr = entity->attribute_by_index(i);
             try {
-                auto val = product->get_attribute_value(i);
+                auto val = product.get_attribute_value(i);
                 if (!val.isNull()) {
                     std::string str_val;
                     try {
                         str_val = static_cast<std::string>(val);
                     } catch (...) {
                         // Not a string-convertible attribute (entity ref, aggregate, etc.)
-                        str_val = "<" + std::string(IfcUtil::ArgumentTypeToString(val.type())) + ">";
+                        str_val = "<" + std::string(ifcopenshell::argument_type_to_string(val.type())) + ">";
                     }
                     addRow(QString::fromStdString(attr->name()), QString::fromStdString(str_val));
                 }