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

  • Plant sizes in project units

    The factor that turns a plant's mature height and spread in meters into project units.

    project units per meter = 1 ÷ (1200 ÷ 3937) for feet

    Overhead line checks: clearances, support loads and sizing powerline/landscape-obstacles.js
    • CivilCraft
    64-bit
  • Tree canopy as a ring

    The outline of a plant's canopy used to find where a span passes over it.

    12 points on the circle of radius r: (x + r·cos(2πk ÷ 12), y + r·sin(2πk ÷ 12))

    Overhead line checks: clearances, support loads and sizing powerline/landscape-obstacles.js
    • CivilCraft
    64-bit
  • A plant as an obstacle

    A single plant's canopy radius, height and ground level as an obstacle under a line.

    radius = max(spread ÷ 2, 0.1); height = mature height

    Overhead line checks: clearances, support loads and sizing powerline/landscape-obstacles.js
    • CivilCraft
    64-bit
  • Foundation volume shown in cubic yards

    The foundation volume in the support's properties, in cubic yards for a feet project.

    yd³ = m³ × 1.307951

    Overhead line checks: clearances, support loads and sizing powerline/powerline-ui.js
    • CivilCraft
    64-bit
  • Length of a span in the network

    The electrical length of each overhead span.

    length = √(Δx² + Δy²) × m per unit

    Power network: load current and voltage drop powerline/network.js
    • CivilCraft
    64-bit
  • Snapping to the nearest node

    Finds the support or equipment a route end or a piece of equipment connects to.

    nearest node with distance × m per unit ≤ snap + 1e−9

    Power network: load current and voltage drop powerline/network.js
    • CivilCraft
    64-bit
  • Resistance, reactance and ampacity of an edge

    The electrical data of a span or cable route, with parallel cables counted.

    R = R₂₀ ÷ n; X = X ÷ n (0.08 or 0.35 Ω/km by default); ampacity × n

    Power network: load current and voltage drop powerline/network.js
    • CivilCraft
    64-bit
  • Loads summed upstream

    The active and reactive power each edge carries, and the current each load draws.

    Q = P·tan(acos pf); I = √(P² + Q²) ÷ (√3·U)

    Power network: load current and voltage drop powerline/network.js
    • CivilCraft
    64-bit
  • Current, voltage drop and node voltage

    The current and voltage drop in each edge and the voltage and cumulative drop at each node.

    ΔU = √3·I·(L ÷ 1000)·(R·cos φ + X·sin φ); drop % += ΔU ÷ (U × 1000) × 100; U node = U·(1 − drop ÷ 100)

    Power network: load current and voltage drop powerline/network.js
    • CivilCraft
    64-bit
  • Numbers in the file

    Turns a value into the fixed-decimal text the file carries, and newtons into decanewtons.

    text = v.toFixed(d); daN = N ÷ 10, 2 decimals

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Signed line angle at each support

    The turn of the line at each support in degrees, counter-clockwise positive.

    turn = atan2 of the span ahead − atan2 of the span behind, wrapped to ±180°

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Support coordinates and heights written

    Each support's position, ground level, pole length, height above ground and line angle as written to the file.

    X = x × m per unit, 3 decimals; Hauteur = typed height × m per unit + embedment

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Section tension and catenary parameter written

    The reference temperature, horizontal tension and catenary parameter of each section as written to the file.

    Parametre = H ÷ w, 3 decimals; TensionIni = H ÷ 10 daN, 2 decimals

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Reading a number

    Turns a field's text into a number, accepting a decimal comma.

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Angles in grades

    Converts a line angle given in grades to degrees.

    degrees = grades × 0.9

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • A study file into a line

    Turns the supports read from a file into a line in project units.

    x = X (m) ÷ m per unit; voltage kV = V ÷ 1000

    Line study file (.DON) export and import powerline/don.js
    • CivilCraft
    64-bit
  • Clear-sky beam and diffuse irradiance

    The irradiance outside the atmosphere, the beam transmittance, and the beam and diffuse irradiance at the ground.

    τ_b = a₀ + a₁·exp(−k ÷ cos Z); G_on = 1367·(1 + 0.033·cos(2πn ÷ 365)); G_bn = G_on·τ_b; τ_d = 0.271 − 0.294·τ_b

    Clear-sky solar irradiance pv/daylight-bim-sky.js
    • CivilCraft
    64-bit
  • Node merging

    One analysis node for every group of points that lie within 1 mm of each other.

    same node when |p − n| ≤ 1 mm

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Splitting a member at the points on it

    The stations along a drawn member where another member's end or a node load lies on it.

    s = (q − start)·u; foot = start + u·s; cut when |foot − q| ≤ 2 mm and 2 mm < s < L − 2 mm

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • End points of each piece

    The two points of every piece a split member becomes.

    p = start + u·s

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Section properties per profile

    Area, second moments of area and torsion constant of each profile in use, with the reduced bending stiffness of cracked concrete.

    Iy′ = f·Iy, Iz′ = f·Iz

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Which column feet are supports

    Decides which column feet are held: those with a base plate, or with no member going lower at that node.

    support when lowest z at the node ≥ node z − 1 mm

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Point load on a split member

    Moves a point load from its distance along the drawn member to the piece it falls on.

    a′ = max(0, a − s0)

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Distributed load on a split member

    Cuts a uniform or linearly varying load into the part that falls on each piece.

    w(s) = w + (w₂ − w)·(s − a) ÷ (b − a)

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • Sections the drawn members use

    The area and second moments of area listed for each profile in the model.

