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

  • A rectangle from a closed outline

    Recognizes a four-point outline as a rectangle and reads its center, axes and size.

    square when |ê_i·ê_{i+1}| ≤ 1e-4; center = mean of the four points

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Matching a profile to the catalog

    Decides whether a profile from the file is one of the catalog shapes.

    match when every |catalog − file| ≤ 0.5 mm

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Reusing a custom profile

    Decides whether two profiles from the file are the same custom profile.

    same when all dimensions agree after rounding to 0.01 mm

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Level heights

    The height of each storey, from its placement or its Elevation.

    z = round(z × toMm × 1000) ÷ 1000

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Grid lines

    Which grid axes become numbered or lettered grid lines, and where.

    x line when |d_y| > 0.9999; y line when |d_x| > 0.9999; position rounded to 0.001 mm

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Member line from the extrusion

    The start and end of a member from its extruded solid.

    start = O × toMm; end = start + ext·depth

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Plate from a rectangular solid

    The thickness, width and length of a plate from the three sizes of its box.

    thickness = smallest size; length = largest; plate when thickness < 0.25 × middle size

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Member rotation and stored coordinates

    The rotation that puts the section the way the file has it, and the values stored for the member.

    rot = atan2(U·v₀, U·u₀) × 180 ÷ π; stored: ends to 0.001 mm, rotation to 0.001°

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Holes from round openings

    The face, position and diameter of each hole read from an opening.

    d = round(2·r × 10) ÷ 10; x, y rounded to 0.001 mm

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Copes from rectangular openings

    The length and depth of a cope read from a box-shaped opening.

    length = round(reach × 2) ÷ 2; depth = round(reach × 2) ÷ 2

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Bolts from fasteners

    The diameter, length, head point and direction of each bolt read from the file.

    d, length rounded to 0.1 mm; head rounded to 0.001 mm

    IFC import ifc-import.js
    • DetailCraft
    64-bit
  • Numbers in the model file

    How the model's numbers are written to the file.

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • A point of a member

    Checks and stores a member's start or end point.

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • Member rotation and minimum length

    Brings a member's rotation into 0 to 360 degrees and refuses a member shorter than 1 mm.

    rotation = ((r mod 360) + 360) mod 360; length = √(Δx² + Δy² + Δz²) ≥ 1 mm

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • Grid lines from spacings

    The position of each grid line from the list of spacings typed.

    at_i = at_{i−1} + spacing_{i−1}

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • Spacings shown for existing grid lines

    The spacings text filled into the grid dialog from the stored grid positions.

    spacing = (at_i − at_{i−1}) to 3 decimals

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • A loose bolt as stored

    The diameter, length, head point and direction kept for a bolt that is not part of a connection.

    d, length, head: round(v × 1000) ÷ 1000; axis_i = round(a_i ÷ |a| × 10⁶) ÷ 10⁶

    The model file and what it stores model.js
    • DetailCraft
    64-bit
  • A number in the file

    How each length and coordinate is written.

    text = toFixed(2); |v| < 0.005 → 0.00

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Header sizes and weights

    The length, section sizes, weight and paint surface written in the header.

    plates: weight = t × steel density ÷ 1000 (kg/m²); others: paint surface = perimeter ÷ 1000

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Skew cut angles of a mitre

    The web and flange cut angles written in the header for a mitred I-shape.

    web = −atan(kv) × 180 ÷ π; flange = atan(ku) × 180 ÷ π

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Web contour with copes

    The outline of the web face, notched for copes or ending on the mitre cut.

    cope corners at (length, depth), (L − length, depth), (L − length, h − depth) …

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Flange contour after copes

    Where a flange starts and ends once the copes on its side are cut.

    x0 = cope length when cope depth ≥ t, else 0

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Contours at a mitre end

    The end points of the web and flange contours where a plane cut crosses them.

    x = x0 + ku·u + kv·v at the web's middle plane and at each flange's outside face

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Hole positions on each face

    The x and y of each hole in the file's own face coordinates.

    web: y = offset + d ÷ 2; flange of an I: y = bf ÷ 2 − offset; plate: y = offset + b ÷ 2

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • Reading an NC file back

    The header values and block rows read from an NC file.

    DSTV NC files nc1.js
    • DetailCraft
    64-bit
  • ASTM bar sizes in metric

    The diameter, mass per meter, area and bend diameter of bars #3 to #11.

    d_b = in × 25.4; mass = lb/ft × 1.48816394; area = in² × 645.16; bend D = 6·d_b (to #8) or 8·d_b

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Metric bar area and mass

    The section area and mass per meter of bars H8 to H40.

    area = π·d² ÷ 4; mass = area × 7850 × 10⁻⁶

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Number of bars and their spacing

    How many bars go across a width at no more than a given spacing, and the spacing that results.

    n = max(2, ⌈w ÷ s − 1e-9⌉ + 1); spacing = w ÷ (n − 1)

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Hook leg length

    The out-to-out length of a standard 90 degree hook leg.

