Multi-User Editing with Aximmetry

Introduction

This document outlines the workflow for integrating Unreal Engine's Multi-User Editing functionality with Aximmetry.
With this setup, scene changes made on one or more Unreal Engine workstations appear in Aximmetry immediately, even when several people are editing at once.

Prerequisites

To deploy the Multi-User Edit workflow successfully, ensure your environment meets the following baseline requirements:

• Multiple Workstations: Multi-User Editing requires at least two workstations: one running Unreal Editor and one running Aximmetry. For Aximmetry Multi-Machine setups, you need at least three workstations: one running Unreal and two running Aximmetry in a Multi-Machine setup.
  NOTE: For ease of description, this document details the setup using the minimum number of workstations for both workflows. The setup steps and underlying mechanics remain identical when more Unreal or Aximmetry machines participate in Multi-User Editing.

• Render Component Licenses: At least one AX Scene Editor component is required to host and actively modify the scene (on the Unreal Editor machine(s)). The additional components (on the Aximmetry machines) can be either AX Scene Editors or AX Scene Render Nodes.

• Version Parity: Every machine in the setup must run the exact same combination of Aximmetry and Render Component versions.
  NOTE: Full Multi-User Editing support in Editor Data mode requires Aximmetry 2025.3.0 (or newer), paired with the corresponding Unreal Engine 5.6.1 (or newer) Render Component.

• Network Infrastructure: All machines must reside on the same Local Area Network (LAN), preferably connected by wire to maximize stability.

• File Synchronization Mechanism: You need a system for copying persisted project assets between machines. Any standard version control system (for example, Git or SVN) or file-sharing workflow can do the job, but our recommendation is the free and open-source FreeFileSync.

Single Aximmetry Machine Workflow

This section details the Multi-User Edit workflow using a single Aximmetry machine paired with an Unreal Editor machine.

In this configuration, one machine runs Aximmetry with the Unreal scene loaded, while the second machine runs the Unreal Editor.
As scene modifications are made on the Unreal Editor machine, the changes propagate across the network and update in real time on the Aximmetry machine.

Unreal Setup

Setting up the Multi-User Edit workflow is described in Unreal's Getting Started with Multi-User Editing documentation.

Follow steps 1 through 4 of Unreal's documentation to activate the Multi-User Editing plugin and start a Multi-User Edit server and session on the Unreal workstation.

Note the Server and Session name. These will be referred to as [Server] and [Session] in the next step.

As mentioned in "9 - On Your Own," the project can be set up to automatically connect to a default session on a default server.
We will use this method to connect the Unreal scene running in Aximmetry to AX Scene Editor.

Open the project in the editor and change the following settings in Project Settings > Plugins > Multi-User Editing:
Auto Connect = true
Default Server URL = [Server]
Default Session Name = [Session]

NOTE: [Server] and [Session] are placeholders: replace them with the server and session names you noted in the previous step, without the brackets.

NOTE: You might have to use the Set as Default button to apply the settings due to a bug in Unreal Editor (5.6).
We recommend restarting the editor and checking that the settings were applied successfully.

IMPORTANT: The server must be started on the Unreal Editor machine before the Aximmetry machines can auto-connect to the session. You can do this in the Multi-User Browser: 

Once the server is started, a session with the given Default Session name will automatically start (because we enabled Auto Connect).

Project Folder Setup

You must copy the Unreal project folder (with the Project Settings already configured as described above) to both workstations.

IMPORTANT: Make sure the project folder's content is identical on all machines when the Multi-User Edit session is started. You can use FreeFileSync for this purpose: see below. (Or the file sync system of your choice (Git, SVN, etc.)).

Aximmetry Setup

On the Aximmetry machine, load the synced Unreal scene into Aximmetry in Editor Data mode.

NOTE: Aximmetry can connect to an Unreal scene in three different modes. To learn more, see the following document:
Interactive Editing with Live Sync

In Editor Data mode, the Unreal scene can connect to Multi-User Edit sessions without the need to run AX Scene Editor.
NOTE: This is why AX Scene Render Node is sufficient on the Aximmetry machine for this workflow.

