The Global Parameters command creates and manages a shared parameter set for the active Autodesk Fusion project. Parameters are stored in a dedicated Fusion document inside the _Global Parameters folder at the project root, making them available to any document in the project via the Link Global Parameters command.
- Create a new named parameter set for the active project.
- Edit an existing parameter set — add, modify, or remove parameters.
- Define parameters with a name, numeric value, unit (in, ft, mm, cm, m), and optional comment.
- Mark parameters as Fusion favorites so they appear in the Favorites panel of any consuming document.
- Restore unsaved changes from a previous session if the dialog was cancelled before saving.
- Use warm-start discovery caches to reduce project folder scanning and startup latency.
- An Autodesk Fusion 3D Design must be active.
- The active document must be saved to an Autodesk Hub project.
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Open the Autodesk Fusion Design workspace.
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On the Power Tools panel, select Global Parameters.
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The Parameter Set dropdown defaults to Create New. Leave it set to Create New.
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In the Name field, enter a descriptive name for the parameter set (for example,
Enclosure Constants). -
Use the table to define your parameters:
Column Description (checkbox) Select a row to enable the Delete toolbar button Name Parameter name — must start with a letter; letters, digits, _,",$,°,µare allowedValue Numeric value Unit Unit from the dropdown (in, ft, mm, cm, m) Comment Optional free-text description -
Use the Add toolbar button to insert additional parameter rows.
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Use the Delete toolbar button to remove selected rows.
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Select OK to save.
The command creates a new Fusion design document with the parameter set name in the _Global Parameters folder of the active project, and also writes the parameters directly into the active document.
- Open the Autodesk Fusion Design workspace.
- On the Power Tools panel, select Global Parameters.
- In the Parameter Set dropdown, select the name of the parameter set you want to edit.
- The table populates with the existing parameters.
- Make your changes and select OK to save.
Note: Once you select an existing parameter set, the dropdown locks for that session to prevent accidental mode switching after data has been loaded.
If you cancelled the dialog in a previous session before saving, the command detects the saved state and offers to restore it. Select Yes in the prompt to reload the previous table contents.
The Global Parameters command is located on the Utilities tab, in the Power Tools panel of the Autodesk Fusion Design workspace.
| Rule | Detail |
|---|---|
| Must start with a letter | Digits and symbols are not allowed as the first character |
| Allowed characters | Letters, digits, _, ", $, °, µ |
| Case-sensitive | Width and width are treated as different parameters |
| Reserved names | Fusion unit names (mm, in, ft, deg, rad, kg, s, pi, etc.) are not allowed as parameter names |
| Duplicate names | Each parameter name must be unique within the set |
The following diagrams show how the Global Parameters command interacts with Autodesk Fusion and the project data model.
C4Context
title Global Parameters – System Context
Person(user, "Design Engineer", "Autodesk Fusion user defining shared project parameters")
System(addin, "PowerTools Assembly", "Autodesk Fusion add-in")
System_Ext(fusion, "Autodesk Fusion", "Host application and Python API (adsk.core / adsk.fusion)")
System_Ext(hub, "Autodesk Hub", "Cloud project storage — hosts the _Global Parameters folder and parameter set documents")
System_Ext(cache, "Local Cache", "add-in/cache/ folder — stores document URN, parameter snapshots, and pending (unsaved) session state")
Rel(user, addin, "Opens Global Parameters dialog; defines or edits parameters")
Rel(addin, fusion, "Reads active document and project; creates/updates parameter documents; writes user parameters")
Rel(fusion, hub, "Saves parameter set document to _Global Parameters folder")
Rel(addin, cache, "Writes document URN cache, parameter JSON snapshot, and pending-state JSON on cancel")
C4Component
title Global Parameters – Component View
Person(user, "Design Engineer")
Component(cmd, "globalParameters/entry.py", "PowerTools Command", "Registers the toolbar button; builds and manages the command dialog lifecycle")
Component(cache_mgr, "Cache helpers", "Internal Module", "_write_document_cache / _write_pending_cache / _read_pending_cache / _clear_pending_cache — persist dialog state to local JSON files")
Component(param_doc, "Parameter document helpers", "Internal Module", "_create_parameters_document / _update_parameters_document — create or update a Fusion design doc holding the parameter set")
Component(active_writer, "_write_params_to_active", "Internal Module", "Writes the parameter set directly into the active document's user parameters after creation")
Component(table_ui, "Table UI helpers", "Internal Module", "_add_header_row / _add_data_row / _add_data_row_with_values / _collect_rows / _any_row_checked — manage the editable parameters table in the dialog")
Component(validator, "_validate_and_reason", "Internal Module", "Validates parameter names (regex + reserved word list) and checks for duplicates; drives the OK button state")
Component(api_design, "adsk.fusion.Design", "Fusion API", "userParameters collection — create, update, delete parameters; isFavorite flag")
Component(api_data, "adsk.core.Data / DataFolder", "Fusion API", "Browses project root folder; creates _Global Parameters sub-folder; looks up existing parameter set documents")
Component(api_docs, "adsk.core.Documents", "Fusion API", "open() and saveAs() for the parameter set document")
Rel(user, cmd, "Interacts with dialog")
Rel(cmd, cache_mgr, "Reads/writes pending and document-URN caches on open/cancel/execute")
Rel(cmd, param_doc, "Calls on execute to persist parameter set to Hub")
Rel(cmd, active_writer, "Calls on execute (Create New path) to mirror parameters into active doc")
Rel(cmd, table_ui, "Builds table rows; collects edited values on execute")
Rel(cmd, validator, "Called by validateInputs event and on each inputChanged event")
Rel(param_doc, api_design, "Adds/replaces userParameters in the parameter set document")
Rel(param_doc, api_data, "Navigates project folder tree to find or create _Global Parameters folder")
Rel(param_doc, api_docs, "Opens and saves the parameter set Fusion document")
Rel(active_writer, api_design, "Adds or updates userParameters in the already-open active document")
Global Parameters uses layered cache reads before any Hub scan:
gp_folder_<project-key>.json: project-scoped folder id cache for_Global Parameters.gp_docs_<project-key>.json: project-scoped parameter set list used to pre-populate the Parameter Set dropdown.<active-doc-id>_pending.json: cancel-time unsaved session restore payload.<active-doc-id>_parameters.json: last collected table rows snapshot.
