Resources
Numerical accuracy
The calculations in our apps: the policy each one is under, the precision it runs at, and the code itself.
This device: processor, memory, graphics The standard Precision is not robustness
Calculation policies
A policy says how one family of calculations keeps its precision. Open one to see its calculations, by source file, and their code.
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Cabinet shop drawings as drawing objects
Turns the cabinet plan, elevations, sections, schedule, cut list and nested sheets into lines, polylines, texts, hatches and dimensions of the open drawing (CabinetCraft add-on).
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 6 calculations
64-bit Open item -
CabinetCraft in a drawing: units, room outline and solids
Reads a room from a closed polyline of the drawing in millimeters, converts cabinet shop drawings and 3D solids to the drawing's unit, and decides where the sheets are drawn (CabinetCraft add-on in CadCraft).
- CadCraft
- 7 calculations
64-bit Open item -
CabinetCraft parts, fronts and face frames
Works out the cut-list parts of a cabinet job: face-frame stiles and rails, overlay doors and drawer fronts, drawer boxes, blind panels, fillers and end panels.
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 11 calculations
64-bit Open item -
CabinetCraft room picking and dry-run units
Snaps picked room corners to a grid, decides which way round the picked outline runs, and converts sheet sizes between the job's units and a G-code program's units for the dry run.
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 4 calculations
64-bit Open item -
Cabinets along a wall line
Places cabinets one after another along a wall line picked in the plan, finds which cabinets belong to a front view, and prints areas and lengths of the cut list (Cabinet add-on).
- CadCraft
- 6 calculations
64-bit -
Cabinets as 3D viewport bodies
Turns the cabinet job into boxes and meshes for the 3D viewport: every panel, the floor and the walls with their openings (CabinetCraft add-on).
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 2 calculations
32-bit, display only -
Cabinets on angled and curved walls
The geometry of cabinets on walls that are not at right angles or are curved: arc walls from radius, sweep or three points, cabinets stepped round an arc, and the corner cabinet at any angle (CabinetCraft add-on).
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 16 calculations
64-bit Open item -
Cable routes in trays and conduits on the installation plan
Turns the routes drawn on the plan and the circuits into cables with a route, and into the fill rows of each tray and conduit.
- CadCraft
- 3 calculations
64-bit -
Calc sheet units, functions and driven parameters
The unit factors, powers, functions and conversions of a calc sheet, and the values a sheet writes into the app's parameters.
Every app 64-bit, direct- 13 calculations
64-bit Open item -
Calc sheets
Unit-aware formulas saved with the file: spans, loads, moments, pass or fail checks.
Every app 64-bit, direct- 3 calculations
64-bit Open item -
Calculator results and export
Turns what a process calculator works out into the lines of its results table, its CSV export and the one figure it gives the status bar.
- CadCraft
- BimCraft
- 7 calculations in 2 files
64-bit Open item -
CalculiX deck export and result import
Writes a nonlinear study as a text input deck for the separate CalculiX program and reads its text result file back.
- PartCraft
- 6 calculations
64-bit Open item -
Camera exposure and white balance
The exposure value shown in the render dialog, the exposure in stops, and the color gains for a white-balance temperature.
- BimCraft
- ModelCraft
- 4 calculations
64-bit -
Capital and operating cost
Estimates the purchased and installed cost of process equipment and the yearly cost of its energy.
- CadCraft
- BimCraft
- 5 calculations
64-bit -
Carried, stamped and pasted markup geometry
Where markups land when they are carried onto a revised sheet, where a stamp or a picture is placed, and where copied page content is pasted.
- MarkupCraft
- 6 calculations in 3 files
64-bit Open item -
Check report values
The required and found values written in the Problems panel and in the check report exported as CSV.
Every app 64-bit, direct- 1 calculation
64-bit Open item -
Circles tangent to two or three objects
Finds the circle of a given radius tangent to two picked lines or circles, and the circle tangent to three.
