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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World transform
The transform of an object in the scene, through all its parents.
W = M_root × … × M_parent × M_own
USD transforms and placement usd/geom.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Scene units and up axis
The transform from the scene's own units and up axis to meters with Z up.
scale by metersPerUnit; Y-up scenes: rotate 90° about X
USD transforms and placement usd/geom.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Placement of instanced copies
The transform of each copy of a point instancer from its position, orientation and scale.
M = translate(p) × rotate(q) × scale(s)
USD transforms and placement usd/scene.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Writing an object's transform
Stores an object's placement in the exported scene.
USD transforms and placement usd/build.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Attribute value to its storage type
Converts a list of numbers to the number type its USD attribute type calls for.
USD mesh coordinates in saved and exported files usd/build.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Mesh points and extent
Stores the points of a mesh and its bounding box in the scene.
extent = [min x, min y, min z, max x, max y, max z] of the points
USD mesh coordinates in saved and exported files usd/build.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Lamp intensity
Converts a lamp's lumens to the intensity a renderer reads.
intensity = lumens ÷ (683 × area × π)
USD mesh coordinates in saved and exported files usd/build.js32-bit, display only- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Single values in the binary file
Writes one number, tuple or matrix into the binary USD file.
USD mesh coordinates in saved and exported files usd/usdc-write.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Arrays in the binary file
Writes an array of numbers into the binary USD file.
USD mesh coordinates in saved and exported files usd/usdc-write.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Reading a mesh
The points, faces and attached values of a mesh read from a USD scene.
USD mesh coordinates in saved and exported files usd/geom.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Built-in shapes as meshes
A cube, sphere, cylinder, cone, capsule or plane of a USD scene as a mesh.
ring point = (r·cos θ, r·sin θ, z), θ = 2π·j ÷ 24
USD mesh coordinates in saved and exported files usd/geom.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Frame of a member
The origin, the unit direction, the two section axes and the length of a member line.
x = (e − s) ÷ |e − s|; v = unit(Z − x·x_z); u = v × x; u′ = cos a·u + sin a·v, v′ = −sin a·u + cos a·v
Member frames and local coordinates geom.js64-bit- DetailCraft
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Local point to model point
The model coordinates of a point given along the member and across its section.
p = o + x·x̂ + u·û + (v + voff)·v̂
Member frames and local coordinates geom.js64-bit- DetailCraft
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Model point to local point
Where a model point lies along a member and across its section.
d = p − o; x = d·x̂, u = d·û, v = d·v̂ − voff
Member frames and local coordinates geom.js64-bit- DetailCraft
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End face position on a plane-cut end
How far along the part its end face is at a given point of the section, for square ends and mitre cuts.
x = x0 + ku·u + kv·v
Member frames and local coordinates geom.js64-bit- DetailCraft
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Section outline clipped at a height
The part of a section outline below or above a line, used for coped ends.
t = (limit − a_v) ÷ (b_v − a_v); new point = (a_u + (b_u − a_u)·t, limit)
Member frames and local coordinates geom.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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Point inside a section outline
Whether a point lies inside a closed outline.
Clash check between parts clash.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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Reported depth and location
The depth and the point each clash is reported with.
depth = round(depth × 10) ÷ 10
Clash check between parts clash.js64-bit- DetailCraft
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Distance from a point to a member line
The shortest distance from a point to the segment between a member's two ends.
k = clamp((P − a)·(b − a) ÷ |b − a|², 0, 1); d = |P − (a + k·(b − a))|
Finding joints between members connections.js64-bit- DetailCraft
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Is a member vertical
Whether a member stands vertical, the condition for a column to take a connection.
|Δx| < 1 mm and |Δy| < 1 mm and |Δz| ≥ 1 mm
Finding joints between members connections.js64-bit- DetailCraft
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Members end to end in line
Pairs of member ends that meet in line, with the gap between them.
along = d·d̂_a; off = |d − d̂_a·along|; in line when |d̂_a·d̂_b| ≥ 0.9999, off ≤ 1 mm, |d| ≤ 50 mm
Finding joints between members connections.js64-bit- DetailCraft
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Beam end at a column
Which beam ends land on a column, and whether they meet its flange, its web or come in skewed.
flange when |away·v̂| > 0.9999; web when |away·û| > 0.9999; else skew
Finding joints between members connections.js64-bit- DetailCraft
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Members meeting at an angle
Pairs of I-shaped member ends that share a point and are not in line, with the angle between them.
angle = acos(clamp(ê_A·ê_B, −1, 1)) × 180 ÷ π
Finding joints between members connections.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.jsExact- DetailCraft
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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.js64-bit- DetailCraft
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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.js64-bit- DetailCraft
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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.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.