When cache-based resolution fails, the command falls back to Hub scans and then refreshes cache files. On Create New, the command also upserts the new parameter-set {name,id} into gp_docs_<project-key>.json immediately so Link Global Parameters can discover it without waiting for a full rescan.
C4Component
title Global Parameters – Cache Components
Component(cmd, "Global Parameters command", "commands/globalParameters/entry.py", "Dialog lifecycle + parameter persistence")
Component(folder_cache, "Folder cache", "gp_folder_<project-key>.json", "Caches _Global Parameters folder id")
Component(docs_cache, "Docs cache", "gp_docs_<project-key>.json", "Caches parameter-set names and ids")
Component(doc_cache, "Document cache", "<doc-id>.json", "Caches active document identity metadata")
Component(param_cache, "Parameter snapshot cache", "<doc-id>_parameters.json", "Caches collected parameter rows")
Component(pending_cache, "Pending session cache", "<doc-id>_pending.json", "Caches unsaved dialog state for restore")
Component(hub_scan, "Hub discovery fallback", "adsk.core.DataFolder / DataFiles", "Scans root folders and parameter-set files when cache misses")
Component(docs_upsert, "Docs cache upsert", "_upsert_param_docs_cache_entry", "Inserts/updates a single newly-created parameter set in gp_docs cache")
Rel(cmd, folder_cache, "Read on open, write on successful resolve")
Rel(cmd, docs_cache, "Read on open, write after list scan")
Rel(cmd, docs_upsert, "Called after Create New saveAs")
Rel(docs_upsert, docs_cache, "Write single-entry update")
Rel(cmd, doc_cache, "Write on command_created")
Rel(cmd, param_cache, "Write on execute")
Rel(cmd, pending_cache, "Read on open, write on cancel, clear on execute")
Rel(cmd, hub_scan, "Fallback when cache miss/stale")
sequenceDiagram
autonumber
actor User
participant Cmd as Global Parameters
participant Cache as Local Cache
participant Hub as Fusion Hub API
User->>Cmd: Open command
Cmd->>Cache: Read gp_docs and pending cache
alt Docs cache hit
Cache-->>Cmd: Parameter set names
Cmd->>Cmd: Build dropdown without Hub scan
else Docs cache miss
Cmd->>Hub: List docs in _Global Parameters
Hub-->>Cmd: DataFile map
Cmd->>Cache: Write gp_docs
end
User->>Cmd: Save (Create New or Edit Existing)
alt Create New
Cmd->>Cache: Read/resolve gp_folder
alt Folder cache miss
Cmd->>Hub: Scan root folders for _Global Parameters
Hub-->>Cmd: Folder
Cmd->>Cache: Write gp_folder
end
Cmd->>Hub: SaveAs new parameter-set document
Cmd->>Cache: Upsert {name,id} into gp_docs
else Edit Existing
Cmd->>Hub: Open existing parameter-set document
Cmd->>Hub: Overwrite userParameters + save
end
Cmd->>Cache: Clear pending cache
sequenceDiagram
actor User
participant Dialog as Global Parameters Dialog
participant Cache as Local Cache
participant Hub as Autodesk Hub
User->>Dialog: Open Global Parameters
Dialog->>Cache: Check for pending (unsaved) session state
alt Pending cache found
Dialog->>User: Offer to restore unsaved changes
User->>Dialog: Confirm restore
Dialog->>Dialog: Reload table from pending cache
end
User->>Dialog: Fill / edit parameter table
User->>Dialog: Click OK
alt Create New
Dialog->>Hub: Create new Fusion doc in _Global Parameters folder
Dialog->>Dialog: Write parameters into active document
Dialog->>Cache: Clear pending cache
else Edit Existing
Dialog->>Hub: Open and overwrite existing parameter set doc
Dialog->>Cache: Clear pending cache
end
alt User cancels instead
Dialog->>Cache: Write pending cache with current table state
end
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