Calculator

A small calculator that stays open beside the model. It works out expressions with lengths (metres) and angles, keeps a history and remembers the last result.

Calculator

Opens the Calculator window. The window is not modal: you can leave it open and keep working in the view. If it is already open, the command brings it forward.

Where to find it

Tools tab → Calculate group → Calculator (Calculator).

How to

Click Calculator. The cursor is in the Expression box.
Type an expression, for example sqrt(3^2 + 4^2) m, 2.5 m + 30 mm, sin(30 deg) or atan2(1, 1).
Press Enter or click Work out. The result appears under the box and the line is added to the top of the History list. The box is cleared.
Click the copy button next to the result to put the result text on the clipboard.
Double-click a line in History to bring its expression back into the box for editing.
Click Clear history to empty the list, or Close (or Esc) to close the window.

Numbers and units

Numbers use a dot as the decimal mark and may have an exponent: 1.5, 2e3, 1e-5.
A unit written after a number or after a parenthesis makes it a length or an angle: 5 mm, (1 + 2) m, pi rad.

Unit	Meaning
m, mm, cm, km	Length
deg (or °), rad	Angle

A result that is a length is shown in metres (12.5 m), an angle in degrees (30°), a plain number without a unit. Trailing zeros and rounding noise are removed (0.1 + 0.2 reads 0.3).

Operators

+ - * / ^ and parentheses. ^ is right-associative (2^3^2 is 2^9).

Combination	Result
length + length, angle + angle, number + number	Same kind
length or angle × number, or ÷ number	Same kind
length ÷ length, angle ÷ angle	Plain number
length + angle, length × length, number ÷ length	Error
`^`	Plain numbers only

Functions and constants

Function	Takes	Gives
sqrt, ln, log, exp	A plain number (`ln` and `log` need more than zero, `sqrt` needs zero or more)	Plain number; `log` is base 10
sin, cos, tan	An angle, or a plain number taken as degrees	Plain number
asin, acos, atan	A plain number	Angle
atan2(a, b)	Two values of one kind	Angle
pow(a, b)	Two plain numbers	Plain number
abs, floor, ceil	One value	Same kind
round(x) or round(x, digits)	A value and optionally 0 to 15 digits	Same kind
min, max	One or more values of one kind	Same kind

The constants are pi and e (case does not matter).

Variables and the last result

ans is the result of the last successful calculation.
x = 2 m stores the value in the variable x. The result is also stored in ans. Names are not case sensitive. A name that is a function, a unit, a constant or ans cannot be a variable.
An expression that starts with +, *, / or ^ continues from ans: after 3 m, typing * 2 gives 6 m.
Clear history removes the list but keeps the variables.

If something goes wrong

The message is shown in red under the box with a warning sign. Nothing is added to the history.

Message	What to do
Type an expression.	The box is empty.
Unexpected '…' at position N.	Fix the character at that position.
The expression ends too soon. / A closing parenthesis is missing.	Complete the expression.
Unknown function '…'. / Unknown name '…'.	Check the spelling; set a variable first with `x = …`.
Cannot add or subtract a length, an angle and a plain number.	Give both sides the same kind.
Cannot multiply two lengths or angles. / Cannot divide by a length or an angle.	Only a number can multiply; divide only by a number or by a value of the same kind.
Division by zero.	Change the divisor.
'…' takes a plain number. / '…' takes an angle or a plain number.	Remove the unit from the argument.
'…' takes N argument(s). / '…' takes N to M arguments.	Fix the argument count.
The arguments of '…' must be of one kind.	Use the same unit in all arguments.
The square root of a negative number. / The logarithm of zero or a negative number.	Change the argument.
'…' already has a unit.	A unit is written once.
A power takes plain numbers.	Remove units from the base and exponent.
'…' cannot be used as a variable name.	Pick another name.
The result is not a finite number.	The value is too large or undefined.