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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Short, late or in stock
For each need: the matching supplier row, the shortfall and the status.
short = max(0, need − stock); late: no stock figure and lead > limit
Supplier stock and lead-time check lib-supply/supply.js64-bit- TakeoffCraft
- DetailCraft
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Values in the reported problems
The required and found values of a shortage or a long lead time in the problems list.
Supplier stock and lead-time check lib-supply/supply.js64-bit- TakeoffCraft
- DetailCraft
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Stock figure from text
Reads a stock cell such as 1,200 or Out of stock as a number, or as in stock or not.
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Lead time in days
Reads a lead time such as 2-3 weeks or 5 business days as a number of days.
weeks × 7; months × 30; business days → ⌈n × 7 ÷ 5⌉; result rounded to 0.1 day
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Price from text
Reads a price cell as a whole number of 1/10000 dollar, the unit the takeoff's rates use.
price = round(n × 10000)
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Short, late or in stock
For each estimate row with a quantity: the matching supplier row, the shortfall and the status.
short = max(0, need − stock); late: no stock figure and lead > limit
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Values in the reported problems
The required and found values of a shortage or a long lead time in the problems list.
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Supplier prices into the price library
Sets a library entry's material rate to the matching supplier row's price.
Supplier stock and lead-time check supply.js64-bit- TakeoffCraft
- DetailCraft
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Value of a number row
The number handed to the app when a person changes a number box.
v = min(max, max(min, typed value))
Numbers typed into the property grid app-propgrid.js Every app64-bit -
Rounding of a slider value
Removes binary noise such as 0.30000000000000004 from a slider's value.
v = round to (decimals of the step + 2) decimals, at most 8
Numbers typed into the property grid app-propgrid.js Every app64-bit -
Value of a slider row
The number handed to the app while a slider is dragged or its box is changed.
v = fix(clamp(value, min, max), step)
Numbers typed into the property grid app-propgrid.js Every app64-bit -
Integer or float
Decides how a number is written.
Numbers sent between people editing together live-client.js Every app64-bit -
Writing a float
Writes a number as 8 bytes.
Numbers sent between people editing together live-client.js Every app64-bit -
Writing an integer
Writes a whole number in the shortest integer form that holds it.
Numbers sent between people editing together live-client.js Every appExact -
Reading a float
Reads a 4-byte or an 8-byte float from a message.
Numbers sent between people editing together live-client.js Every app64-bit -
Reading a 64-bit integer
Reads an unsigned or signed 64-bit integer.
Numbers sent between people editing together live-client.js Every appExact -
Cost of one call
The cost of a call from its token counts and the model's prices.
cost = (in × price in + out × price out) ÷ 1,000,000
Spending on a person's own AI model ai-byok.js Every app64-bit -
Spending today and this month
The cost, tokens and number of calls for the current day and month, and the calls in the last hour.
amount = Σ cost of the calls in the period
Spending on a person's own AI model ai-byok.js Every app64-bit -
Check before a call
Refuses a call when the calls per hour, the day's or month's spending, or the day's tokens could pass a limit.
refuse when spent + worst-case cost > limit; worst case = cost(estimated input, largest allowed output)
Spending on a person's own AI model ai-byok.js Every app64-bit -
Recorded cost and the token estimate
Stores each call's cost and estimates the input tokens of the next request.
estimated tokens = ⌈JSON length ÷ 3⌉ + 500
Spending on a person's own AI model ai-byok.js Every app64-bit -
Flow through a passage
Persons per second through a door or corridor of a given width.
rate = max(0, Fsm × (width − 2 × boundary))
People flow and evacuation time people.js Every app64-bit -
Speed and specific flow at a density
Walking speed and flow per meter of width at a given density of people.
S = k × (1 − 0.266 × D); Fs = S × D; k = 1.4 m/s
People flow and evacuation time people.js Every app64-bit -
Rate and speed of each passage
The flow rate and walking speed each passage gets, from its own values or the defaults for its kind.
People flow and evacuation time people.js Every app64-bit -
Door service time and walking time
How long a door takes per person, how long the passage takes to walk, and each room's distance to an exit in time.
service = 1 ÷ rate; walk = length ÷ speed; to exit = least total walking time
People flow and evacuation time people.js Every app64-bit -
Which way a room empties
The next passage for people in a room: the one with the least remaining walking time to an exit.
keep a hop when toExit(next) < toExit(room) − 1e-9; choose the least walk + toExit(next)
People flow and evacuation time people.js Every app64-bit -
Evacuation results
People evacuated, the time the last person reaches an exit, peak occupancy and density per room, and queues per door.
time = latest arrival at any exit; density = peak people in a room ÷ its area
People flow and evacuation time people.js Every app64-bit -
Joint frames at a pose
Each joint's rotation and offset from its parent at the given joint values.
