Rhino 8 Worksession Guide: Split Large Projects Across Your Team

Rhino 8’s Worksession feature lets teams split a large model across multiple files, with team members working on different sections. While one user edits the active file, others can view it as reference geometry. According to McNeel’s Rhino 8 documentation, only one person can edit a file at a time; other users can view and reference it. The steps below cover setting up a shared file structure and managing references during a session.

1. Prepare the project and file-sharing setup

Before starting a Worksession, divide the model into functional sections and keep each editable section in a separate file. For example, team members can work on different parts in separate Rhino files, then add those files as references to one another. Each participant edits their own file and views the other participants’ files as reference geometry.

It is important to distinguish between the session file and the model files. Each user keeps their own .rws file, which contains their Worksession list; these files are not intended to be shared. Rhino model files used as references, however, must be accessible to everyone. Setting up shared access to all linked files helps reduce the risk of missing or unavailable references.

2. Attach reference files and choose the active model

1. Open the Worksession Manager window and click Attach. Alternatively, drag a supported geometry file from Windows Explorer and select Attach file in the dialog.

2. Select the files to attach. Rhino can attach files in various formats that it can import as references, but only .3dm files can be made active and edited.

3. Select the model to edit and make it Active. This closes the current active model and converts it to an attached model; if there are unsaved changes, Rhino prompts you to save them.

4. Save the .rws file using Save or Save As to preserve the session setup.

You cannot edit the geometry in an attached file directly. However, you can use it as input when creating new objects—for example, as a reference for copying or creating a surface from a curve. The reference file’s layers appear as sublayers under the attached file’s name. You can change their color, visibility, and lock status, but you cannot add or delete layers in the attached file.

3. Manage file ownership and updates across the team

Status in Worksession Manager shows which file is open for editing. You can track the lock status of attached files in the Locked column, and view information about who opened a file in the lock icon’s tooltip. This makes it possible to check file ownership and help prevent simultaneous editing attempts on the same file.

When a reference model changes, select Update in Worksession Manager to refresh the selected attached files. Refresh All can be used to reload attached models. Worksession operations cannot be undone, so check which model is active before switching files or sessions, or clearing references.

Rhino can detect conflicts in material, environment, and texture names when importing, attaching, or pasting content, or when attaching and activating a Worksession model. For conflicting content, the relevant options in the Advanced settings section determine the following behavior:

PasteConflictOption is used for pasting, while ImportRenameConflictingEx is used for importing and attaching. If project files contain content with the same name but different settings, it is useful to agree in advance on a behavior that fits the team’s standards.

4. Lighten large reference models

Extensive reference geometry can slow down the Rhino viewport or clutter the workspace with unnecessary objects. The LimitReferenceModel command works by drawing a clipping sphere around the area of interest. Objects outside the sphere or not intersecting it are unloaded from memory. Use the RemoveLimits option to remove the boundaries and restore the previous geometry.

PurgeRefObjects simplifies the view by deleting unwanted Worksession reference objects during a session. This operation cannot be undone. To reload the objects, activate another attached file or click Refresh All in Worksession Manager. For this reason, PurgeRefObjects should not be treated as the same operation as LimitReferenceModel, which limits geometry outside the area of interest: one removes selected reference objects, while the other limits geometry beyond a specified area.

Impact on architecture and visualization workflows

Worksession can be useful in workflows where large architectural models are divided into sections and team members work in separate files. Designers can view geometry in other files without editing it and use it as a reference for new modeling operations. Since geometry in different formats can also be attached, files that Rhino can import can serve as references; however, .3dm is required for active editing.

The documentation does not specify particular hardware requirements or guarantee performance improvements, so do not assume Worksession will speed up every scene. For dense reference models, try narrowing the scope with LimitReferenceModel. Teams should also agree in advance on file access, lock status, and how to handle conflicts in render content.

Common mistakes

• Treating the .rws session file as a shared model file: Each user keeps their own session file; reference models are shared.

• Assuming every attached file can be edited: Only .3dm files can be made active.

• Expecting to undo PurgeRefObjects: The command cannot be undone; to reload the objects, activate a file or use Refresh All.

• Expecting to create or delete layers in reference files: You can change the visibility, color, and lock status of these layers, but you cannot change their layer structure.