Because we turned on Auto Connect in the Project Settings, the Unreal scene automatically connects to the session (if the names are correct and the server has started) when it is loaded into Aximmetry. You should see your Aximmetry machine connect to the Multi-User Edit session in the Multi-User Browser once the compound (with the Unreal scene loaded into it in Editor Data mode) is running:

Now, when you edit the scene on the Unreal Editor machine, the changes appear live (immediately) in Aximmetry on the Aximmetry machine.

Persisting Changes

As the 7 - Persist Session Changes section of Unreal's documentation explains, to keep the changes made during the session, you have to Persist them (it's under Revision Control in the bottom right corner of the Editor):

IMPORTANT: NEVER save changes locally on the Unreal Editor machine during a Multi-User Edit session, as asset desynchronization between the machines will disrupt the whole configuration. ALWAYS use Persist!
A standard save alters your local files directly and bypasses the multi-user server, which immediately breaks the live synchronization between the machines. Using Persist safely commits the shared session's changes to disk on the Unreal Editor machine without disrupting the active connection.
NOTE: If you save accidentally, or your machines desync during the session, follow the troubleshooting instructions below.

Synchronizing Workstations

Once you have made all the modifications you wanted and persisted them all, stop the Multi-User Edit session: on the Aximmetry machine stop the running Aximmetry compound, on the Unreal Editor machine stop the session in the Multi-User Browser. 
This step is necessary to avoid errors during the synchronization.

Persisting saves the modifications to the Unreal Editor machine only.
To transfer the modified project files onto the Aximmetry machine, you need a file synchronization system.

You can use any standard version control system (for example, Git or SVN) or file-sharing workflow, but we recommend FreeFileSync for this workflow. You can learn how to set it up below.

Multi-Machine Aximmetry Workflow

This section details the Multi-User Edit workflow using a Multi-Machine Aximmetry setup paired with an Unreal Editor machine.

In this configuration, the Unreal scene is loaded into a Multi-Machine Aximmetry setup: the control machine runs Aximmetry Composer, and the remote render machines run Aximmetry Renderer. A separate machine runs the Unreal Editor. As scene modifications are made on the Unreal Editor machine, the changes propagate across the network and update in real time on every machine in the Aximmetry setup.

Unreal Setup

The Unreal setup is the same as it was for the single-machine workflow detailed above.

Aximmetry Multi-Machine Setup

To set up your Aximmetry machines in a Multi-Machine environment, follow our documentation: Introduction to Multi-Machine Environment.

After the remote machines have connected to the control machine, load the Unreal project into your Aximmetry compound in Editor Data mode, just as before.

NOTE: As mentioned above, AX Scene Render Node is sufficient as a render component on both the control and remote machines.

Project Folder Setup: Unified Path Architecture

Aximmetry's Multi-Machine setup requires a single, shared Projects root folder for each connected workstation, while Unreal's Multi-User Editing requires all workstations to have a local copy of the Unreal scene's project folder.

For this reason, you have to place the local Unreal project folder at the exact same path on all machines, for example C:\YourUnrealProject, since all computers usually have a C: drive.
This way, when the Aximmetry compound loads the referenced Unreal project, it is available at the same place on all the Aximmetry machines.

NOTE: Example with the Complex stock Unreal scene.

Ignoring the Saved Folder

To run the synchronization without errors while AX Scene Editor is running on the Unreal Editor machine, the Saved folder of the project folder has to be excluded from the sync.
NOTE: This folder is a temporary working subfolder that Unreal Engine rebuilds automatically, so excluding it does not affect the current workflow.
NOTE: To do this in FreeFileSync, use the Filter function and exclude the Saved folder.

IMPORTANT: After you finish working in Multi-User mode and you want to cook the Unreal scene and sync it to all machines, you should no longer exclude the Saved folder, as it contains the cooked data.

