Resources Numerical accuracy

Calculations

Every calculation under our calculation policies: what it works out, its formula and the precision it runs at. Open one to see its code as it is in the released app.

  • 6,917 calculations in 1,248 source files
  • 143 exact
  • 6,286 in 64-bit
  • 335 with a 32-bit step
  • Last reviewed

Calculations

  • Whole plant counts from percentages

    Splits a number of plants among species so the counts add up to exactly that number.

    count = ⌊pct ÷ Σpct × n⌋, then the leftover goes to the largest remainders

    Planting: bed and hedge fills, planted areas and their quantities landscape/planting.js
    • CivilCraft
    64-bit
  • Spacing from the plant list

    The spacing a bed or hedge is filled at when none is typed: the species' spacings weighted by their share.

    s = Σ (pct × spacing) ÷ Σ pct

    Planting: bed and hedge fills, planted areas and their quantities landscape/planting.js
    • CivilCraft
    64-bit
  • Plants in a bed

    The position of every plant in a bed at the given spacing and pattern, and the count per species.

    grid step s, row pitch s (square) or s·√3 ÷ 2 (triangular); keep when inside and at least s ÷ 2 − 1e-9 from the edge

    Planting: bed and hedge fills, planted areas and their quantities landscape/planting.js
    • CivilCraft
    64-bit
  • Plants along a hedge

    The number and positions of plants along a hedge line in one or two rows.

    n = ⌊length ÷ s + 1e-9⌋ + 1; first plant at (length − (n − 1)·s) ÷ 2

    Planting: bed and hedge fills, planted areas and their quantities landscape/planting.js
    • CivilCraft
    64-bit
  • Offset of an open line

    A line moved sideways by a distance with mitred corners, used for hedge and path edges, obstacle footprints and IFC bodies.

    corner = p + m × d ÷ max(0.25, m·n₁), m = normalized sum of the two edge normals

    Planting: bed and hedge fills, planted areas and their quantities landscape/planting.js
    • CivilCraft
    64-bit
  • Default build-up depths

    The topsoil and mulch depths a new planted area starts with, in project units.

    feet = round(meters ÷ 0.3048 × 100) ÷ 100

    Planting: bed and hedge fills, planted areas and their quantities landscape/planted.js
    • CivilCraft
    64-bit
  • Plants in a clipped planted area

    The plants of a planted area after paving, walls and steps are cut out of it.

    keep when inside what is left and at least s ÷ 2 − 1e-9 from a cut edge

    Planting: bed and hedge fills, planted areas and their quantities landscape/planted.js
    • CivilCraft
    64-bit
  • Planted area quantities

    The net area, perimeter, edging length, topsoil and mulch volumes and plant count of a planted area.

    topsoil = net area × topsoil depth; mulch = net area × mulch depth; edging = outline length left after clipping

    Planting: bed and hedge fills, planted areas and their quantities landscape/planted.js
    • CivilCraft
    64-bit
  • Planted area quantities for takeoff

    The area, topsoil, mulch, membrane and edging quantities passed to TakeoffCraft.

    qty = round(v × 100) ÷ 100; cubic yards = cubic feet ÷ 27

    Planting: bed and hedge fills, planted areas and their quantities landscape/planted.js
    • CivilCraft
    64-bit
  • Overlap area of two modifiers

    The plan area where two ground-shaping objects overlap.

    overlap = |area of a| − area of (a with b cut out)

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/stack.js
    • CivilCraft
    64-bit
  • Cut and fill per modifier

    The cut volume, fill volume and area that each ground-shaping object accounts for.

    cell = √(W × H ÷ 200000); fill += (z proposed − z existing) × cell² when positive, cut when negative

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/stack.js
    • CivilCraft
    64-bit
  • Spot level and gradient

    The level at a point, or the fall, run, percent and ratio between two points on the surface.

    pct = |z₂ − z₁| ÷ run × 100; ratio = run ÷ |z₂ − z₁|

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/stack.js
    • CivilCraft
    64-bit
  • Typical thresholds in project units

    The level difference that counts as meeting and the drop that counts as a trip edge.

    meet = 0.01 m × k; drop = 0.15 m × k; k = 1 ÷ 0.3048 for feet

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/problems-landscape.js
    • CivilCraft
    64-bit
  • Paving level at a point

    The finished level of a paved area at any point: flat, on its cross-fall plane, or on its cone to a drain.

    cross: z = z₀ − (pct ÷ 100)((x − cx)·cos a + (y − cy)·sin a); drain: z = z₀ + (pct ÷ 100) × distance to the drain

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/problems-landscape.js
    • CivilCraft
    64-bit
  • Ground against a wall's top and footing

    Finds where the ground on the high side is above the wall's top or the ground on the low side is below the footing's top.

    over = max(ground left, ground right) − top; footing shows = footing − min(ground left, ground right)

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/problems-landscape.js
    • CivilCraft
    64-bit
  • Steps against the paving they land on