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Joint torques for a motion (inverse dynamics)
The torque or force each joint needs for given positions, velocities and accelerations, with gravity, external loads and damping.
outward: ω, α, a of each link; F = m × a_com; N = I α + ω × (I ω); inward: τᵢ = axis · n (revolute) or axis · f (prismatic) + damping × q̇ᵢ
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Mass matrix
The joint-space mass matrix at a pose.
column j = rnea(q, q̇ = 0, q̈ = unit vector j) with no gravity, damping or external loads
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Joint accelerations for given torques (forward dynamics)
The acceleration of each joint under applied torques.
M q̈ = τ − h
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Kinetic and potential energy
The mechanism's kinetic, potential and total energy at a pose and velocity.
KE = ½ q̇ᵀ M q̇; PE = −Σ m × (g · p_com)
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Simulated motion over time
Joint positions and velocities at each time step under gravity and applied torques.
RK4: y₊ = y + dt ÷ 6 × (k₁ + 2k₂ + 2k₃ + k₄); steps = round(T ÷ dt); t = step × dt
Rigid-body dynamics of a mechanism dynamics.js Every app64-bit -
Courtyard of a footprint
The rectangle around all pads, grown by a margin.
courtyard = (min(x − w ÷ 2) − m, min(y − h ÷ 2) − m, max(x + w ÷ 2) + m, max(y + h ÷ 2) + m)
Parametric PCB footprints footlib.js Every app64-bit -
Two-terminal chip
Two pads at half the pitch either side of the center.
x = ∓ pitch ÷ 2
Parametric PCB footprints footlib.js Every app64-bit -
Dual-row surface-mount package
Pads in two rows, numbered counter-clockwise from the top left.
y = ((n ÷ 2 − 1) ÷ 2 − i) × pitch; x = ∓ row spacing ÷ 2
Parametric PCB footprints footlib.js Every app64-bit -
Dual in-line through-hole package
Drilled pads in two rows.
y = ((n ÷ 2 − 1) ÷ 2 − i) × pitch; x = ∓ row spacing ÷ 2
Parametric PCB footprints footlib.js Every app64-bit -
Pin header
Drilled pads in one or two rows at a pitch.
x = (r − (rows − 1) ÷ 2) × pitch; y = ((n − 1) ÷ 2 − i) × pitch
Parametric PCB footprints footlib.js Every app64-bit -
Quad flat package
Pads on four sides, numbered counter-clockwise from the top left.
along a side: ((n − 1) ÷ 2 − i) × pitch; across: ± span ÷ 2
Parametric PCB footprints footlib.js Every app64-bit -
Axial through-hole part
Two drilled pads at half the lead pitch either side of the center.
x = ∓ pitch ÷ 2
Parametric PCB footprints footlib.js Every app64-bit -
Ring orientation
The signed area that decides if a ring runs counter-clockwise.
A = ½ Σ (xᵢ·yᵢ₊₁ − xᵢ₊₁·yᵢ)
Polygon triangulation by ear clipping ifc/geo-tri.js64-bit- BimCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
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Cross product and inside test
Which side of a line a point lies on and whether a point is inside a triangle.
cross = (bx−ax)(cy−ay) − (by−ay)(cx−ax)
Polygon triangulation by ear clipping ifc/geo-tri.js64-bit- BimCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
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Hole bridge
The vertex of the outer ring a hole is joined to.
Polygon triangulation by ear clipping ifc/geo-tri.js64-bit- BimCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
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Ear test
Whether a corner can be cut off as a triangle.
Polygon triangulation by ear clipping ifc/geo-tri.js64-bit- BimCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
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Triangulate rings on a plane
The triangles of 3D rings that lie on one plane.
Polygon triangulation by ear clipping ifc/geo-tri.js64-bit- BimCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
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Vertices and loose edges
The point positions of a model definition and its loose edges.
Model points written to USD usd/m3d.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Mesh arrays
The point, normal, UV and color arrays of a mesh.
Model points written to USD usd/m3d.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Number to text
The text a number is written as, by type.
f32: text = shortest s with fround(+s) = fround(x)
Number text in USD files usd/usda-write.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Shortest digits
A number to p significant digits without trailing zeros.
Number text in USD files usd/usda-write.js64-bit- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Type name to number type
Which number type a USD type name uses (32-bit float, half or 64-bit double).
Number text in USD files usd/sdf.jsExact- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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Inline values
A value that the file stores inside its 32-bit payload word.
Floats read from USD files usd/usdc-read.js32-bit in part- CadCraft
- BimCraft
- ModelCraft
- TakeoffCraft
- CivilCraft
- DetailCraft
- PartCraft
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.