diff --git a/navi/main.py b/navi/main.py
index d299c9d..305c4b6 100644
--- a/navi/main.py
+++ b/navi/main.py
@@ -152,6 +152,17 @@
             pass
 
 
+from fastapi.responses import RedirectResponse
+
+
+@app.get("/sessions/{session_id}/files/{filename}", include_in_schema=False)
+async def legacy_session_file_redirect(session_id: str, filename: str, download: bool = False):
+    target = f"/api/sessions/{session_id}/files/{filename}"
+    if download:
+        target += "?download=1"
+    return RedirectResponse(url=target, status_code=301)
+
+
 @app.get("/", include_in_schema=False)
 async def index() -> FileResponse:
     return FileResponse(str(_base / "webclient" / "dist" / "index.html"), headers={"Cache-Control": "no-store"})
diff --git a/webclient/dist/content-viewers/stl.html b/webclient/dist/content-viewers/stl.html
index 7c39978..233fa99 100644
--- a/webclient/dist/content-viewers/stl.html
+++ b/webclient/dist/content-viewers/stl.html
@@ -63,63 +63,64 @@
                 + 'Try enabling hardware acceleration or a different browser.</p>'
                 + '</div>';
             console.error('WebGL init failed:', err);
-            throw err;
         }
 
-        const controls = new OrbitControls(camera, renderer.domElement);
-        controls.enableDamping = true;
-        controls.dampingFactor = 0.05;
-        controls.autoRotate = true;
-        controls.autoRotateSpeed = 1;
+        if (renderer) {
+            const controls = new OrbitControls(camera, renderer.domElement);
+            controls.enableDamping = true;
+            controls.dampingFactor = 0.05;
+            controls.autoRotate = true;
+            controls.autoRotateSpeed = 1;
 
-        // Lights
-        scene.add(new THREE.AmbientLight(0x404040, 2));
-        const dirLight = new THREE.DirectionalLight(0xffffff, 2);
-        dirLight.position.set(5, 10, 7);
-        scene.add(dirLight);
-        const backLight = new THREE.DirectionalLight(0x4444ff, 1);
-        backLight.position.set(-5, -5, -5);
-        scene.add(backLight);
+            // Lights
+            scene.add(new THREE.AmbientLight(0x404040, 2));
+            const dirLight = new THREE.DirectionalLight(0xffffff, 2);
+            dirLight.position.set(5, 10, 7);
+            scene.add(dirLight);
+            const backLight = new THREE.DirectionalLight(0x4444ff, 1);
+            backLight.position.set(-5, -5, -5);
+            scene.add(backLight);
 
-        // Load STL
-        const loader = new STLLoader();
-        loader.load(url, (geometry) => {
-            document.getElementById('loading').style.display = 'none';
+            // Load STL
+            const loader = new STLLoader();
+            loader.load(url, (geometry) => {
+                document.getElementById('loading').style.display = 'none';
 
-            geometry.computeBoundingSphere();
-            const center = geometry.boundingSphere.center;
-            const radius = geometry.boundingSphere.radius;
+                geometry.computeBoundingSphere();
+                const center = geometry.boundingSphere.center;
+                const radius = geometry.boundingSphere.radius;
 
-            const material = new THREE.MeshStandardMaterial({
-                color: 0xe0af68,
-                metalness: 0.12,
-                roughness: 0.55,
+                const material = new THREE.MeshStandardMaterial({
+                    color: 0xe0af68,
+                    metalness: 0.12,
+                    roughness: 0.55,
+                });
+                const mesh = new THREE.Mesh(geometry, material);
+                mesh.position.sub(center);
+                scene.add(mesh);
+
+                // Auto-scale camera
+                camera.position.setLength(radius * 3);
+                controls.target.set(0, 0, 0);
+                controls.update();
+            }, undefined, (err) => {
+                document.getElementById('loading').textContent = 'Failed to load model';
+                console.error(err);
             });
-            const mesh = new THREE.Mesh(geometry, material);
-            mesh.position.sub(center);
-            scene.add(mesh);
 
-            // Auto-scale camera
-            camera.position.setLength(radius * 3);
-            controls.target.set(0, 0, 0);
-            controls.update();
-        }, undefined, (err) => {
-            document.getElementById('loading').textContent = 'Failed to load model';
-            console.error(err);
-        });
+            function animate() {
+                requestAnimationFrame(animate);
+                controls.update();
+                renderer.render(scene, camera);
+            }
+            animate();
 
