Formulas

Formulas work things out from the answers: a worked-out attribute, a component’s quantity or cost, an option’s price. Conditions are formulas that give yes or no, such as a component’s When. Templates are text with attributes in braces.

Every formula field checks what you type against the family. A problem is underlined, with a message beneath it saying what’s wrong and where, such as Unknown attribute [Drive cuont]. Did you mean [Drive count]? (at character 1). When it checks, the field shows what the formula gives and which attributes it uses. A formula with a problem never stops you pressing Save: Save takes you to it instead.

Writing a formula

• Attributes go in square brackets: [Drive count]. Type [ to choose from the family’s attributes.
• Numbers are written plainly: 1200, not 1,200. They’re exact decimals, so money and quantities add up.
• Text goes in double quotes: "Rack 2U". A choice is compared with one of its values by name or code: [Chassis] = "Rack 2U". A value that doesn’t exist is an error when you save.
• Yes and no are yes and no.
• Upper and lower case don’t matter in keywords, function names or attribute names.

Operators

Operator	Meaning	Example
+ - * /	Add, subtract, multiply, divide	[Drive count] * 12 + 150
= <>	Equal, not equal	[Chassis] <> "Tower"
< <= > >=	Less than, at most, more than, at least	[Width] > 900
in (…), not in (…)	One of a list	[Chassis] in ("Rack 1U", "Rack 2U")
between … and …	Within a range, ends included	[Width] between 600 and 900
includes, excludes	For attributes that hold several values	[Extras] includes "Spare fan"
and, or, not	Combine conditions	[Redundant power] and not [Chassis] = "Tower"
( )	Group	([Width] + 50) * 2

Functions

Function	Gives	Example
if(condition, then, otherwise)	One of two values	if([Redundant power], 2, 1)
min(a, b, …), max(a, b, …)	The smallest or largest	max([Drive count], 2)
round(x, places)	Rounded to the nearest, halves away from zero; 0 places if left out	round([Power needed] / 1000, 1)
roundup(x, step)	Up to the next multiple of the step; 1 if left out	roundup([Power needed], 50)
rounddown(x, step)	Down to the multiple of the step; 1 if left out	rounddown([Width], 10)
abs(x)	Without its sign	abs([Offset])
answered([Attribute])	Yes once the attribute has an answer	if(answered([Drive count]), [Drive count], 0)
lookup("Lookup", "Column")	A value from a lookup’s matching row	lookup("Power supplies", "Watts")

Rounding negative numbers

roundup and rounddown always go up or down the number line, so roundup(-1.2) is -1 and rounddown(-1.2) is -2. Excel’s ROUNDUP and ROUNDDOWN go away from and towards zero instead, so they give -2 and -1. For positive numbers they’re the same.

Unanswered attributes

Until an attribute is answered, anything that uses it is unknown, not zero. A component whose quantity is unknown waits until it can be worked out, and a condition that’s unknown doesn’t apply yet. To give a value before then, test it: if(answered([Drive count]), [Drive count] * 12, 0).

Materials and cut pieces

A made part’s materials use formulas per one made part. Some examples for a panel whose frame is cut from bar stock:

Field	Formula	Gives
A material’s Quantity per made part	[Width] * [Height] / 1000000 * 0.2	The litres of coating for the panel’s area
A cut piece’s Pieces	if([Leaves] = 2, 4, 2)	Four rails on a double, two on a single
A cut piece’s Length	[Height] - 40	Each side, in the cutting unit
A cut piece’s Width	[Width] - 100	A piece cut from a sheet, such as an infill

Pieces must be whole numbers, and lengths and widths above zero. A quantity of 0 or less, or no pieces, leaves the row out, so if([Glazed], 1, 0) is another way to make a row optional.

Conditions

A condition gives yes or no: [Chassis] = "Tower" and [Drive count] > 4. A yes/no attribute on its own is a condition: [Redundant power]. Use brackets to group and and or: [Chassis] = "Tower" or ([Drive count] > 4 and not [Redundant power]).

Templates

Descriptions, code templates and messages are text with attributes in braces:

Placeholder	Gives	Example
{Attribute}	The answer, with a number’s unit and decimals	{Memory size} gives 128 GB
{Attribute:code}	The value’s code	RAIL-{Chassis:code} gives RAIL-2U
{Attribute:0.0}	A number in that format	{Power needed:0} gives 450

Type { in a template to choose an attribute. To show a brace itself, write it twice: {{ or }}.

Limits

A formula can be up to 2,000 characters long and nested 32 brackets deep. Something that can’t be worked out, such as a division by zero, shows as a problem on that formula rather than stopping the configuration.