Takeoff formulas
Choose a measure, filter drawing marks, and calculate quantities with takeoff formulas.
Updated
A Takeoff cell reads drawing marks. For example, area(wall) measures the area of marks assigned the wall preset or tag.
A Formula column calculates from other columns, such as Quantity * Rate. See column types and calculations.
1. Choose a measure
| Measure | Result |
|---|---|
count(…) | One per matching mark, in EA. |
length(…) | Path length, or the perimeter of a closed shape, in LF or m. |
area(…) | Enclosed area, in SF or m². |
volume(…) | Area × the mark's depth, in CY or m³. |
Length, area, and volume need a calibrated page. Marks without suitable geometry or depth are excluded. Counting marks does not need a scale.
2. Filter the marks
Write the filter inside the measure's parentheses.
Presets and tags
Use a preset or tag name, such as count(door) or area(exterior-wall). A preset also includes marks assigned to its nested presets.
Names ignore case and punctuation. Use a hyphen or underscore between words, or quote a name containing spaces: area("Exterior Wall").
Combine conditions
- And:
area(wall & rated)includes marks matching both names. - Or:
count(window, door)includes either name. You can also use|. - Not:
count(door & !temporary)excludes temporary marks. - Group:
area(wall & (rated, fire-wall))combines alternatives.
Filter by page or property
Use =, <=, or >= to compare values:
count(door & page=3) area(window & u_value<=0.3) length(pipe & size>=4 & size<=12) count(door & "Room Name"="Main Bedroom")
Property names and text values are case-sensitive. Quote names or values containing spaces; nested properties use dots, such as spec.size=3068.
The names type, page, status, label, and origin refer to the mark itself. Other names refer to its properties.
Use !finish=oak for “not equal.” The operators !=, ==, <, and > are not supported. To match a tag, use its name directly: count(window), not count(tag=window).
3. Calculate the quantity
Use +, -, *, /, numbers, and parentheses.
Deduct openings using the same measure on both sides:
area(wall) - area(window, door)
Deta tracks deductions separately from the gross quantity.
Add 10% waste after deducting openings:
(area(wall) - area(window, door)) * 1.1
Convert square feet to square yards:
area(paving) / 9
Then set the row's unit to SY. Choosing a unit only changes the label; the formula must perform the conversion.
Units
Deta derives units from the measures. If it cannot determine a unit, the cell shows units? and stays out of quantity totals. Check the calculation, then click the marker to choose a unit if needed.
A chosen unit applies to that row and its expanded groups, not the whole column.
Fixed quantities
Enter 4500 for a fixed number or 4500 LS for a quantity with a unit. These values stop following drawing marks. Enter a takeoff formula again to restore a live quantity.
Warnings and missing results
Hover a warning beside the quantity for its explanation.
| Warning | What to check |
|---|---|
| name? | A named tag, property, or value was not found in this version. Check the spelling and suggested match. |
| units? | Deta cannot determine the unit. Check the formula, then choose a unit. |
| formula? | The expression is invalid. Check its syntax. |
| math? | The arithmetic has no valid result, such as division by zero. |
For an empty or zero result without a warning, check that marks match all filter conditions, measured pages have a scale, and volume marks have a depth. A property of type Tag has no separate value: match its name directly.