    ASTM: D ÷ 2 + d_b + 12·d_b; BS: the tabulated end projection P

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Cut length of a bent bar

    The length of bar to cut for a straight, L or U shape given its out-to-out sizes.

    ASTM L: A + B − 2k + (π ÷ 2)·r_c; U: A + B + C − 4k + π·r_c; k = D ÷ 2 + d_b, r_c = D ÷ 2 + d_b ÷ 2; BS L: A + B − 0.5r − d; U: A + B + C − r − 2d

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Center line of a bar

    The center line of a bar in its own plane as straight pieces and quarter-circle arcs.

    arc radius r_c = D ÷ 2 + d_b ÷ 2; points c + r_c·(cos a, sin a)

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Length of a center line

    The length along a bar's center line.

    Σ straight lengths + Σ r·π ÷ 2

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Bottom mat bars

    The size, shape, count and position of the bottom bars each way.

    A = run − 2·cover; hook B = min(hook leg, room); offset_i = −width ÷ 2 + cover + d_b ÷ 2 + i·spacing

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Starter bars

    The length and position of each starter bar.

    z0 = bottom + cover + d_bX + d_bY; A = top + projection − z0; position = ((i − (n − 1) ÷ 2)·s_x, (j − (n − 1) ÷ 2)·s_y)

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Clear spacing check

    Warns when bars are closer than the minimum clear spacing.

    clear = spacing − d_b ≥ max(25.4, d_b) for ASTM bars, max(20, d_b) for BS bars

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Concrete volume

    The volume of a footing in cubic meters.

    V = L × B × H × 10⁻⁹

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • Bar marks and schedule weights

    Groups identical bars under one mark and totals their length and weight.

    total length = length × count; weight each = mass × length ÷ 1000; total weight = weight each × count

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • The schedule as a table

    The figures printed in the bending schedule and its export.

    sizes and cut length: whole mm; total length: m, 2 decimals; kg/m: 3 decimals; weights: 2 and 1 decimals

    Reinforcing bars and the bending schedule rebar.js
    • DetailCraft
    64-bit
  • A dimension figure

    The number printed on a dimension line of the shop drawing.

    figure = round(value)

    Single-part shop drawing shop.js
    • DetailCraft
    64-bit
  • Hole stations along the part

    The chain of dimensions from the start of the part through each hole to its end.

    step_i = x_i − x_{i−1}; overall = L

    Single-part shop drawing shop.js
    • DetailCraft
    64-bit
  • Scales of the view

    The scale along the part and the scale across it.

    first n in the list with size ÷ n ≤ room; paper = X0 + x ÷ n

    Single-part shop drawing shop.js
    • DetailCraft
    64-bit
  • Mitre cut angles

    The angle from square of each cut end, in the web's plane and across the flanges.

    angle = atan(|k|) × 180 ÷ π, 1 decimal

    Single-part shop drawing shop.js
    • DetailCraft
    64-bit
  • Weight in the title block

    The weight of one part and of the whole quantity.

    total = weight × count

    Single-part shop drawing shop.js
    • DetailCraft
    64-bit
  • Risers, run and pitch

    The number of risers, the riser height, the run and the pitch.

    n = max(2, ⌈rise ÷ max riser − 1e-9⌉); r = rise ÷ n; run = (n − 1)·going; pitch = atan2(r, going)

    Straight stair geometry stair.js
    • DetailCraft
    64-bit
  • Stringer axis

    The line the stringers run on, and where it meets the lower and upper floor.

    k = r ÷ g; drop = (depth ÷ 2 − 50) ÷ cos(atan k); z(a) = k·(a + g) − drop; a0 = drop ÷ k − g, a1 = (rise + drop) ÷ k − g

    Straight stair geometry stair.js
    • DetailCraft
    64-bit
  • Tread plates

    The size and position of each tread.

    depth = going + nosing; middle = (i − 1)·going − nosing + depth ÷ 2; top = i·r

    Straight stair geometry stair.js
    • DetailCraft
    64-bit
  • Riser, going and comfort checks

    Warnings when the riser, the going or twice the riser plus the going is outside its range.

    102 ≤ r ≤ 178; going ≥ 279; 600 ≤ 2r + going ≤ 650

    Straight stair geometry stair.js
    • DetailCraft
    64-bit
  • Rotation about a vertical line

    The matrix and offset that turn points about a point in plan.

    A = [[c, −s], [s, c]]; t = center − A·center; c = cos(deg·π ÷ 180), s = sin(deg·π ÷ 180)

    Move, rotate and mirror transform.js
    • DetailCraft
    64-bit
  • Mirror in a vertical plane

    The matrix and offset that reflect points across a line in plan.

    A = 2·d·dᵀ − I; t = p₁ − A·p₁; d = (p₂ − p₁) ÷ |p₂ − p₁|

    Move, rotate and mirror transform.js
    • DetailCraft
    64-bit
  • A point through the transform

    The new position of a point.

    p′ = A·p + t

    Move, rotate and mirror transform.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.