-        function animate() {
-            requestAnimationFrame(animate);
-            controls.update();
-            renderer.render(scene, camera);
+            addEventListener('resize', () => {
+                camera.aspect = innerWidth / innerHeight;
+                camera.updateProjectionMatrix();
+                renderer.setSize(innerWidth, innerHeight);
+            });
         }
-        animate();
-
-        addEventListener('resize', () => {
-            camera.aspect = innerWidth / innerHeight;
-            camera.updateProjectionMatrix();
-            renderer.setSize(innerWidth, innerHeight);
-        });
     </script>
 </body>
 </html>
diff --git a/webclient/public/content-viewers/stl.html b/webclient/public/content-viewers/stl.html
index 7c39978..233fa99 100644
--- a/webclient/public/content-viewers/stl.html
+++ b/webclient/public/content-viewers/stl.html
@@ -63,63 +63,64 @@
                 + 'Try enabling hardware acceleration or a different browser.</p>'
                 + '</div>';
             console.error('WebGL init failed:', err);
-            throw err;
         }
 
-        const controls = new OrbitControls(camera, renderer.domElement);
-        controls.enableDamping = true;
-        controls.dampingFactor = 0.05;
-        controls.autoRotate = true;
-        controls.autoRotateSpeed = 1;
+        if (renderer) {
+            const controls = new OrbitControls(camera, renderer.domElement);
+            controls.enableDamping = true;
+            controls.dampingFactor = 0.05;
+            controls.autoRotate = true;
+            controls.autoRotateSpeed = 1;
 
-        // Lights
-        scene.add(new THREE.AmbientLight(0x404040, 2));
-        const dirLight = new THREE.DirectionalLight(0xffffff, 2);
-        dirLight.position.set(5, 10, 7);
-        scene.add(dirLight);
-        const backLight = new THREE.DirectionalLight(0x4444ff, 1);
-        backLight.position.set(-5, -5, -5);
-        scene.add(backLight);
+            // Lights
+            scene.add(new THREE.AmbientLight(0x404040, 2));
+            const dirLight = new THREE.DirectionalLight(0xffffff, 2);
+            dirLight.position.set(5, 10, 7);
+            scene.add(dirLight);
+            const backLight = new THREE.DirectionalLight(0x4444ff, 1);
+            backLight.position.set(-5, -5, -5);
+            scene.add(backLight);
 
-        // Load STL
-        const loader = new STLLoader();
-        loader.load(url, (geometry) => {
-            document.getElementById('loading').style.display = 'none';
+            // Load STL
+            const loader = new STLLoader();
+            loader.load(url, (geometry) => {
+                document.getElementById('loading').style.display = 'none';
 
-            geometry.computeBoundingSphere();
-            const center = geometry.boundingSphere.center;
-            const radius = geometry.boundingSphere.radius;
+                geometry.computeBoundingSphere();
+                const center = geometry.boundingSphere.center;
+                const radius = geometry.boundingSphere.radius;
 
-            const material = new THREE.MeshStandardMaterial({
-                color: 0xe0af68,
-                metalness: 0.12,
-                roughness: 0.55,
+                const material = new THREE.MeshStandardMaterial({
+                    color: 0xe0af68,
+                    metalness: 0.12,
+                    roughness: 0.55,
+                });
+                const mesh = new THREE.Mesh(geometry, material);
+                mesh.position.sub(center);
+                scene.add(mesh);
+
+                // Auto-scale camera
+                camera.position.setLength(radius * 3);
+                controls.target.set(0, 0, 0);
+                controls.update();
+            }, undefined, (err) => {
+                document.getElementById('loading').textContent = 'Failed to load model';
+                console.error(err);
             });
-            const mesh = new THREE.Mesh(geometry, material);
-            mesh.position.sub(center);
-            scene.add(mesh);
 
-            // Auto-scale camera
-            camera.position.setLength(radius * 3);
-            controls.target.set(0, 0, 0);
-            controls.update();
-        }, undefined, (err) => {
-            document.getElementById('loading').textContent = 'Failed to load model';
-            console.error(err);
-        });
+            function animate() {
+                requestAnimationFrame(animate);
+                controls.update();
+                renderer.render(scene, camera);
+            }
+            animate();
 
-        function animate() {
-            requestAnimationFrame(animate);
-            controls.update();
-            renderer.render(scene, camera);
+            addEventListener('resize', () => {
+                camera.aspect = innerWidth / innerHeight;
+                camera.updateProjectionMatrix();
+                renderer.setSize(innerWidth, innerHeight);
+            });
         }
-        animate();
-
-        addEventListener('resize', () => {
-            camera.aspect = innerWidth / innerHeight;
-            camera.updateProjectionMatrix();
-            renderer.setSize(innerWidth, innerHeight);
-        });
     </script>
 </body>
 </html>