- CadCraft
- 8 calculations
64-bit Open item -
Circuit board outline, holes and part boxes
Reads a KiCad board file into a part: the board outline, its drilled holes and one box per component.
- PartCraft
- 5 calculations
64-bit -
Circuit solver
Operating point, DC sweep, AC response and transient of a circuit of resistors, capacitors, inductors, sources, diodes, transistors and switches.
Every app 64-bit, stated limit- 18 calculations in 2 files
64-bit Open item -
Clash check
Finds pairs of elements whose surfaces run into each other and reports how deep their boxes overlap.
- BimCraft
- 5 calculations
32-bit in part Open item -
Clash check between parts
Finds steel parts and footings that run into each other and reports how deep and where.
- DetailCraft
- 9 calculations
64-bit -
Clear-sky solar irradiance
Estimates the beam and diffuse solar irradiance on a clear day from the day of the year, the sun's height, the site altitude and a climate type.
- CivilCraft
- 1 calculation
64-bit -
Clipping block references to a boundary
Cuts the lines, arcs and fills of a clipped block reference or linked drawing at the clip polygon, and converts the clip between drawing and block coordinates.
- CadCraft
- 10 calculations
64-bit Open item -
Closed-loop joint solver
Finds joint values that make every closed chain of joints in an assembly meet, and reports how many values remain free.
- PartCraft
- 6 calculations
64-bit -
COBie export: sizes, areas and durations
Writes floor elevations and heights, room heights and areas, warranty durations and expected life into the COBie workbook, and reads service life and warranty back from one.
- BimCraft
- 6 calculations
64-bit -
Columns: height and quantities
Works out a column's height from its levels and the length, cross-section area and volume written with it.
- BimCraft
- 4 calculations
64-bit -
Concrete member and slab checks on a solved frame
Checks every concrete beam and column of a solved frame for every strength combination, magnifies the moments of slender columns, and sizes a slab's reinforcement from the plate moments.
- CadCraft
- BimCraft
- DetailCraft
- 11 calculations in 3 files
64-bit -
Concrete member strength to ACI 318-19
The design strengths of a rectangular reinforced concrete section in bending, shear and combined axial force and bending.
- CadCraft
- BimCraft
- DetailCraft
- 9 calculations
64-bit Open item -
Concrete section by strain compatibility
The axial force and moment a rectangular reinforced concrete section carries for a given neutral axis depth, and the depth that balances a given axial force.
- CadCraft
- BimCraft
- DetailCraft
- 5 calculations
64-bit -
Conduit and tray fill, cable schedule
Works out how full a conduit or cable tray is, picks the smallest conduit that holds a set of cables, routes cables through the carriers and lists their lengths.
- CadCraft
- BimCraft
- 8 calculations
64-bit Open item -
Connection autopilot starting sizes
Proposes a connection for every joint that has none: bolt size and count, plate sizes and rod spacing, from the shapes and an optional end shear.
- DetailCraft
- 6 calculations
64-bit Open item -
Connection plates, holes, bolts and cut-backs
Works out where each connection's plates, holes, bolts and welds go and how far the joined members are cut back, from the connection's parameters.
- DetailCraft
- 24 calculations
64-bit Open item -
Constraint values and signs
Measures what a dimensional constraint holds (distance, radius, diameter, angle), records which side or direction a constraint applies to, and decides what an edit moved.
- CadCraft
- 13 calculations
64-bit Open item -
Constraints kept through mirror and trim
Works out again the sense of an angle constraint on mirrored geometry and decides which piece of a trimmed object keeps each constraint.
- CadCraft
- 2 calculations
64-bit -
Constructability checks
Warns about bolts a socket cannot reach, bolts too close for a socket, fillet welds outside size limits, welds a torch cannot reach, and tubes that hold water.
- DetailCraft
- 6 calculations
64-bit -
Construction schedule dates and critical path
Reads and writes a project schedule, and works out each task's earliest and latest dates, its float and the critical path.
