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

  • Model to paper

    The scale and offset that place a view on the sheet.

    paper = origin + model ÷ s

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Part of a member inside a view's slab

    The stretch of a member's axis that lies inside the band a plan or elevation shows.

    a = (lo − s0) ÷ k, b = (hi − s0) ÷ k; k = x̂·A

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Corners of a part's box

    The eight corners of a part's section box, moved onto the cut faces at mitre ends.

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Outline of a projected part

    The convex outline of a part's projected box corners.

    pop while cross(o, a, b) ≤ 1e-9

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Hidden parts of a line

    Splits a drawn line into the runs that show and the runs behind a part in front.

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Where two paper lines cross

    The position along one segment where it crosses another.

    t = ((c − a) × q) ÷ (r × q), u = ((c − a) × r) ÷ (r × q)

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • A hole's center and axis

    Where a hole is in the model and which way it goes through the part.

    flange hole: v = ±(depth ÷ 2 − t ÷ 2)

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • An assembly in its main part's coordinates

    The welded-on parts, holes and overall extents of an assembly, measured along and across its main part.

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Weights in an assembly's part list

    The weight of each part, of each line and of the whole assembly in the part list.

    total = Σ n × weight

    Dimensions and views on drawing sheets drawings.js
    • DetailCraft
    64-bit
  • Rounding to six decimals

    The rounding applied to every number written to the file.

    round(v × 10⁶) ÷ 10⁶

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • Text position and height

    Where a line of text sits and how tall it is in the DWG model.

    height = size × 0.718

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • Line and polyline vertices

    The points of each line, polyline and solid fill in the DWG model.

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • Outline of a filled circle

    The polygon used as the boundary of a filled circle.

    (c_x + r·cos(2π·i ÷ 48), c_y + r·sin(2π·i ÷ 48))

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • A number in the DXF text

    How each coordinate is printed in the DXF file.

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • Line weight of a pen

    The line weight written for a layer, in hundredths of a millimeter.

    round(w × 100)

    Drawing sheets as DWG and DXF dwgout.js
    • DetailCraft
    64-bit
  • Model point to screen

    Where a model point is drawn on the canvas.

    Erection movie player erection-html.js
    • DetailCraft
    32-bit, display only
  • Where a pick is at a given minute

    The offset of a lifted piece from its final place while the movie plays.

    Erection movie player erection-html.js
    • DetailCraft
    32-bit, display only
  • Load chart cleaned

    The chart rows kept: sorted by radius, with a capacity that never rises as the radius grows.

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Capacity at a radius

    The chart capacity that applies at a given radius.

    capacity = kg of the first row with radius ≥ r; 0 beyond the last row

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    Exact
  • Weight and center of gravity of a pick

    The weight of an assembly and the point its weight acts at.

    W = Σ w_i; cg = Σ w_i·(a_i + b_i) ÷ 2 ÷ W

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Storey a pick belongs to

    Which storey a pick is erected with, for the order of the sequence.

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Load, radius and share of the chart

    The load on the hook, the working radius, the chart capacity there and the share of it used.

    load = W·(1 + rigging% ÷ 100) + deduction; radius = max(r_pick, r_set); share = load ÷ capacity

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Time of a pick

    How long a pick takes and when it starts and ends.

    travel = (plan distance + top height) ÷ 1000; minutes = hook + travel ÷ speed + set + release; start = max(crane free, supports done)

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Status of a pick

    Whether a pick is fine, over the chart, above the chosen limit, out of reach or too high for the hook.

    over when share > 1; high when share > limit

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Plan totals

    The total weight, the total time, the heaviest pick and the pick that uses most of the chart.

    total kg = Σ W; minutes = max end time

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Figures in the plan's warnings

    The numbers quoted when a pick is over the chart, over the limit or too high.

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Data handed to the movie

    The picks, boxes and times saved into the erection movie page.

    Erection plan: picks, crane loads and times erection.js
    • DetailCraft
    64-bit
  • Concrete strength from the footing's text

    The concrete strength in MPa read from text such as 4000 psi, 28 MPa or C30/37.

    MPa = psi × 0.00689476

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Support reaction as a footing load

    Turns an analysis support reaction into the load on the footing in the footing's own axes.

    P = F_z ÷ 1000; (V_x, V_y) = rot(−F) ÷ 1000; (M_x, M_y) = rot(−M) ÷ 10⁶

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Effective depths

    The depth from the top of the footing to the middle of each layer of bottom bars.

    d_X = H − c − d_bX ÷ 2; d_Y = H − c − d_bX − d_bY ÷ 2

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Service load and its eccentricity

    The total vertical load on the soil and where it acts.