    Analytical frame model from the drawn members analysis.js
    • DetailCraft
    64-bit
  • One bolt's shear strength

    The single-shear design strength of one bolt in kN.

    φRn = 0.75 × Fnv × (π·d² ÷ 4) ÷ 1000

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • End shear from a uniform load

    The end shear of a beam when only a uniform load per meter is given.

    R = w × L ÷ 1000 ÷ 2

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • Shear tab rows and plate

    Bolt diameter, number of rows, edge distance and plate thickness for a shear tab.

    clear = d − 2(tf + r); maxRows = ⌊(clear − 2·edge) ÷ 75⌋ + 1; need = max(2, ⌈R ÷ φRn⌉)

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • End plate rows and plate

    Bolt rows, plate width, thickness and gauge for an end plate.

    rows wanted = max(4, 2·⌈R ÷ φRn ÷ 4⌉); width = max(150, bf rounded up to 10); gauge = max(90, round(0.55·bf ÷ 5)·5)

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • Base plate size and rod spacing

    Plate length and width, rod diameter, hole and rod spacing for a column base.

    length = max(300, (depth + 150) rounded up to 25); sx = length − 100

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • Rounding up to a step

    Rounds a size up to the next multiple of a step.

    ⌈v ÷ step − 1e-9⌉ × step

    Connection autopilot starting sizes autopilot.js
    • DetailCraft
    64-bit
  • Box round each part and footing

    The center, axes and half sizes of the box used for the first, coarse test.

    c = o + x̂·L ÷ 2 + v̂·voff; h = (L ÷ 2, width ÷ 2, depth ÷ 2)

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Do two boxes overlap

    Whether two oriented boxes overlap by more than the tolerance.

    separated on axis l when |T·l| > r_A + r_B − tol

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Point inside a section outline

    Whether a point lies inside a closed outline.

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Distance to the nearest outline edge

    The shortest distance from a point to any edge of an outline.

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

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • How far a point is inside a part

    The distance from a point to the outside of a part, zero when it is outside.

    depth = min(x, L − x, distance to each outline edge)

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Ray to the far side of the material

    How far a ray from an edge runs before it meets another edge of the section, to place a sample point in the middle of a flange or web.

    t = (w × e) ÷ (d × e), u = (w × d) ÷ (d × e)

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Sample points across and along a part

    The points of one part that are tested inside the other.

    stations n = clamp(⌈(t1 − t0) ÷ 10⌉, 2, 40)

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Stretch of a part that can reach the other

    The range along one part's axis where it can meet the other part's box.

    t0 = max(0, min x − pad), t1 = min(L, max x + pad); pad = √(h_u² + h_v²)

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Reported depth and location

    The depth and the point each clash is reported with.

    depth = round(depth × 10) ÷ 10

    Clash check between parts clash.js
    • DetailCraft
    64-bit
  • Plate size written into the profile name

    The thickness and width digits of a plate's profile name, which is how a connection plate's section reaches the built part.

    text = Number(v.toFixed(1))

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Bolt length rounded up to 5 mm

    The length of a bolt from its grip and the allowance.

    length = ⌈(grip + allowance) ÷ 5 − 1e-9⌉ × 5

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Anchor rod hole and washer sizes

    The hole diameter, washer size and washer thickness for an anchor rod, from the table in AISC Design Guide 1.

    mm = inches × 25.4

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    Exact
  • End plate, its holes and bolts

    Where an end plate sits against the column and where each bolt row goes.

    center = N + away·(faceOff + tp ÷ 2); z_i = z_c + ((rows − 1) ÷ 2 − i)·pitch; hole = face ± ŵ·gauge ÷ 2

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Edge distance and spacing checks

    Warnings when bolt edge distances, pitch or gauge are under the EN 1993-1-8 Table 3.3 minimums.

    e1, e2 ≥ 1.2·d0; p1 ≥ 2.2·d0; p2 ≥ 2.4·d0

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Shear tab: beam cut-back

    How far a square, skewed or sloped beam is cut back so every corner of its end clears the column face by the gap.

    setback = max over corners of (faceOff + gap − c·n) ÷ cos A; cos A = dir·n

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Shear tab: plate and bolt row

    The tab's two end points, its rotation, and the position of each bolt in the row.

    length = (rows − 1)·pitch + 2·edge; v_i = ev + ((rows − 1) ÷ 2 − i)·pitch; s_bolt = s_face + eh

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Shear tab: skew and slope

    The beam's skew in plan and its slope, reported with the connection.

    skew = acos(min(1, away·n)); slope = asin(min(1, |dir_z|))

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Base plate and anchor rods

    The base plate's position under the column and the four rod positions and lengths.

    rod = B ± ĉ_v·sx ÷ 2 ± ĉ_u·sy ÷ 2; rod length = embed + grout + tp + projection

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    64-bit
  • Plate washers on the rods

    The size, thickness and position of each plate washer and the hole in it.

    hole = rod + 25.4 ÷ 16; z = top of plate + thickness ÷ 2

    Connection plates, holes, bolts and cut-backs connections.js
    • DetailCraft
    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.