Multi-Machine Multi-User Edit Workflow Steps

This workflow is much more complex than the single-machine one, which means that besides the setup steps themselves, their exact order is crucial for correct functionality.
Here you can find an ordered list summarizing all the steps:

1. Start the Unreal scene in AX Scene Editor on your Unreal Editor machine. Configure the scene's Project Settings for Multi-User Editing as detailed above.
2. Set up the exclusion rule for the Saved folder in your file synchronization system. In FreeFileSync:  Filter > Exclude function.
3. Launch the Multi-User Edit session on the Unreal Editor machine in AX Scene Editor, as shown above in the Unreal Setup section.
4. Synchronize the Unreal project folder from the Unreal Editor machine to the Aximmetry machines (both control and remote). You should not have to close AX Scene Editor during this step. In FreeFileSync, proceed as detailed below.
   IMPORTANT: Remember to place the project folder at the exact same path on every machine.
5. Set up the Multi-Machine environment on the Aximmetry machines.
   
6. Load the Unreal scene into the Aximmetry control machine in Editor Data mode.
   At this point, the initial setup is complete, and any modification made on the Unreal Editor machine should appear on the Aximmetry machines in real time.
7. After you have made the scene changes you wanted, Persist the changes on the Unreal Editor machine in AX Scene Editor.
8. Stop the running Aximmetry compound to avoid any errors during the next step.
9. Sync the Unreal project folder containing the new changes (the one on your Unreal Editor machine) to the Aximmetry machines.

Project Folder Synchronization via FreeFileSync

FreeFileSync is an efficient, open-source folder comparison and synchronization tool. It streamlines synchronizing project asset files between workstations by quickly comparing your directories and mirroring the updated files across your network, ensuring every machine holds the exact same data.

Sharing the Root Folder

To use it between different machines, you first have to share the Unreal project root folder on every machine except the one that persisted the session changes.

Select the folder, then go to Properties > Sharing > Share...

Choose the people you want to share it with: select Everyone. Click Share.

Your folder is now shared. Note the file path.

Comparing Folders in FreeFileSync

In FreeFileSync, you see two file paths by default. If you are working with more than two machines, you can add more file path pairs with the green plus button:

The folder that the file path on the left points to is the source folder. This should be the Unreal project folder on the Unreal Editor machine.
The folder referenced on the right is the target folder. This should be the shared Unreal project folder on the Aximmetry machine. Use the path given during the file sharing process.

Above the left panel there is the Compare button. Click it to see the differences between the folders. At the bottom, you can select the comparison view: choose whether you want to see the equal files or the differing files:

You can use this function before starting the Multi-User Edit session to check whether the project folders on the different machines are equal bit by bit, or to see what file changes were made on the Unreal Editor machine during the session.

Synchronizing Folders in FreeFileSync

Above the left panel, there is the Synchronize button. Click it to sync the selected folders.
The synchronization is determined by the Synchronization Settings, which you can open by clicking the green gear button next to the Synchronize button or by pressing F8.
You can also use the simplified quick menu by clicking the arrow next to the gear button. Here you can choose whether to perform a Two Way (identify and propagate changes on both sides), Mirror (mirror the left side to the right side exactly), or Update (copy new and updated files to the right side) sync.

When syncing modifications made during a Multi-User Edit session, choose Mirror, as the goal is for the project folder on all machines to be equivalent.

Filtering Files and Folders in FreeFileSync

In FreeFileSync, you have the option to apply a filter to the file operations. You can set up this function under Actions > Filter settings, by pressing F7, or by clicking the red funnel icon in the upper middle part of the window:

Here you can include or exclude certain files and folders from the synchronization (and from the comparison as well), such as the Saved subfolder of the Unreal scene's project folder:

Troubleshooting

Unsynced Project Folders

This section provides a solution for unsynced project folders between machines during Multi-User Editing. This can occur because:

• the project folders on the different machines were not in sync when the Multi-Edit session was started, or
• Unreal scene modifications were applied via Save instead of Persist during the Multi-Edit session.

An unsynced project folder disrupts the memory connection between machines established during the session, causing the Multi-User Edit setup to break down: the machines might remain connected to the session, but because of the Unreal asset mismatch, the scene fails to load properly in Aximmetry. This means you only see Unreal's frozen placeholder texture instead of your actual editable scene:

This is why it is crucial that you NEVER use Save, only Persist, when Multi-User Editing.

The easiest way to fix this asset mismatch is to delete the current Multi-User session in Unreal.

This is necessary because unsynced files corrupt the whole Multi-User session, so simply re-syncing will not work.

After deleting the session, sync your project folders between the machines, then restart the session. You should now see the Unreal scene load correctly in Aximmetry.