    The level difference between a flight's bottom or top and the paving at that point.

    d = z of the flight's end − paving level there

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/problems-landscape.js
    • CivilCraft
    64-bit
  • Planted area level against a paving edge

    The largest level difference between a planted area's finished level and the paving along the edge they share.

    d = area level − paving level at the midpoint of each cut edge

    Ground modifiers: cut and fill, overlaps, level labels and junction checks landscape/problems-landscape.js
    • CivilCraft
    64-bit
  • Where the section line is inside an outline

    The stretches of the section line, as distances along it, that lie inside a closed outline.

    d = distance to the segment start + t × segment length, for every crossing t

    Landscape sections and detail drawings landscape/section.js
    • CivilCraft
    64-bit
  • Where the section line crosses an open line

    The distances along the section line where it crosses a wall or other open line.

    d = distance to the segment start + t × segment length

    Landscape sections and detail drawings landscape/section.js
    • CivilCraft
    64-bit
  • Distance along and across the section line

    How far along the section line a point is and how far to its side, used to pick the plants drawn in the section.

    t = clamp(((p − a)·(b − a)) ÷ |b − a|², 0, 1); offset = ±|p − (a + t(b − a))|

    Landscape sections and detail drawings landscape/section.js
    • CivilCraft
    64-bit
  • Proposed ground level at a distance

    The level of the proposed ground at a distance along the section, between the cut's points.

    z = z₀ + (d − d₀) ÷ (d₁ − d₀) × (z₁ − z₀)

    Landscape sections and detail drawings landscape/section.js
    • CivilCraft
    64-bit
  • Build-up layers under the ground line

    Each layer of a paving or planted-area build-up drawn as a band hanging below the proposed ground.

    top of layer = ground − Σ thickness of the layers above; y = z × vertical exaggeration

    Landscape sections and detail drawings landscape/section.js
    • CivilCraft
    64-bit
  • Wall at the section line

    The top and footing levels of a wall where the section line crosses it.

    values of the wall station nearest the crossing point

    Landscape sections and detail drawings landscape/section-ls.js
    • CivilCraft
    64-bit
  • Steps in profile

    The stepped outline of a flight where the section line passes through it.

    risers climbed = ⌊distance along the flight ÷ going⌋ + 1; z = bottom + risers × riser

    Landscape sections and detail drawings landscape/section-ls.js
    • CivilCraft
    64-bit
  • Plants near the section line

    The plants drawn in a section, with their height and spread in project units.

    h = height (m) ÷ k; k = 0.3048 for feet

    Landscape sections and detail drawings landscape/section-ls.js
    • CivilCraft
    64-bit
  • Scale of a section on its sheet

    Picks the standard scale a section is drawn at and the paper millimeters per project unit.

    k = real ÷ n; real = 1000 mm per m or 304.8 mm per ft; n = first of 10, 20, 25, 50, 100, 200, 250, 500, 1000, 2000 with real ÷ n ≤ fit

    Landscape sections and detail drawings landscape/section-ls.js
    • CivilCraft
    64-bit
  • Scale of a detail

    Picks the standard scale of a wall, paving or steps detail and the paper millimeters per project unit.

    k = per ÷ n; per = 1000 or 304.8; n = first of 5, 10, 20, 25, 50, 100 with 1 ÷ n ≤ fit ÷ per

    Landscape sections and detail drawings landscape/sheets.js
    • CivilCraft
    64-bit
  • Wall detail: batter and footing as drawn

    The lean of the wall face and the footing shown in a wall's detail drawing.

    batter offset = tan(batter°) × (top − footing) × k; footing drawn = min(0.6 × depth, 0.3 m)

    Landscape sections and detail drawings landscape/sheets.js
    • CivilCraft
    64-bit
  • Formula evaluation

    The value of a parsed formula for one row.

    + − × ÷ % ^ in 64-bit; round(x, d) = round(x × 10ᵈ) ÷ 10ᵈ

    Worksheets: formulas, column rounding and totals landscape/worksheet.js
    • CivilCraft
    64-bit
  • Numbers to and from text inside a formula

    How a value is read as a number, and how a number is written when it is joined into text.

    text of a number = round(v × 10⁹) ÷ 10⁹

    Worksheets: formulas, column rounding and totals landscape/worksheet.js
    • CivilCraft
    64-bit
  • Rounding a cell to its column's decimals

    Applies the column's decimals setting to a cell.

    cell = Number(v.toFixed(dec))

    Worksheets: formulas, column rounding and totals landscape/worksheet.js
    • CivilCraft
    64-bit
  • Sum, count, average, minimum and maximum

    The total of a column over a group or the whole worksheet.

    sum = Σ cells; average = Σ cells ÷ n

    Worksheets: formulas, column rounding and totals landscape/worksheet.js
    • CivilCraft
    64-bit
  • Rows, groups, subtotals and totals

    Builds the worksheet's rows from the objects, grouped and sorted, with subtotals and a total line.

