Unit Conversion & Precision Math

Paracore extends double, int, decimal, and string with fluent unit helpers. These are defined in UnitExtensions.cs and are globally available in all scripts and the REPL.

How Units Flow Through Paracore

Every numeric getter (GetNum, GetNum(name, unit), etc.) returns values that can be piped through unit helpers:

// GetNum returns raw internal feet (11.811)
wall.GetNum("Length")               // → 11.811

// GetNum(name, unit) converts FOR you
wall.GetNum("Length", "m")          // → 3.6

// Or convert yourself with OutputUnit
wall.GetNum("Length").OutputUnit("m")   // → 3.6
wall.GetNum("Length").FormatUnit("mm")  // → "3600.0 mm"

The engine's internal resolution chain (instance → reflection → type parameters) means you can get type parameters with units too:

door.GetNum("Width", "mm")              // → 900.0  (Width is a type param)
door.GetNum("Height", "m")              // → 2.1   (Height is a type param)

caution

Never hardcode conversions. Use .InputUnit("mm") instead of * 304.8. Use .IsAlmostEqualTo() instead of == for doubles.

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Supported Unit Strings

These strings work everywhere: InputUnit, OutputUnit, FormatUnit, FormatValueOnly, RoundTo, GetNum(name, unit), GetStr(name, unit), etc.

Unit String	Aliases	Type
mm	millimeter, millimeters	Length
cm	centimeter, centimeters	Length
m	meter, meters	Length
ft	foot, feet	Length
in	inch, inches	Length
m2, sqm	square meter, square meters, m², sq.m	Area
ft2, sqft	square foot, square feet, ft², sq.ft	Area
m3, cum	cubic meter, cubic meters, m³, cu.m	Volume
ft3, cuft	cubic foot, cubic feet, ft³, cu.ft	Volume

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Input: User Values → Revit Internal

.InputUnit(unit)

Converts a human-scale number into Revit's internal units (feet / sq.ft / cu.ft). Available on double, int, and decimal.

200.0.InputUnit("mm")       // → 0.656... (200mm in feet)
3.6.InputUnit("m")          // → 11.811 (3.6m in feet)
25.0.InputUnit("m2")        // → 269.098 (25m² in sq.ft)

Use case: preparing a threshold value for comparison against GetNum() results:

var minArea = 25.0.InputUnit("m2");
var largeRooms = GetElements<Room>()
    .Where(r => r.GetNum("Area") > minArea);

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Output: Revit Internal → Human Units

.OutputUnit(unit, decimals)

Converts a Revit internal value from feet into the target unit. Returns a double. Available on double, int, and decimal. Defaults to 2 decimals.

wall.GetNum("Length").OutputUnit("mm")      // → 3600.0
wall.GetNum("Length").OutputUnit("m", 3)    // → 3.600 (3 decimals)
room.GetNum("Area").OutputUnit("m2")        // → 25.46

.FormatUnit(unit, decimals)

Same as OutputUnit but returns a string with the unit suffix appended. Ideal for display and logging.

wall.GetNum("Length").FormatUnit("mm")      // → "3600.0 mm"
room.GetNum("Area").FormatUnit("m2")        // → "25.46 m2"
wall.GetNum("Volume").FormatUnit("m3", 3)   // → "0.720 m3"

.FormatValueOnly(unit, decimals)

Returns the numeric value converted to the target unit as a plain string without suffix. Ideal for CSV/Excel export.

wall.GetNum("Length").FormatValueOnly("mm")     // → "3600"
room.GetNum("Area").FormatValueOnly("m2", 4)    // → "25.4578"

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Precision Snapping

.RoundTo(unit, decimals)

Snaps a raw internal value to the nearest incremental precision of a target unit, then converts it back to internal units. This prevents floating-point drift when setting parameters.

// Without RoundTo: you might set 1999.999997mm instead of 2000mm
wall.SetNum("Base Offset", 2000.0.InputUnit("mm"), "mm");

// With RoundTo: the internal value is exactly 2000mm worth of feet
double cleanValue = wall.GetNum("Length").RoundTo("mm", 0);

This is most useful when you have calculated values and need to snap them to clean construction dimensions (nearest mm, nearest cm, etc.) before writing back to the model.

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Dimension String Parsing

"string".ToMeters()

Parses a dimension string with a unit suffix and returns the value in meters. Defaults to meters if no unit suffix is found.

"500mm".ToMeters()     // → 0.5
"2ft".ToMeters()       // → 0.6096
"0.1m".ToMeters()      // → 0.1
"10".ToMeters()        // → 10.0 (defaults to meters)
"3in".ToMeters()       // → 0.0762

Supports the same unit strings as the other methods: mm, cm, m, ft, in, m2/sqm, ft2/sqft, m3/cum, ft3/cuft.

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Precision-Aware Comparisons

Available on double. All use a default tolerance of 1e-9 feet (~0.0003mm) to handle Revit's floating-point noise. All accept an optional tolerance override.

Floating-Point Warning

Never use == or != for doubles. Revit geometry produces floating-point noise. Always use these precision-aware methods for comparisons.

Equality & Zero

Method	Returns true when
.IsAlmostEqualTo(val, tolerance?)	abs(value - val) < tolerance
.AlmostZero(tolerance?)	abs(value) < tolerance
.IsPositive(tolerance?)	value > tolerance
.IsNegative(tolerance?)	value < -tolerance

if (wall.GetNum("Length").AlmostZero()) { /* skip zero-length walls */ }
if (room.Area.IsPositive()) { /* skip rooms with zero/negative area */ }

Relational Comparisons

Method	Returns true when
.IsLessThan(limit, tolerance?)	value < limit AND not approximately equal
.IsGreaterThan(limit, tolerance?)	value > limit AND not approximately equal
.IsLessThanOrEqual(limit, tolerance?)	value < limit OR approximately equal
.IsGreaterThanOrEqual(limit, tolerance?)	value > limit OR approximately equal

if (wall.GetNum("Width", "mm").IsGreaterThanOrEqual(300)) { /* structural walls */ }
if (room.GetNum("Area", "m2").IsLessThan(10)) { /* small rooms */ }

Comparison with Unit Conversion

Chain InputUnit to create thresholds in human units:

var isLargeRoom = room.GetNum("Area")
    .IsGreaterThan(25.0.InputUnit("m2"));

var isShortWall = wall.GetNum("Length")
    .IsLessThan(1.0.InputUnit("m"));

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Quick Reference

I want to...	Method
Convert value → internal feet	200.0.InputUnit("mm")
Convert internal → human unit	value.OutputUnit("m2", 2)
Display with unit suffix	value.FormatUnit("mm")
Display without suffix (CSV)	value.FormatValueOnly("mm", 2)
Snap to clean construction dim	value.RoundTo("mm", 0)
Parse dimension string → meters	"500mm".ToMeters()
Check if ~zero	value.AlmostZero()
Check if ~equal	value.IsAlmostEqualTo(target)
Check if bigger	value.IsGreaterThan(limit)
Check if smaller	value.IsLessThan(limit)
Check if ≥	value.IsGreaterThanOrEqual(limit)
Check if ≤	value.IsLessThanOrEqual(limit)
Check if positive	value.IsPositive()
Check if negative	value.IsNegative()
Get param in specific unit	el.GetNum("Height", "m")