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Bind Sheet

In one sentence: Synchronise a rectangular range of cells in the current spreadsheet to a matching range in another spreadsheet — keeping the two ranges in lock-step without manual copying.

Overview

Workbench: Spreadsheet · Menu: Spreadsheet → Bind Sheet (right-click a selection → Bind…)
Toolbar: none · Shortcut: none

The Bind Sheet dialog links a selected range of cells to a source range in another (or the same) spreadsheet. The bound cells mirror the source values automatically on recompute.

Intuition

Imagine a project with several sub-assemblies, each in its own FreeCAD document, and a master document that aggregates key dimensions from all of them. Without Bind Sheet, you would manually copy values between spreadsheets — a maintenance nightmare. With Bind Sheet, the master spreadsheet binds directly to the source ranges in each sub-assembly's spreadsheet, and the values update automatically when the sub-assemblies change.

Within a single document, Bind Sheet is useful for:

  • Lookup tables — bind a range that references a material library to a local working range.
  • Derived parameter sheets — one spreadsheet holds master parameters; a second binds to a subset for a specific sub-system.
  • Read-only display copies — bind to a formula sheet so one view is editable, the other is display-only.

When to use it

  • Synchronising parameter ranges between two spreadsheets in the same document.
  • Linking to ranges in an external document (another .FCStd file).
  • Creating a read-only mirror of an editable parameter range.

When NOT to use it

  • You only need one or two values — a regular cell formula =OtherSheet.AliasName is simpler and more explicit.
  • You need computed/transformed values — Bind Sheet mirrors values as-is. For transformed data (scaled, offset), use formulas.

Step-by-step walkthrough

  1. Select the destination range — the cells in the current spreadsheet where the bound values should appear.
  2. Right-click the selection → Bind… (or Spreadsheet → Bind Sheet).
  3. In the Bind Sheet dialog:
  4. Target spreadsheet — the spreadsheet object to bind from.
  5. Start cell / End cell — the source range in the target spreadsheet.
  6. Binding type:
    • Normal — the bound cells mirror the source values; they cannot be edited directly.
    • Hidden reference — like Normal but the dependency is not shown in the dependency graph (for use with circular-reference workarounds).
  7. Click OK.
  8. The bound cells show the values from the source range and are marked read-only (slightly different appearance).

Binding types

Normal binding

The destination cells are read-only mirrors of the source. Any expression in the source is evaluated; the destination shows the result.

FreeCAD tracks the dependency: if the source changes, the destination updates on recompute.

Hidden reference binding

Like Normal but the dependency link is hidden from FreeCAD's dependency tracker. This is an advanced option used when you need to read values from a spreadsheet that would otherwise create a circular dependency in the regular dependency graph. Use with care — hidden references can mask true circular dependencies.

Clearing a binding

  1. Select the bound range.
  2. Right-click → Bind… → click Discard (or Remove binding in the dialog).
  3. The cells become regular editable cells again (content is the last mirrored value).

Python API

import FreeCAD as App

doc = App.newDocument()

# Source spreadsheet
src = doc.addObject("Spreadsheet::Sheet", "Source")
src.set("A1", "100 mm"); src.setAlias("A1", "BaseLength")
src.set("A2", "50 mm");  src.setAlias("A2", "BaseWidth")
src.set("A3", "20 mm");  src.setAlias("A3", "BaseHeight")
doc.recompute()

# Destination spreadsheet
dst = doc.addObject("Spreadsheet::Sheet", "Mirror")
doc.recompute()

# Bind A1:A3 in dst to A1:A3 in src
# Expression-based equivalent (simpler for small ranges):
dst.set("A1", "=Source.BaseLength")
dst.set("A2", "=Source.BaseWidth")
dst.set("A3", "=Source.BaseHeight")
doc.recompute()

print(dst.get("A1"))   # 100.0 (mirrors Source.BaseLength)

# Change source value
src.set("A1", "150 mm")
doc.recompute()
print(dst.get("A1"))   # 150.0 (auto-updated)

Note: The Bind Sheet dialog creates a range binding using FreeCAD's internal tuple-expression syntax. The Python equivalent above uses individual cell expressions, which are equivalent for small ranges. For large range bindings, use the GUI.

Common mistakes and pitfalls

Bound cells cannot be edited directly

Once a range is bound, the destination cells are read-only. Attempts to edit them directly are silently ignored. To edit: clear the binding first.

Source and destination range sizes must match

The destination selection and the source range must have the same number of rows and columns. A mismatch causes an error in the Bind dialog.

Hidden reference can mask circular dependencies

Using Hidden Reference to work around a circular dependency error usually means the model design has a real logical cycle. Resolve the dependency structure instead of hiding it.

See also