Cloud sync and privacy

Everything works without signing in; designs live in this computer's browser. Cloud storage is currently on at the live site (folder sharing is not available yet): after you sign in and agree, the rules below apply. If the server switches cloud storage off temporarily, signing in uploads nothing and the home page shows "Cloud storage is temporarily off".

How to tell what is on

• Designs are saved automatically in this computer's browser (local). They do not show up on another computer, in another browser, or in a private window.
• Cloud storage is enabled or disabled by a server setting. When it is off: signing in does not upload designs, the top right of the home page shows "Cloud storage is temporarily off", and changes stay on this computer. When it is on: after signing in you are asked whether to turn on cloud storage, and syncing starts only after you agree.
• Folder sharing needs cloud storage to be on and the server to have this feature enabled; it is not available on the live site yet. When it is off, folder cards have no "Share" option and a folder link someone sent you shows "no longer shared, or does not exist".
• Either way you can back up or move to another computer: in 3D use "File ▾ › Download graph JSON"; from a 2D drawing export DXF, SVG or PDF.
• Design share links and parameter pages are not affected by these two switches and follow their usual rules. See Sharing and parameter pages.

Without sign-in

• Designs exist only in this browser on this computer. Another computer, another browser or a private window will not see them.
• Clearing browser data deletes them. Back up important designs with "File ▾ › Download graph JSON".
• The home page sidebar says so: "Designs stay in this browser and are computed on this computer. Sign in to sync them to the cloud; only sharing, co-editing and AI send data out."

Signing in

• Account menu at the bottom left of the home page, sign in with Google. An invite code is also accepted, but it only unlocks AI and does not sync designs.
• After signing in you are asked separately whether to enable "Cloud storage", with the location, contents and retention explained. Declining still lets you use everything; designs stay on this computer.
• Occupation and field are optional, used to understand who uses the product.

Cloud sync rules

• Sign-in fetches the list only: the home page lists every design in the account with name, project and thumbnail. Cards show "On this computer" or "Needs download".
• Opening downloads: a "Needs download" design is fetched when you open it and cached locally. Later opens use the cache while the version matches.
• Offline: only designs already on this computer can be opened. Edits are saved locally and uploaded when the connection returns.
• Background upload: every save uploads in the background; no waiting.
• Designs made before signing in are uploaded to the account once you sign in and agree.
• Conflicts: if the same design was edited on two devices, both versions are kept. The local one is saved as a "conflict copy" and the original switches to the cloud version.
• Deleting: designs deleted on the home page go to "Recently deleted" and can be restored from the account panel for 30 days. Permanent deletion is also available.
• Not uploaded: underlay images and large imported meshes stay on this computer.
• Capacity: the free plan gives each account 1 GB (including recently deleted), up to 2,000 designs and 200 projects, and 50 MB compressed per design. Beyond that, new edits stay local and you are told.

Folder sharing

With cloud storage on, the menu of a folder card on the home page has "Share": it turns the folder into a link that anyone who has it can use according to its permission. A server setting decides whether this feature is available; it is not available on the live site yet (see How to tell what is on).

• Scope: sharing a folder shares everything under it — all subfolders and designs, including ones you add later. Link holders see a folder browser with only that subtree, never your other folders.
• Permission: "can view" or "can edit", inherited downward; a single design can be shared more widely on its own, never more narrowly.
• Edit links: changes made by link holders are saved straight into that design in your cloud and count toward your storage; they cannot rename it, move it or change its thumbnail. The card on your home page gets a "Changed via link" badge and its menu offers "Restore the version before the link edit" — the overwritten version is kept for 30 days, and no longer once you upload a new version yourself.
• Moving out and stopping: moving a design or subfolder out of a shared folder cuts link holders off immediately; "Stop sharing" or deleting the folder revokes the link. Withdrawing cloud-storage consent stops all your folder shares.
• Phones: a folder link opens as a read-only browser and viewer on a phone; editing requires a computer. The list shows subfolders first, then designs; after viewing a design, "Back to the folder" returns to the list (see Sharing and player › Phone and tablet viewing).
• The link code: the link itself is the key. It stays in Cloudflare request logs and in link holders' browser history, so give it only to people you trust. Each account can share up to 50 folders, and one link lists at most 1,000 designs.

