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.
Calculations
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Mat settlement and contact pressure
The largest and smallest settlement of the mat and the largest spring pressure.
q = k_s × w ÷ 1000; reaction = Σ k_node × w ÷ 1000
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Mat bending moments and shear
The largest sagging and hogging moments per meter each way and the largest transverse shear.
M = max and min of the node moments ÷ 1000; V = max √(q_x² + q_y²) away from the columns
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Hogging capacity of plain concrete
The hogging moment a mat with no top bars can take.
capacity = 0.60 × 0.42·λ·√f′c × (H² ÷ 6) × 1000 ÷ 10⁶
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Spring pressure at a point
The soil pressure at any point of the mat from the settlements of the nodes round it.
q = k_s ÷ 1000 × bilinear blend of the four corner settlements
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Pile group reactions
The load each pile takes under a vertical load and two moments.
R_i = P ÷ n + M_x·y_i ÷ Σy² + M_y·x_i ÷ Σx²
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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Cantilever retaining wall
Overturning, sliding and bearing of a cantilever wall with level backfill.
K_a = tan²(45° − φ ÷ 2); P_a = ½·K_a·γ·H_t²; e = B ÷ 2 − (M_r − M_o) ÷ W
Settlement, flexible mats, pile groups and retaining walls foundation.js64-bit- DetailCraft
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A real number in the file
How every length, coordinate, direction component and weight is written.
text = toFixed(6), trailing zeros dropped; |v| < 1e-9 → 0
IFC export ifc.js64-bit- DetailCraft
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Storey of an element
Which storey an element is put in: the highest level at or below its lowest point.
level z ≤ lowest point + 0.5 mm
IFC export ifc.js64-bit- DetailCraft
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Placement of a part
The origin and the two axes each part is placed with, relative to its storey.
location = (p_x, p_y, p_z − level z); Axis = part x; RefDirection = part u
IFC export ifc.js64-bit- DetailCraft
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Profile dimensions
The section dimensions written for each profile type.
IFC export ifc.js64-bit- DetailCraft
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Mitre cut plane
The plane that clips a part's extrusion at a mitre end.
normal = unit(−sg·ku, −sg·kv, sg); point = (0, voff, x0)
IFC export ifc.js64-bit- DetailCraft
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Hole openings
The position, direction, depth and radius of each hole's opening.
depth = thickness + 2; start = center − axis·depth ÷ 2; radius = d ÷ 2
IFC export ifc.js64-bit- DetailCraft
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Cope openings
The box that cuts each cope out of a part.
center v = voff ± (depth ÷ 2 − cope depth ÷ 2 + 0.5); box = (width + 2) × (cope depth + 1) × (cope length + 1)
IFC export ifc.js64-bit- DetailCraft
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Bolts and anchor rods
The placement, diameter and length written for each bolt and rod.
IFC export ifc.js64-bit- DetailCraft
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Reinforcing bar center lines
The center line of each placed bar as lines and true arcs, with the bar's radius.
point = origin + s·ŝ + t·t̂; arc through start, middle and end; radius = d_b ÷ 2
IFC export ifc.js64-bit- DetailCraft
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Length and weight properties
The cut length and weight written in each part's property set.
IFC export ifc.js64-bit- DetailCraft
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Length unit to millimeters
The factor that turns the file's lengths into millimeters.
toMm = prefix × 1000; converted units: toMm = factor × prefix × 1000
IFC import ifc-import.js64-bit- DetailCraft
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A placement's axes
The three axes and origin of an IFC axis placement.
Z = unit(Axis); X = unit(Ref − Z·(Ref·Z)); Y = Z × X
IFC import ifc-import.js64-bit- DetailCraft
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Placements combined
One placement expressed inside another.
X′ = A·X, Y′ = A·Y, Z′ = A·Z, O′ = A·O + O_A
IFC import ifc-import.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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Level heights
The height of each storey, from its placement or its Elevation.
z = round(z × toMm × 1000) ÷ 1000
IFC import ifc-import.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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Numbers in the model file
How the model's numbers are written to the file.
The model file and what it stores model.js64-bit- DetailCraft
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A point of a member
Checks and stores a member's start or end point.
The model file and what it stores model.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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A number in the file
How each length and coordinate is written.
text = toFixed(2); |v| < 0.005 → 0.00
DSTV NC files nc1.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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Reading an NC file back
The header values and block rows read from an NC file.
DSTV NC files nc1.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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.