- BimCraft
- 5 calculations
64-bit -
Contact and magnet study results
Gathers the results of a contact study between parts and of a 2-D magnet study: maximum stress, displacement and flux density, contact force, and the per-vertex and per-element fields.
- PartCraft
- 10 calculations
32-bit in part Open item -
Contact between parts in stress analysis
Works out the gap between touching parts and the contact forces and stiffness that keep them from passing through each other.
- PartCraft
- 8 calculations
64-bit -
Continuity between curves and between surfaces
Measures the gap, the angle and the curvature difference where two curves join or two surfaces share an edge, and classes the join as G0, G1 or G2.
- ModelCraft
- PartCraft
- 5 calculations
64-bit Open item -
Control program host: placement position and turn
Lets a control program read and set the position, the turn about the vertical axis and the visibility of top-level placements.
- ModelCraft
- 2 calculations
64-bit -
Controller standard functions and integer types
Timers, counters, arithmetic functions and type conversions of the soft controller.
Every app 64-bit, direct- 6 calculations
64-bit Open item -
Coordinate readouts and survey point
Says where a point is: its distance from the project origin, the level it is on, its height above that level and its map grid coordinates.
- BimCraft
- 8 calculations
64-bit -
Coordinate reference systems
Converts project coordinates to and from a named map projection, longitude and latitude, and other systems, and reports grid scale factor, convergence and elevation factor at a point.
- CadCraft
- BimCraft
- CivilCraft
- 17 calculations in 2 files
64-bit -
Coordinate system helpers
Finds the coordinate systems a project's coordinates fit, reads and writes latitude and longitude text, applies a local grid fit, and converts a project's coordinates to another system.
- CivilCraft
- 7 calculations
64-bit -
Cores of a cable on a schematic
Finds which wires a cable marker's slash crosses, in order, for the cable list.
- CadCraft
- 2 calculations
64-bit Open item -
Corner cabinet drilling positions
Works out where the shelf-pin, hinge-plate, fixing, pivot and shaft holes go on the parts of a corner cabinet.
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 7 calculations
64-bit Open item -
Corner cabinets: parts and solids
Builds the cut list, door sizes, hardware counts and 3D solids of L-shaped, diagonal and lazy-susan corner cabinets (CabinetCraft add-on).
- CadCraft
- BimCraft
- ModelCraft
- PartCraft
- 11 calculations
64-bit Open item -
Corridor cross sections and pavement quantities
Sweeps a road or track assembly along an alignment and profile: section stations, edge and shoulder points, targets, daylight points, and the area and volume of pavement courses.
- CivilCraft
- 6 calculations
64-bit -
Costs on the schedule
Prices each element from its quantities, adds the cost up per scheduled task, spreads it over the task's days and totals the cash flow.
- BimCraft
- 13 calculations
64-bit Open item -
Countertop outline and quantities
Finds the run of cabinets a countertop covers, pushes the front edges out by the overhang, and writes the countertop's shape, area, perimeter and front edge length.
- BimCraft
- 4 calculations
64-bit
A policy is added only after its source was read. Each statement can be checked in the code shown on its page; the app repositories are public. When a release changes a calculation, its page says so until it has been read again.
The standard
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64-bit everywhere
Every calculation runs in 64-bit floating point (IEEE 754 double precision), from the number you type to the number you read.
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15 digits, always
A 64-bit number keeps any 15-digit value intact and takes 17 digits to write out in full. Our rule for every calculation: carry all 17 between steps, and order the arithmetic so that avoidable rounding never costs one of the first 15.
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32-bit gets a warning
A 32-bit number keeps about 7 digits. Where a 32-bit step can reach a number you read, the calculation is flagged in the lists below, and the app will warn that the result can have less mathematical precision.
This device
What this browser can see of your machine. It is shown here only and sent nowhere; the desktop app reads the full hardware, a web page cannot.