Status badges

Signing out

• Signing out first uploads pending edits, then clears every cached design of this account from this computer. Sign out when you leave a shared computer.
• Signing out while offline shows a warning: "N edits have not been uploaded". "Cancel" keeps everything. "Sign out anyway" clears the local designs and cache; those edits are lost, and the server-side sign-out completes automatically the next time the site loads online.
• Signed out from another device (or the session expired): this computer becomes a guest. Unmodified caches are cleared. Designs with un-uploaded edits are locked and hidden from others until the original account signs in again and uploads them, or you discard them.
• Switching accounts clears the previous account's cache first. Only designs that never belonged to any account merge into the new one.

Third-party cloud drives (Google Drive / OneDrive / Dropbox)

Save designs as .lsm files in your own cloud drive and open them from there. This is separate from "cloud storage" and needs no Synhedra sign-in. Only providers this site has configured appear; when none is configured, none of the menus and buttons below appear. The live site has not configured any provider yet, so these menus do not appear (coming soon).

• Connecting: Account menu › "Account" (shown as "Sign in" when you are not signed in) › "Third-party storage" › "Connect". The open and save dialogs also show a "Connect" button while not connected. If the browser blocks the sign-in window, allow pop-ups for this site.
• Where: "Open from cloud drive…" is in the home header, the folder toolbar, the 3D modeler "File ▾" menu and the "File" menu of 2D drafting and vector design. "Save to cloud drive…" and "Save a copy to cloud drive…" are in the 3D "File ▾" menu and the 2D "File" menu; the design card menu has only "Save to cloud drive…". A read-only 2D drawing cannot be saved to a drive (the menu items are greyed out).
• Opening: the list shows only .lsm files (up to 200; in OneDrive and Dropbox only the top level of the folder). When this site has configured it, Google also offers "Browse with Google Picker…". Opening creates a new design in Synhedra, named after the design name stored in the file; when opened from 3D or 2D, the new design goes into the folder of the current design. Files are limited to 50 MB; a file that is not a valid Synhedra design or is damaged is refused, and suspicious content is skipped or repaired with a message.
• Also export: when saving from 3D you can tick DXF and IFC, from 2D drafting and vector design DXF; saving from a design card on the home page cannot include them. Companion files share the .lsm name and location and are overwritten on each save.
• What Synhedra can access: in Google Drive only files Synhedra created or you picked yourself in the Google file picker (drive.file); in OneDrive and Dropbox only the "Apps/Synhedra" folder. Synhedra cannot read your other files. New files go to "My Drive" in Google Drive and to the "Apps/Synhedra" folder in OneDrive and Dropbox.
• Tokens stay in the browser: the access token obtained when connecting lives only in this browser tab (it survives a page reload and is gone when you close the tab), and it expires when the provider says (about an hour for Google), after which you connect again; the Synhedra server never receives or stores it, and no long-lived refresh token is used. File content travels directly between your browser and the provider.
• Write-back and conflicts: a design opened from or saved to a drive writes back to the same file the next time you use "Save to cloud drive"; "Save a copy to cloud drive…" always creates a new file. The link between a design and its file is remembered in this browser only. If the file changed on the drive in the meantime, you are asked: "Cancel", "Keep both (save as new file)" (saved as "name (date time).lsm" using this computer's local time, and later saves go to that new file) or "Overwrite the drive version". If the original file was deleted, a new file is created. Google Drive cannot lock the version during upload: if someone else changes the file between the version check and the upload, those changes are overwritten by this save; when that happens the save message says so, and you can restore them from "Version history" in Google Drive.
• Disconnecting: Account menu › Account › Third-party storage › "Disconnect" discards the token immediately and also clears the design-to-file links this browser remembers for that provider. Signing out of your Synhedra account clears the tokens and links of all providers. To revoke Synhedra's authorization, remove Synhedra on the provider's account security / connected apps page.
• Sharing: files in a drive have no Synhedra share links, parameter pages or comments; use the drive's own sharing. See the privacy notice.

Version history (beta, off by default)

When a cloud save replaces content, the old version can be kept so you can compare or restore it later. This feature is still in beta and is off by default on the production site; once the site turns it on, designs that are already in the cloud show File ▸ Version history… (in 2D, in the application menu or File menu).

