Blend Online Docs

1Installation

In Blender, open Edit > Preferences > Get Extensions.
Open the drop-down at the top right and choose Install from Disk, then pick the zip. You can also drag the zip into Blender.
Open Edit > Preferences > System > Network and turn on Allow Online Access. The add-on can't connect without it, and tells you so.

Everyone in a session needs the add-on installed, so send the zip to the people you work with. The 2 Users license covers you and one other person, the 8 Users license you and up to seven others. Both are the same add-on, and a session holds up to 8 people.

Different Blender versions can work together: 4.5 and 5.2 are tested connected to each other.

3Where to find it

The Blend Online window floats in the largest 3D Viewport of every workspace. Drag its title to move it (it docks left or right), drag the corner to resize it, or collapse it to a small pill with everyone's avatars and an unread badge. Clicks on the window never reach your scene.
The top bar button is in every workspace, also those without a 3D Viewport. Its popover shows the session, people, markings and a message field, and shows or hides the window.
The sidebar tab (N panel) is optional. Turn it on with Sidebar Tab in the preferences.

The window has five tabs: Chat, People, Voice, Marks and Session.

4Hosting a session

Hosting shares your current scene. Click Host a Session in the Session tab. The dialog has these settings:

Setting	What it does
Port	The port used on your computer (default 7777).
Password	Optional. Everyone who joins must enter it.
Your Name	The name others see.
Allow Internet Joins	Creates an invite code so people anywhere can join over the internet. No server or router setup is needed.

Windows may ask you to allow Blender through the firewall. End Session in the Session tab ends it for everyone. Opening another file or disabling the add-on also ends the session cleanly.

5Joining a session

With an invite code on your clipboard, the Session tab shows Join with the copied invite code. Otherwise click Join a Session and choose:

Invite Code: paste the code the host sent you. It starts with BO-.
Address: the host's IP address and port on your own network, or the address of a relay server.

The shared scene opens as a new scene in your file. Your other scenes are not changed. Leave Session in the Session tab disconnects you. If the host leaves, the session ends for everyone with a clear message.

6When it doesn't connect

With an invite code, the two computers find each other by themselves and connect directly. This works through most routers, including double NAT. If it takes long, try these in order:

Reply code. After a while the person joining is offered Copy Reply Code. Send it to the host, who clicks Paste Reply in the People tab.
Same network? Use Address with the host's local address and port. The hosting dialog shows it.
Relay server or VPN. Direct connections fail when both sides are behind a strict (symmetric) NAT, which is common on mobile networks. Run the relay server on any small server, or use a VPN such as Tailscale and join by address.

7What is shared

What	Details
Objects	Meshes, curves, text, empties, lights and cameras: add, delete, duplicate, rename, parent, transforms, visibility, collection.
Meshes	Geometry and UVs. Shared after each operation in Edit Mode, and from Sculpt Mode (not with dynamic topology).
Curves, text	Bezier, NURBS, poly and text objects with their settings. Changes from others wait while you edit the same curve.
Materials	Settings and whole node trees: color ramps, curve mappings, shader node groups, node layout.
Textures	Image files are sent in the background and packed into the receiver's file. Up to 64 MB per file; you get a message about larger ones.
Modifiers	Every modifier type with its settings, including Geometry Nodes inputs.
Geometry Nodes	Groups with nodes, links, values, zones and layout. Concurrent edits are merged node by node.
Constraints	Settings and targets. The Armature constraint's target list and bone-only types are not shared.
Collections	The nested tree, with visibility flags and color tags.
Animation	Keys, interpolation, easing, F-Curve modifiers on objects, lights, cameras and curves. Timeline markers.
Scene	World with its nodes, render engine, resolution, FPS, film, motion blur, simplify, frame range, units, color management, samples, active camera.

Not shared yet

Armatures and poses, Grease Pencil, metaballs, surfaces, volumes and other object types
Shape keys. Meshes with shape keys are shared when their user leaves Edit Mode.
NLA strips and drivers
Animation of materials, worlds and node trees
Movies, image sequences, UDIM tiles, and unsaved texture painting (shared once the image is saved)

Good to know

Same object at the same time: the last change wins. When two people edit one mesh in Edit, Sculpt or Paint Mode, both get a warning and an "is editing this too" label, and only the last version survives. Agree who takes what.
Very large meshes: a mesh that takes too long to read (around 800,000 vertices) is shared when its user leaves the mode, not after each operation. A single mesh of more than about 55 MB of encoded data is not shared, and you get an error line.
Nothing is applied or scanned while a render or bake runs, so renders are not disturbed.

8People and roles

The People tab shows everyone and what they work on.

Go to jumps to their view once.
Follow keeps your view on theirs, including their timeline frame. Moving your view stops following.
··· (host only) has Make viewer and Remove.