The apps calculate in 64-bit on every device. Work handed to the graphics processor is the exception: browsers expose graphics processors as 32-bit calculators, which can provide less mathematical precision.
- Processor
- Memory
- Numbers in the apps
- Graphics processor (WebGL)
- WebGPU
A browser reports a rounded or capped view of the machine, never a full inventory: it gives the number of processor threads (not the model), memory rounded down and capped at 8 GB (Chromium only), and one graphics adapter even when a machine has several. What the browser reports about graphics is a capability, not a measurement of the card. The size of a graphics card's memory bus (a 192-bit bus, for example) says how fast data moves, not how precisely it calculates. Most graphics cards can calculate in 64-bit natively, slowly, but WebGL and WebGPU do not offer it to web pages.
Approaches
Every policy takes one of five approaches to keeping its precision.
- Exact values 8 policies
- Constants and factors are held as exact fractions from their definitions. The arithmetic is ordered so that no rounded factor is ever used.
- Exact predicates 1 policy
- Coordinates are 64-bit. The yes-or-no decisions that shape the geometry (which side of a line, inside or outside a circle) are computed exactly, so rounding cannot flip one.
- 64-bit, direct 337 policies
- Every value is a 64-bit number from input to result. Formulas are closed form or a direct solve, and every comparison uses a stated tolerance.
- 64-bit, stated limit 428 policies
- The arithmetic is 64-bit, but the method or the data sets the accuracy: a solver tolerance, a mesh, a step size, a datum shift, a table. The limit is stated where the result is shown.
- Display only 49 policies
- Computed to draw the screen, often in 32-bit on the graphics processor. No number a person reads, saves or exports comes from it.
- 32-bit step, flagged 118 policies
- One step stores or exchanges 32-bit values that reach a number a person reads. It is listed here with its open item, and the step is either moved to 64-bit or the app will warn where the number is read.
Precision is not robustness
Mathematical precision is how many digits a number keeps. Geometric robustness is whether a shape stays valid: every intersection found, every solid closed, every face joined to its neighbors. They are different properties, and a CAD system can have the first without the second.
Every geometric algorithm rests on yes-or-no questions. Is this point left or right of that line? Do these two edges cross? Is this point inside that circle? Each answer is the sign of a small expression. When three points are almost in line, the true value of that expression can be smaller than the rounding error of the arithmetic that computes it, and the sign comes out wrong. That happens at 15 digits as readily as at 7.
One wrong sign is not a small error in the last digit. It is a different decision: an intersection that is missed, two triangles that overlap, a face that points the wrong way, a solid with a gap in it. Every coordinate can be correct to 15 digits while the shape they describe is invalid.
What makes geometry robust
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Exact predicates
The yes-or-no questions are answered exactly. The fast 64-bit answer is used when it is safely away from zero. When it is not, the sign is computed again with as many digits as it takes.
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Decide once
A decision about a shape is recorded as topology, and every later step agrees with it. The same question is never asked twice with a chance of two answers.
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Stated tolerances
Where a tolerance is used it is written down, scaled to the size of the geometry and applied the same way everywhere.
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Local origins
Coordinates far from zero are moved to a local origin before the work, so the digits are spent on the geometry and not on the distance to the origin.
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Valid by construction
Algorithms whose result is guaranteed to be a closed solid, whatever the input, in place of ones that repair the result afterwards.
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More than the language
These choices matter more than the programming language. JavaScript, C++ and Rust all compute with the same 64-bit numbers: the same algorithm is as robust, or as fragile, in each.
Where our apps stand
The list on this page records both properties. Surface triangulation in CivilCraft and BimCraft uses exact predicates. Solid modeling in PartCraft runs on a kernel whose result is a closed solid by construction. The intersections in the CadCraft app use stated tolerances today, and exact tests for the near-parallel and near-tangent cases are an open item. Each policy says which approach it takes.