    Worksheets: formulas, column rounding and totals landscape/worksheet.js
    • CivilCraft
    64-bit
  • Load per meter of conductor

    The vertical load (weight and ice), the wind load and their resultant per meter of conductor in one load case.

    ice = π((D ÷ 2 + t)² − (D ÷ 2)²) × ρ × g; w_v = m·g + ice; w_h = wind pressure × (D + 2t); w = √(w_v² + w_h²)

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Ruling span

    The equivalent span of a section between dead-ends.

    L_r = √(Σ L³ ÷ Σ L)

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Axial stiffness and thermal expansion

    EA in newtons and the expansion coefficient per degree from the library's values.

    EA = E (GPa) × 10⁹ × area (mm²) × 10⁻⁶; α = α₆ × 10⁻⁶

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Change of state

    The horizontal tension in a new load case and temperature, from a known tension in another.

    H³ + K·H² − M = 0; K = EA·(w₁²L² ÷ (24H₁²) + α(t₂ − t₁)) − H₁; M = EA·w₂²L² ÷ 24

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Catenary of one span

    The lowest point, sag, conductor length and the tension at each support of a span, level or inclined.

    a = H ÷ w; x₀ = L ÷ 2 − a·asinh(dz ÷ (2a·sinh(L ÷ 2a))); y(x) = a·(cosh((x − x₀) ÷ a) − cosh(x₀ ÷ a)); length = a·(sinh((L − x₀) ÷ a) + sinh(x₀ ÷ a)); T = H·cosh(x ÷ a)

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Horizontal tension for a support-tension limit

    The horizontal tension at which the support tension of the level ruling span equals a limit.

    find H with H·cosh(L_r·w ÷ 2H) = T

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Meeting the tension limits on the real spans

    Lowers the reference tension until every support-tension limit holds on the actual spans, then reports which limits hold.

    H ← H ÷ max(T_max ÷ limit); holds when value ≤ limit × (1 + 1e−6)

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Stringing table

    Tension, sag and conductor length of every span at each stringing temperature, in still air without ice.

    per temperature: change of state from the reference, then a catenary per span

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Unbalanced ice load at a suspension support

    The longitudinal pull on a support when one adjacent span is iced and the other is bare.

    dT = max(|H iced, left − H bare, right|, |H iced, right − H bare, left|)

    Overhead conductor sag and tension powerline/sag.js
    • CivilCraft
    64-bit
  • Starter library conductor data

    The area, diameter, mass, strength, stiffness, expansion and resistance of the generic stranded conductors that come with the app.

    mass = 1.02 × Σ area × density; strength = 0.9 × Σ area × wire strength; R₂₀ = 1.02 × resistivity ÷ area × 1000

    Overhead conductor sag and tension powerline/library.js
    • CivilCraft
    64-bit
  • Line angle at each support

    The turn of the line at each support, in degrees.

    turn = |atan2 of the span ahead − atan2 of the span behind|, wrapped to 0 … 180°

    Overhead line checks: clearances, support loads and sizing powerline/model.js
    • CivilCraft
    64-bit
  • Suspension, angle or dead-end

    Decides each support's role from the line angle when none is set.

    dead-end when turn ≥ dead-end angle; angle when turn > suspension angle

    Overhead line checks: clearances, support loads and sizing powerline/model.js
    • CivilCraft
    64-bit
  • Chainage of the supports

    The cumulative horizontal distance along the line at each support, in project units.

    ch = Σ √(Δx² + Δy²)

    Overhead line checks: clearances, support loads and sizing powerline/model.js
    • CivilCraft
    64-bit
  • Attachment height

    The elevation at which the conductor is attached at each support, in meters.

    attach = ground × m per unit + height above ground − fitting drop − insulator length; embedment = height ÷ 10 + 0.5 when the item gives none

    Overhead line checks: clearances, support loads and sizing powerline/checks.js
    • CivilCraft
    64-bit
  • Span length and level difference

    The horizontal length of each span and the difference in attachment height between its ends.

    L = √(Δx² + Δy²) × m per unit; dz = attach right − attach left

    Overhead line checks: clearances, support loads and sizing powerline/checks.js
    • CivilCraft
    64-bit
  • Clearance to the ground along a span

    The lowest height of the conductor above the ground in each load case, and where it is.

    clearance = min over samples of (attach + y(x) − ground); samples = max(20, ⌈L ÷ 2⌉) + 1

    Overhead line checks: clearances, support loads and sizing powerline/checks.js
    • CivilCraft
    64-bit
  • Clearance over an obstacle

    The height of the conductor above each obstacle the span crosses in plan, in the worst load case.

    clear = min over cases of (attach + y(t × L)) − top; top = the obstacle's own top, or ground + height

    Overhead line checks: clearances, support loads and sizing powerline/checks.js
    • CivilCraft
    64-bit

A calculation is added only after its source was read. Each statement can be checked in the code shown on its policy's page; the app repositories are public. When a release changes a calculation, its page says so until it has been read again.