How to use algebraic equations and functions in the Inventor program parameters

The Inventor program has a very useful function that allows you to set various parameters with equations, in which you can use algebraic and trigonometric functions.

Equations can be simple, as well as with multiple algebraic operators, prefixes, and functions. Below is an example of a simple equation.

2 ul *(6+3)

The following complex equations use internal parameters such as pi.

(PI rad/5 ul +(25 deg *PI rad)/180 deg))

The following is a list of algebraic operators supported by Autodesk Inventor.

Operator

Value

+

summation

subtraction

%

остаток от деления числа с плавающей точкой

*

remainder of the floating-point number division

/

division

^

exponentiation

(

delimiter in an expression

)

delimiter in an expression

;

separator in functions with multiple arguments

The following table lists the unit prefixes supported by Autodesk Inventor.

Prefix

Symbol

Value

exa

E

1.0e18

peta

P

1.0e15

tera

T

1.0e12

giga

G

1.0e9

mega

M

1.0e6

kilo

k

1.0e3

hecto

h

1.0e2

deca

da

1.0e1

deci

d

1.0e-1

centi

c

1.0e-2

milli

m

1.0e-3

micro

micro

1.0-6

nano

n

1.0-9

Pi co

p

1.0e-12

femto

f

1.0-15

atto

a

1.0e-18

When you use unit prefixes in an equation, enter the prefix symbol. Do not enter the prefix itself. For example, an equation that includes the unit «nanometer» might look like this equation: 3.5 ul * 2.6 nm.

When you add the unit prefix for name to the meter unit, your equation is calculated based on the length of 2.6 nanometers.

Supported Functions

The following table lists the supported functions.

Syntax

Returns Unit Type

Expected Unit Type

cos(expr)

unitless

angle

sin(expr)

unitless

angle

tan(expr)

unitless

angle

acos(expr)

angle

unitless

asin(expr)

angle

unitless

atan(expr)

angle

unitless

cosh(expr)

unitless

angle

tanh(expr)

unitless

angle

acosh(expr)

angle

unitless

asinh(expr)

angle

unitless

sqrt(expr)

unit^1/2

any

sign(expr)

unitless

any (Return 0 if negative, 1 if positive.)

exp(expr)

unitless

any (Return exponential power of expression: for example, return 2 for 100, 3 for 1000, and so on.)

floor(expr)

unitless

unitless (Next lowest whole number.)

ceil(expr)

unitless

unitless (Next highest whole number.)

round(expr)

unitless

unitless (Closest whole number.)

abs(expr)

any

any

max(expr1;expr2)

any

any

min(expr1;expr2)

any

any

In(expr)

unitless

unitless

log(expr)

unitless

unitless

pow(expr1;expr2)

unit^expr2

any and unitless, respectively

random(expr)

unitless

unitless

isolate(expr;unit;unit)

any

any

Function names are case sensitive. Enter them exactly as they appear in the previous table.
 

The following table lists the reserved system parameters supported by Autodesk Inventor

Parameter

Value

PI

3.14159265358979323846264338328

E

2.71828182845904523536

The unit type that you use with an equation depends on the type of data that you are evaluating. For example, to evaluate a linear or angular value, you typically use a unit type of millimeters, inches, or degrees (mm, in, or deg).

Some equations must return a unitless value, for example, an equation to solve the number of occurrences in a pattern. You designate a unitless value with the characters ul. For example, 5 ul means that the equation has been evaluated and returned the number 5, as in the number of occurrences in a pattern.

Keep units consistent within equations containing parameters that represent different unit types. You can do this using the Isolate function. For example, to calculate the number of occurrences for a pattern that is based on one occurrence for each unit of a parameter named Width, your linear equation would be:

isolate(Width;mm;ul)

The number of Occurrences value in a dialog box requires a unitless (ul) result, but you are referencing the unit width, which is a linear value. Convert the Width parameter to a unitless value.

 

How to build a cone sweep in Inventor

We create a sketch of a thin-walled cone, in our case it is a cone with dimensions of an upper diameter of 200 mm, a bottom diameter of 400 mm, a wall thickness of 4 mm. Create a 3D object using the resulting sketch using the rotation command. Next, create a sketch in order to cut a slot 0.1 mm in the created cone. That is, it should look like a non-closed volume cone. The operation is cutting out the slits. Next, go to the medium sheet metal and set the thickness of the sheet in our case is 4 mm. Finally, execute the sweep command by selecting the surface of the cone.

How to build an auger with an arbitrary (step, path) helical blade in Inventor

Sometimes in the practice of an engineer there is a need to design a screw-type product whose helical surface has an arbitrary step. Consider the construction of this product. Create a sketch describing the trajectory of the future helical surface, this can be a spline given by the coordinates of points or a graph of any function.

Next we create a second sketch tangent to the first, in which we set the base of the auger in our case it is a pipe with an internal diameter of 30 mm.

Extrude the second sketch, we get the foundation of the future auger. Next, create a 3D sketch. In the 3D sketch editing environment, select the CURVE CURVE PROJECTION command, select the SURFACE PATTERN in the Output option, then select the surface itself, this is the pipe and the curve, this is the first sketch created.

The result of this command is the projection of the curve on the outer surface of the pipe. Create a 2D sketch that will determine the cross section of the screw auger blade. With the help of the SHIFT command, we squeeze out the section along the trajectory of the projected curve and the guide surface of the pipe. Preliminary it is necessary to choose the type of shift «Trajectory and guide surface». We get the result.