In the 3D Viewport, each person's selection is a colored box with their name, and a marker shows where they are looking.

Host options

New people join as viewers: viewers can look, chat, talk and mark, but can't change the scene.
Ask before letting people in: each person waits until you click Let in or Deny.

10Voice chat

Open the Voice tab and click Join Voice Chat. The microphone opens only then. Use headphones, otherwise the others hear themselves through your microphone.

Control	What it does
Microphone	Mutes you.
Voices	Turns everyone's voice off for you.
Talk	When I speak sends your voice when the meter passes the white line. Push to talk sends it while you hold `Mouse Button 4`.
Sensitivity	Lower it if noise gets sent.
Voice volume	How loud the others are.
Speaker icon	Mutes one person, only for you.

Pick devices in the preferences (Microphone, Speakers).

Voice chat runs on Windows and Linux (PulseAudio, PipeWire or ALSA). It is not available on macOS: Blender has no microphone permission there, and macOS ends apps that open the microphone without one.

11Markings and pings

Tool	What it does
Draw	Drag with the left mouse button to draw on the scene. `Ctrl`+`Z` removes your last line, right-click or `Esc` stops drawing.
Note	Pin a note to a spot.
Mark	Put corner brackets and a label on an object.
Ping	A temporary signal at a spot. `Ctrl`+`Alt`+`P` pings the point under the mouse.

Markings stay until they are removed, in their author's color, and people who join later see them too. Use Shown to hide them, Clear Mine or Clear All to remove them.

A drawing around an object in the 3D Viewport

13Preferences

Edit > Preferences > Add-ons > Blend Online

Setting	What it does
Your Name	The name others see. Empty uses your system user name.
Your Colour	Your color for selections and chat. The server picks another one if it is taken.
Host Port	The port used when you host.
Blend Online Window	Shows the floating window.
Sidebar Tab	Also shows Blend Online in the N panel.
Session Bar	Shows everyone's avatar at the top of the viewport.
Chat in Viewport	Shows new messages briefly at the bottom of the viewport. Message Time sets how long.
Chat Sound	Plays a short tone when a message arrives.
Connect Automatically	With an invite code, the person joining needs no reply code. See Network and privacy. Turn off to always exchange reply codes by hand.
Ask Before Letting People In	When you host, each person waits until you let them in.
Talk, Sensitivity, Volume	The defaults of the Voice tab.
Microphone, Speakers	Which audio devices voice chat uses.
Updates per Second	How often your changes are sent. Higher is smoother but uses more bandwidth.

Change the shortcuts in Preferences > Keymap: Ping (3D View) and Push to Talk (Window).

14Relay server

A relay is the same session server without Blender. Everyone connects out to it, so nobody needs direct connections. Use it when direct connections fail.

In the add-on preferences, click Export Relay Server Script. It saves blend_online_server.py.
Run it on a machine everyone can reach, with Python 3.8 or newer and nothing else:
python3 blend_online_server.py --port 7777 --password YOUR_PASSWORD
Everyone clicks Join a Session, chooses Address, and enters the server's address, port and password.

The first person to join shares their current scene. People who join later receive it.

Address and relay connections are not encrypted. The password only controls who can join. Use a VPN for confidential work on those. Invite code connections are encrypted.

15Network and privacy

Your scene goes directly from computer to computer. It is not stored on any server of ours: there are none. To find each other over the internet, invite code connections use public services:

STUN servers tell each computer its public address.
ntfy servers (ntfy.sh, ntfy.envs.net) pass the joiner's reply code to the host, encrypted. They see an encrypted message and the two IP addresses.
The public BitTorrent DHT is a second way to find each other. Only your public address is shared, under a key only invite holders know.

Turn Connect Automatically off to stop using ntfy and the DHT, for example on networks where BitTorrent traffic is not allowed. You then exchange reply codes by hand. Everyone with your invite code can join, so send it only to people you want in the session.

16Troubleshooting

"Online access is off"

Turn on Allow Online Access in Edit > Preferences > System > Network.

Joining takes long or never connects

Follow When it doesn't connect. Check that Windows allows Blender through the firewall.

Someone can't join: version message

Everyone needs a compatible version of the add-on. Update to the same version.

"No sound from your microphone"

Check Windows Settings > Privacy > Microphone (desktop apps), or choose another microphone in the preferences.

The others hear an echo

Use headphones. Without them, your microphone picks up their voices from your speakers.

Noise opens my microphone

Set Microphone Sensitivity lower, or use Push to talk.

A change didn't arrive

Check What is shared. A viewer's changes are put back, and changes from others wait while a tool is running.

I can't find the window

It lives in the largest 3D Viewport of each workspace. Use the Blend Online button in the top bar to show it.

Blend Online DocsVersion 0.9.1 · Blender 4.2 and newer