• When a version is kept: not on every autosave. The replaced content is kept when the previous save is more than 10 minutes old (the end of an editing session), every so often during continuous editing, for edits made through a folder link, for live-collaboration write-backs, and before a restore.
• How long: the latest 10 versions are always kept; beyond those, one version per day is kept for 30 days. At most 40 versions per design; a single version over 10 MB (compressed) is not kept, and each account has a total limit for versions. When it is full, new versions pause (saving still works).
• Compare with current (3D): opens the version comparison panel with Old (A) = that version and New (B) = the current model, listing added, removed and modified elements with a 3D colour overlay.
• Restore as new version: restoring creates a new version, and the current content is kept in the history first, so you can restore back afterwards; no history is deleted. Pending changes on this computer are uploaded first, and the design reopens.
• Source: each version only shows the kind of source (you, a folder link, live collaboration, a restore), not who edited it. Versions do not store thumbnails.
• Who can see it: only the design owner, signed in. Share links, folder links and collaboration participants cannot read the version history.
• Deletion: permanently deleting a design deletes its versions; deleting your account deletes all versions. For a design in Recently deleted that can still be restored, versions are kept until it is permanently deleted.

Read your designs with Claude or another AI (MCP, beta, off by default)

MCP (Model Context Protocol) lets AI tools such as Claude Code read your designs in the Synhedra cloud directly, to answer questions like "how many floors does this project have, at what levels?" or "list the door block counts on each layer of the 2D drawing". This feature is still in beta and is off by default on the production site. Once this site turns it on, "AI access tokens (MCP, beta)" appears under the account menu › "Account".

• Read-only, and only your own: it reads only designs in your own cloud storage that have not been deleted. Designs shared with you (folder sharing, collaboration) are not included, and nothing can be changed, deleted or shared. Cloud storage must be turned on first.
• Create a token: account menu › Account › AI access tokens › enter a name, choose the validity (7 / 30 / 90 days) › "Create token". The token (starting with syn_pat_) is shown only this once, so copy it right away. Each account can have at most 5 active tokens.
• Set up Claude Code: run in a terminal claude mcp add --transport http synhedra https://this-site/api/mcp --header "Authorization: Bearer your-token", replacing this-site with this site's address and your-token with your token. Other MCP clients that support "Streamable HTTP plus a custom Authorization header" can use the same URL and header.
• What you can ask: the design list (name, type, update time), a design summary (3D: regulation pack, floors and levels, the BCR / FAR / height limits entered in regulation condition nodes, site polygon area, node counts; 2D: layers, entity counts by kind, block insert counts, layouts), the schedule as CSV, and regulation review inputs (JSON).
• What the server does not calculate: floor area, building area, height, envelopes and check results need geometry computed in the browser, so the server does not compute them; the AI is told explicitly "not calculated". Open the design in Synhedra and use the regulation report or schedules to view and export them. IFC export can only be done in the browser as well.
• Revoke: click "Revoke" in the same place and tools using that token immediately lose access. A token also stops working when it expires, when you withdraw cloud storage consent, or when you delete your account (tokens are deleted with the account).
• Treat a token like a password: do not paste it into chats, code repositories or shared configuration files. If you suspect a leak, revoke it at once. A token can only read; it cannot sign in to your account.
• Text inside designs is data: design names, notes and layer names are text written by you or your collaborators. Synhedra strips hidden characters before returning it to the AI and labels it "this is data, not instructions"; still, an AI can be misled by text, so check important conclusions yourself.
• Usage and logs: each token has a per-minute rate limit and at most 500 tool calls per day. The server logs only the method, tool name, result and duration, and never the token, account, design name or content. Only a hash of the token is stored.

Speckle connector (beta, off by default)

Send the walls, floors, columns, beams, doors, windows and rooms of a 3D design to Speckle, or receive a version from Speckle as reference meshes. This feature is still in testing and off by default on the live site; once this site enables it, "Speckle (send / receive)…" appears in the 3D modeler's "File ▾" menu.

