CALCULATORS / GEOMETRY AND MASS PROPERTIES

Two-part rectangular enclosure size calculator

Axis-aligned envelope of two supplied bounding boxes.

geometry-minimum-enclosure.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	widthmm	heightmm	areamm^2
	90	60	5400
	80	60	4800

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

enclosure width budget90.00 mm✓ passes

BASELINE INPUTS

widthA50 mmwidthB30 mmheightA40 mmheightB60 mmgap10 mm

CALCULATED

width90 mm

height60 mm

area5400 mm^2

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Enclosure envelope
# Scope: Axis-aligned envelope of two supplied bounding boxes.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

widthA = 50 mm
widthB = 30 mm
heightA = 40 mm
heightB = 60 mm
gap = 10 mm

width := widthA+gap+widthB [mm]
height := max(heightA,heightB) [mm]
area := width*height [mm^2]

check enclosure width budget: width <= 100 mm

scenario alternative: widthA = 40 mm

Calculated from your source · not saved

Baseline · Baseline

enclosure width budget90.00 mm ✓ passes

alternative · alternative

enclosure width budget80.00 mm ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

width: width = widthA+gap+widthB [mm]
height: height = max(heightA,heightB) [mm]
area: area = width*height [mm^2]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

width a: 50 mm
width b: 30 mm
height a: 40 mm
height b: 60 mm
gap: 10 mm

Calculated

width: 90 mm
height: 60 mm
area: 5400 mm^2

Assumptions and limits

Axis-aligned envelope of two supplied bounding boxes.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Enclosure envelope. Inputs: component envelopes; poses; margins. Outputs: minimum bounding dimensions. Model scope: Ideal solids and explicitly described coordinate frames. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: component envelopes, poses, margins
Outputs: minimum bounding dimensions
Modes: calculate, compare, sweep
Drawing: Parametric solid

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS