Equations & global variables

Give a number a name, then drive dimensions and feature parameters from it — change the name's value and the whole part re-drives.

Model the intent, not the numbers. Name a value once, point every dimension that depends on it at that name, and one edit re-drives the part.

The variables table

Click empty space so nothing is selected — the right panel then shows the document-level Σ Equations · Global variables.

1. + Add variable adds a row: a Name and a Value or equation.
2. Names start with a letter and hold letters, digits and _ — A, Width, bolt_count. They are case-sensitive.
3. The value can be a plain number (213) or an expression referring to other rows (B/3 + 10).

Rows may reference each other in any order, and each row shows its resolved value live — or its own error, without breaking the others.

Driving a dimension or a parameter

Start any dimension box or PropertyManager number field with = and the rest is an expression:

• =W — this dimension is the width
• =W/2 — always half of it
• =max(T, 2) + 0.5 — never thinner than 2

Set W = 80, sketch a plate with =W and =W/2, extrude it =W/8, then change W to 96 — the sketch re-solves and the extrude re-drives together on the next rebuild.

What you can write

• + - * / %, ^ and parentheses
• sqrt abs floor ceil round min max pow hypot
• sin cos tan asin acos atan atan2 — in degrees, matching every angle the interface shows
• the constants pi and e
• any other variable, by name

It is a real parser, not eval: a file someone sends you cannot run code through an expression.

Diameter dimensions

A ⌀ dimension is stored internally as a radius, but you write the diameter you mean — =B on a ⌀ dimension gives a bore of diameter B, never 2B.

Design tables

The same variables can be driven from a CSV design table — one row per variant, one column per name — which is how a size family is built; see Configurations & design tables.

When it fails

• Unknown name — the row you referenced does not exist or is spelled differently. Check the case.
• A cycle — A = B while B = A cannot resolve; both rows report it and keep their last good values.
• The model didn't move — a broken equation never fails the rebuild. The driven value keeps its last good number and the offending row is flagged, so fix the equation, not the dimension it drives.

Related: Dimensions & constraints · Configurations & design tables · Working with the feature tree

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