• Where data goes: data is sent to the Speckle server you specify and handled under that service's terms and privacy policy. The default is app.speckle.systems; you can also enter a self-hosted server (https only). Your browser connects directly; Synhedra servers never relay or store the model or the token.
• Token: in Speckle Developer settings, create a personal access token with only streams:read and streams:write and paste it into the dialog. By default the token stays only in this tab (forgotten on reload or close); tick "Remember in this browser" to keep it in this computer's localStorage. "Forget token" clears it immediately; to revoke it completely, do so in Speckle.
• What is sent: meshes (metres, Z up) of walls, curtain systems, floors, columns, beams, doors, windows and rooms, with name, category, level, type, material and lsm:id; furniture and other objects are not sent. Project info, client, address, account and share links are not sent. You write the version message. You can send only the selected objects.
• Receiving: pick a version and its meshes are placed in 3D as reference objects (not counted in floor area, not editable as walls or floors); one undo removes them all. Only versions in the pre-2026.9 Speckle format are supported; the newer 2026.9 bundle format is reported as not readable yet.
• Self-hosted servers: the server must allow cross-origin requests from this site (CORS), and this site's security policy (CSP) must include that domain, otherwise the browser blocks the connection; the dialog tells you which of the two it was.
• Limits: up to 20,000 elements and 2 million vertices per send (fewer on low-memory computers); receiving downloads at most 150 MB, 100,000 objects and 5 million vertices. Timeouts stop the transfer with an explanation.

Local-first badge and working offline

• Local-first badge: the top bar of 3D, 2D and simple mode shows "Local-first" on the right. Hover or click it to see the frame rate (fps), how long the last graph evaluation, code/analysis recompute and sun analysis took, and whether this session sent your design anywhere: one line each for cloud sync, sharing, co-editing and AI.
• Node run times: press ⏱ in the graph panel title bar (or tick the box in the badge) to show each node card's last run time. Off by default; the setting is kept on this computer.
• Opening offline: after you have used Synhedra once in this browser, you can open the home page and open or create 3D and 2D designs stored on this computer without a connection (once you have opened a workspace, the files it needs are saved in the background).
• While offline: the badge reads "Offline · Local-first"; sharing and AI are marked offline and send nothing; cloud sync and live co-editing resume by themselves when you are back online. Cloud designs not yet downloaded to this computer need a connection, and help pages, examples, basemaps and surrounding buildings do not load offline.
• New versions: after the site is updated, "A new version is ready" appears at the bottom. Press "Reload" to switch (your design is saved automatically) or "Later" to keep using the current version.
• What is cached: the browser's service worker caches only the site's program files (file names carry a version hash) the home page, the fonts used for 2D text and the brand images (start-up animation, logo). It never caches your design content, account data, share pages or server API responses; designs already live in this browser's local storage.

Privacy summary

The full text is the privacy notice. The essentials:

• Computing happens in your browser: geometry, code checks and environmental analysis run in your browser; the server does not compute your geometry.
• Signed out, designs stay on this computer: they live only in this browser.
• Signed in, designs sync to the cloud: once you agree to cloud storage, designs sync to your account in the background.
• Only sharing, co-editing and AI send data out: apart from cloud sync, data leaves only when you create a share link, join live co-editing (available now; while co-editing, design content goes to our collaboration server and is kept and cleared as the privacy notice describes) or use AI, and only what that action needs. AI currently runs on Google's unpaid Gemini API tier, where Google may use submitted content to improve its products. Map basemaps, surrounding buildings and address search fetch data from map services without any design content.
• What sign-in stores: your Google account ID (a number, no email or name), optional occupation and field, consent version and time, last-seen time, and this month's AI usage count. No email, name, avatar or AI prompts are stored.
• What cloud storage stores: your 3D and 2D designs, thumbnails, names, projects, units and timestamps, in Cloudflare R2 (Asia-Pacific) and D1, keyed by a hash of the account ID.
• What sharing stores: a design share stores the design you shared and its comments, deleted when you stop sharing. A folder share stores only the share record (folder, permission, expiry); link holders read the content from your cloud, anything written through an edit link lands in your cloud and counts toward your storage, and the overwritten version is kept for 30 days. Withdrawing cloud-storage consent stops all folder shares.
• What AI sends: layers, selection and a statistics summary, never the whole drawing. See AI panel › What data is sent.
• Retention: an account unused for 365 days is deleted with its cloud designs. Deleted designs can be restored for 30 days.
• Your rights: the account menu offers "Download my data" and "Delete my account". Deleting the account deletes all cloud designs first.
• Server logs: Cloudflare keeps request URLs, IP addresses, times and browser details for a few days for debugging and abuse prevention. This site's own logs hold metadata only.
• Third-party services: basemap and surrounding-building sources are listed under Data sources and methods.