diff --git a/frontend/dcViewer.js b/frontend/dcViewer.js
index 37acfe3..8420eba 100644
--- a/frontend/dcViewer.js
+++ b/frontend/dcViewer.js
@@ -447,9 +447,10 @@ const configureCameraControl = () => {
   if (!control) return;
   activeZoomSpeed = normalizeZoomSpeed(activeZoomSpeed);
   configureCameraPanMap(control);
-  control.followPointer = true;
+  // Keep wheel dolly speed independent from whether the pointer is over model geometry.
+  control.followPointer = false;
   control.doublePickFlyTo = false;
-  control.smartPivot = true;
+  control.smartPivot = false;
   control.zoomOnMouseWheel = true;
   control.keyboardDollyRate = CAMERA_CONTROL_SETTINGS.keyboardDollyRate;
   control.mouseWheelDollyRate = activeZoomSpeed;
@@ -684,6 +685,8 @@ let nodeDCLogoutHandling = false;
 let nodeDCLoginHandling = false;
 let nodeDCSessionWatchTimer = null;
 let nodeDCSessionWatchInFlight = false;
+let nodeDCLoginSyncPrimed = false;
+let nodeDCLoginSyncEventId = "";
 
 const handleNodeDCSessionLogout = async () => {
   if (nodeDCLogoutHandling) return;
@@ -844,9 +847,24 @@ const scheduleShareSessionPromotion = (shareToken) => {
   document.body.appendChild(iframe);
 };
 
+const getLoginSyncEventId = (sessionPayload) => (
+  typeof sessionPayload?.loginSyncEventId === "string" ? sessionPayload.loginSyncEventId : ""
+);
+
 const applyLiveSessionPayload = async (sessionPayload, { reason = "watch" } = {}) => {
   const wasAuthenticated = runtimeSessionInfo.authenticated === true;
   const isAuthenticated = sessionPayload?.authenticated === true;
+  const loginSyncEventId = getLoginSyncEventId(sessionPayload);
+  const hasNewLoginSyncEvent =
+    nodeDCLoginSyncPrimed &&
+    !isAuthenticated &&
+    !!loginSyncEventId &&
+    loginSyncEventId !== nodeDCLoginSyncEventId;
+
+  nodeDCLoginSyncPrimed = true;
+  if (loginSyncEventId) {
+    nodeDCLoginSyncEventId = loginSyncEventId;
+  }
 
   runtimeSessionInfo = {
     ...runtimeSessionInfo,
@@ -861,6 +879,10 @@ const applyLiveSessionPayload = async (sessionPayload, { reason = "watch" } = {}
       await handleNodeDCSessionLogout();
       return;
     }
+    if (hasNewLoginSyncEvent) {
+      handleNodeDCSessionLogin();
+      return;
+    }
     const shareToken = getShareTokenFromPath();
     if (shareToken && viewerMode === "guest") {
       scheduleShareSessionPromotion(shareToken);
diff --git a/server/index.js b/server/index.js
index 382042d..ee7d4d5 100644
--- a/server/index.js
+++ b/server/index.js
@@ -56,6 +56,7 @@ const BIM_SESSION_COOKIE = process.env.NODEDC_BIM_SESSION_COOKIE || "nodedc_bim_
 const BIM_HANDOFF_COOKIE = process.env.NODEDC_BIM_HANDOFF_COOKIE || "nodedc_bim_handoff";
 const BIM_SESSION_TTL_MS = Number(process.env.NODEDC_BIM_SESSION_TTL_MS || 12 * 60 * 60 * 1000);
 const BIM_HANDOFF_TTL_SECONDS = Number(process.env.NODEDC_BIM_HANDOFF_TTL_SECONDS || 60);
+const BIM_LOGIN_SYNC_TTL_MS = Number(process.env.NODEDC_BIM_LOGIN_SYNC_TTL_MS || 60 * 1000);
 const BIM_COOKIE_SECURE = parseBooleanEnv(process.env.NODEDC_BIM_COOKIE_SECURE, false);
 const BIM_COOKIE_SAMESITE = process.env.NODEDC_BIM_COOKIE_SAMESITE || (BIM_COOKIE_SECURE ? "None" : "Lax");
 const SHARE_AUTH_GUEST_PARAM = "ndc_bim_guest";
@@ -64,6 +65,7 @@ const CORS_ALLOWED_ORIGINS = String(process.env.NODEDC_BIM_ALLOWED_ORIGINS || ""
     .map((origin) => origin.trim())
     .filter(Boolean);
 const bimSessions = new Map();
+let latestBimLoginSyncEvent = null;
 
 const MIME_TYPES = {
     ".html": "text/html",
@@ -721,6 +723,27 @@ const parseJSONBody = async (req) => {
 
 const randomBase64Url = (bytes = 24) => crypto.randomBytes(bytes).toString("base64url");
 
+const markBimLoginSyncEvent = () => {
+    const ttlMs = Number.isFinite(BIM_LOGIN_SYNC_TTL_MS) ? Math.max(1000, BIM_LOGIN_SYNC_TTL_MS) : 60 * 1000;
+    latestBimLoginSyncEvent = {
+        id: randomBase64Url(16),
+        createdAt: nowIso(),
+        expiresAt: Date.now() + ttlMs
+    };
+    return latestBimLoginSyncEvent;
+};
+
+const getActiveBimLoginSyncEvent = () => {
+    if (!latestBimLoginSyncEvent) {
+        return null;
+    }
+    if (latestBimLoginSyncEvent.expiresAt <= Date.now()) {
+        latestBimLoginSyncEvent = null;
+        return null;
+    }
+    return latestBimLoginSyncEvent;
+};
+
 const sanitizeReturnTo = (value, fallback = "/") => {
     if (typeof value !== "string" || !value.startsWith("/") || value.startsWith("//")) {
         return fallback;
@@ -1749,16 +1772,30 @@ const handleGetUploadVersions = async (req, res, searchParams) => {
 
 const handleAuthSession = async (req, res) => {
     const session = await getValidatedBimSession(req, res);
+    const loginSyncEvent = getActiveBimLoginSyncEvent();
+    res.setHeader("Cache-Control", "no-store");
     sendJSON(res, 200, {
         ok: true,
         authRequired: BIM_AUTH_REQUIRED,
         authenticated: !!session,
         canShare: !BIM_AUTH_REQUIRED || !!session,
         user: session?.user || null,
+        loginSyncEventId: loginSyncEvent?.id || null,
+        loginSyncEventCreatedAt: loginSyncEvent?.createdAt || null,
         loginUrl: session ? null : buildLauncherLoginUrl(req, "/")
     });
 };
 
+const handleLoginSync = (res) => {
+    const event = markBimLoginSyncEvent();
+    setCors(res);
+    res.statusCode = 200;
+    res.setHeader("Content-Type", "text/plain; charset=utf-8");
+    res.setHeader("Cache-Control", "no-store");
+    res.setHeader("X-NODEDC-Session-Event", event.id);
+    res.end("ok");
+};
+
 const handleLauncherHandoff = async (req, res, url) => {
     const token = url.searchParams.get("token") || "";
     const nextPath = sanitizeReturnTo(url.searchParams.get("next_path") || url.searchParams.get("returnTo") || "/");
@@ -3435,6 +3472,10 @@ const requestHandler = async (req, res) => {
         return handleSharePromoted(res, url);
     }
 
+    if (req.method === "GET" && url.pathname === "/auth/login-sync") {
+        return handleLoginSync(res);
+    }
+
     if (req.method === "GET" && url.pathname === "/auth/logout") {
         return handleLogout(req, res);
     }