    W = γ_c·A·h + γ_s·A·fill; N = ΣP + W; e_x = (ΣP·x + ΣM_y + h·ΣV_x) ÷ N

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Pressure under a rigid rectangle

    The plane of soil pressure under the footing, with part of the base lifting off when the load is outside the kern.

    q = a + b·x + c·y; inside the kern: a = N ÷ A, b = 12·N·e_x ÷ (A·L²), c = 12·N·e_y ÷ (A·B²)

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Three equations in three unknowns

    Solves the Newton step for the pressure plane.

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Soil force and moment beyond a cut

    The upward soil force on the part of the base beyond a cut, and its moment about the cut.

    V = Σ q·dw·ds; M = Σ q·dw·ds·(t − cut)

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Demand over capacity

    The ratio each check reports and whether it passes.

    ratio = demand ÷ capacity; ok when ratio ≤ 1 + 1e-9

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Sliding and overturning

    The safety factors against sliding on the base and against overturning.

    H = √(V_x² + V_y²); sliding: fs·H ≤ μ·N; overturning: FS = 1 ÷ max(|e_x| ÷ (L ÷ 2), |e_y| ÷ (B ÷ 2))

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Shear and moment on a cut, and the largest moment

    The shear and moment on a cut across the footing, and the cut with the largest moment.

    V = V_soil − ΣP; M = M_soil − Σ(P·arm + M_col + h·V_col)

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Bending steel

    The steel provided per meter, the steel bending needs and the minimum steel.

    M_u per m = |M| ÷ (b ÷ 1000) × 10⁶; A_s provided = A_bar × 1000 ÷ s; A_s,min = ρ_min × 1000 × H

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • One-way shear

    The largest shear at a distance d from each column face against the concrete's shear strength.

    V_u = max |V| at face ± d; capacity = 0.75 × V_c

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Bar development length

    The straight length a bar needs beyond the column face to develop its strength.

    l_d = max(300, f_y ÷ (k·λ·√f′c) × d_b); k = 2.1, 1.7, 1.4 or 1.1

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Hooked bar development length

    The length a hooked bar needs.

    l_dh = max(8·d_b, 150, 0.24·f_y ÷ (λ·√f′c) × d_b)

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Length available for development

    The length of bar from the farthest column face to the end of the footing, less the cover.

    available = side ÷ 2 − (|x_col| + c_col ÷ 2) − cover

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Critical section for punching

    The perimeter at d ÷ 2 from a column, cut off at the footing's edge, with its length, centroid and section properties.

    b_o = Σ l; J = Σ (d·l³ ÷ 12 + l·d³ ÷ 12 along the bending direction) + d·l·arm²

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Punching shear

    The shear stress on the critical section against the concrete's punching strength.

    v_u = V_u ÷ (b_o·d) + γ_v·M·c ÷ J (both directions); v_c = min(0.33, 0.17·(1 + 2 ÷ β), 0.083·(2 + α_s·d ÷ b_o))·λ_s·λ·√f′c

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Share of the base in contact

    The share of the base still pressing on the soil when part has lifted off.

    share = cells with q > 0 ÷ 1600

    Footing design checks foundation.js
    • DetailCraft
    64-bit
  • Settlement at the corner of a loaded rectangle

    The settlement under the corner of a flexible rectangle carrying a uniform pressure on an elastic half-space.

    w = q·b·(1 − ν²) ÷ (π·E) × (m·ln((1 + √(m² + 1)) ÷ m) + ln(m + √(m² + 1))); m = long side ÷ short side

    Settlement, flexible mats, pile groups and retaining walls foundation.js
    • DetailCraft
    64-bit
  • Settlement at the center and corner of a footing

    The elastic settlement at the middle and at a corner of the footing.

    center = 4 × corner of the quarter rectangle

    Settlement, flexible mats, pile groups and retaining walls foundation.js
    • DetailCraft
    64-bit
  • Mat mesh size and concrete stiffness

    The element size of the plate mesh and the concrete's modulus.

    size = max(min(clamp(min(L, B) ÷ 14, 150, 600), max(100, smallest column ÷ 3)), √(L·B ÷ 8000)); E_c = 4700·√f′c

    Settlement, flexible mats, pile groups and retaining walls foundation.js
    • DetailCraft
    64-bit
  • Soil springs under the nodes

    The spring stiffness under each node from the subgrade modulus and the area the node carries.

    A = |d₁ × d₂| ÷ 2 (the two diagonals); k_node = k_s × 10⁻⁶ × Σ A ÷ 4

    Settlement, flexible mats, pile groups and retaining walls foundation.js
    • DetailCraft
    64-bit
  • A column load spread over its footprint

    The force on each node inside a column's footprint.

    R_i = P ÷ n + M_y·dx_i ÷ Σdx² − M_x·dy_i ÷ Σdy²

    Settlement, flexible mats, pile groups and retaining walls foundation.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.