The following operators are supported in parameters and dimension edit boxes. Use them to create the required expression.
Algebraic operators
Autodesk Inventor supports the following algebraic operators:
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+ |
addition |
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- |
subtraction |
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% |
floating point modulo |
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* |
multiplication |
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/ |
division |
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^ |
power |
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( |
expression delimiter |
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) |
expression delimiter |
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; |
delimiter for multiargument functions Note: Comma was not used because it would conflict with floating point.
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decimal delimiter ("." vs ",") in European countries. |
Order of operations
Edit boxes use the algebraic order of operations, shown in the following table in descending precedence.
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Operation |
Symbol |
Example |
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parenthesis |
( ) |
(sin(15 deg)) |
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exponentiation |
^ |
width^2 |
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negation (unary subtraction) |
- |
(-2.00 + length) |
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multiplication or division |
* or / |
sin(pi/4 rad) or (0.5 * base * height) |
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addition or subtraction |
+ or - |
(-2.00 + height - 0.35 * base) |
Syntax
The edit box uses the units specified in the default document properties. If you do not specify units in an edit box, terms and coefficients are assigned default units. An expression is evaluated according to the algebraic order of operations and default unit values.
If an expression contains syntax errors, they are shown in red. If no syntax errors are found, the characters are shown in black.
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Syntax errors |
Exponents are applied to units as well as the expression, as shown in this example. 2 + 3^3 The edit box assigns default units to all terms unless a unit is specified. The results are in error because dissimilar units cannot be added: 2 mm + (3 mm)^3ul is evaluated as 2 mm + 27 mm^3. Because the units are ambiguous, the expression is shown in red to indicate an error: 2 + 3^3 Including units and specifying which units are unitless results in the correct evaluation: 2 mm + ((3 ul) ^ 3 ul ) * 1 mm. |
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Typecasting |
The edit box does not allow assignment of units to an expression. The following example is not permitted: (-2.00 + 3^3) m^2 |
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Unit evaluation |
Units are evaluated before the arithmetic portion of an expression. Therefore, the power operator applies to a unit before it applies to an adjacent numeric value. For example: 2 m^2 does not evaluate to 4 square meters, but rather means 2 square meters. The correct syntax is: (2 m)^2 = 4 m^2 |
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Correct syntax |
In expressions, assign a unit to each numerical value in the expression. The following expression is in error because the system expects default units: (2 + 1 * (3^2)) Use "ul" to indicate a unitless value: 2 mm + 1 mm * (3ul^2ul). When entering an angle, the default unit is degrees. To enter radians, use this syntax: (-0.25 deg * 3.1415 rad/1 deg) + (2ul * 3.1415 ul ) * 1 rad |
Units
Autodesk Inventor supports many unit types. This partial list shows some common units. The unit types may be used in all uses where a parameter may be entered, such as equations/
Parameters panel
Parameters
to open the Parameters dialog box. Click Add to add a user parameter and then click the Units column. |
Length |
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"millimeter" "mm" |
"centimeter" "cm" |
"meter" "m" |
"inch" "in" |
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"foot" "ft" |
"micron" |
"nauticalMile" |
"mil" |
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Mass |
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"gram" "g" |
"lbmass" |
"slug" |
"ouncemass" |
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Time |
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"second" "s" |
"hour" "hr"" |
"minute" "min" (might conflict with milli-inch) |
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Temperature |
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"Kelvin" "k" |
"Celsius" "c"" |
"Farenheit" "f" |
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Angularity |
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"radian" "rad"" |
"degree" "deg" "°" |
"grad" |
"steradian" "sr" |
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Velocity |
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"Meters Per Second" "mps" |
"Feet Per Second" "fps" |
"Miles Per Hour" "mph" |
"Revolutions Per Minute" "rpm" |
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Area |
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"circular mil" |
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Volume |
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"liter" "l" |
"gallon" "gal" |
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Force |
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"newton" "N" |
"dyne" |
"lbforce" |
"ounceforce" |
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Pressure |
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"pascal" "Pa"" |
"psi" |
"ksi" |
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Power |
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"watt" "W"" |
"horsepower" "hp" |
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Work |
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"joule" "J" |
"erg" |
"calorie" "cal"" |
"btu" |
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Unitless |
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"unitless" "ul"" |
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Electrical |
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"ampere" "A" |
"volt" "V" |
"ohm" |
"coulomb" "C" |
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"farad" "F" |
"gamma" |
"gauss" |
"henry" "H" |
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"hertz" "Hz" |
"maxwell" |
"mho" |
"oersted" |
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"siemens" "S" |
"tesla" "T" |
"weber" "Wb" |
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Luminosity |
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"candela" "cd"" |
"lumen" "lm" |
"lux" "lx" |
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Substance |
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"mole" |
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Prefixes
Autodesk Inventor supports the following prefixes:
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"exa" "E" |
1.0e18 |
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"peta" "P" |
1.0e15 |
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"tera" "T" |
1.0e12 |
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"giga" "G" |
1.0e9 |
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"mega" "M" |
1.0e6 |
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"kilo" "k" |
1.0e3 |
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"hecto" "h" |
1.0e2 |
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"deca" "da" |
1.0e1 |
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"deka" "da" |
1.0e1 |
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"deci" "d" |
1.0e-1 |
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"centi" "c" |
1.0e-2 |
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"milli" "m" |
1.0e-3 |
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"micro" "micro" |
1.0e-6 |
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"nano" "n" |
1.0e-9 |
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"pico" "p" |
1.0e-12 |
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"femto" "f" |
1.0e-15 |
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"atto" "a" |
1.0e-18 |
Functions
The following functions may be used in edit boxes.
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Syntax |
Return Type |
Expected Types |
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cos(expr) |
unitless |
angle |
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sin(expr) |
unitless |
angle |
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tan(expr) |
unitless |
angle |
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acos(expr) |
angle |
unitless |
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asin(expr) |
angle |
unitless |
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atan(expr) |
angle |
unitless |
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cosh(expr) |
unitless |
angle |
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sinh(expr) |
unitless |
angle |
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tanh(expr) |
unitless |
angle |
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acosh(expr) |
angle |
unitless |
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asinh(expr) |
angle |
unitless |
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atanh(expr) |
angle |
unitless |
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sqrt(expr) |
unit^1/2 |
any |
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sign(expr) |
unitless |
any Return 0 if negative, 1 if positive |
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exp(expr) |
unitless |
any Return exponential power. For example, returns 2.688E43 for 100. |
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floor(expr) |
ul |
ul Next lowest whole number |
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ceil(expr) |
ul |
ul Next highest whole number |
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round(expr) |
ul |
ul Closest whole number |
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abs(expr) |
any |
any |
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max(expr1;expr2) |
any |
any |
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min(expr1;expr2) |
any |
any |
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ln(expr) |
unitless |
unitless |
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log(expr) |
unitless |
unitless |
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pow(expr1; expr2) |
unit^expr2 |
any, and unitless respectively Can construct unit valid equation that can go invalid "pow(3.0; d12)". Decimal powers rounds at eighth decimal place. |
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random() |
unitless |
unitless |
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isolate(expr;unit;unit) |
Mechanical Desktop migration |