Sine functions

[chrisjuk12]

Hi All,

I am new to using trig functions in inventor and was hoping someone could point me in the right direction.

I am trying to design a prism using snells law (n1.sin(x1)=n2.sin(x2)) and instead of having to do the math each time I would like to add an equation into the dimension box for the exit angle.

If I were to write the equation for finding the second angle it would look something like;

x2 = sin-1((n1 x sin(x1)/n2))

My known values are

n1 = 1

n2 = 1.472

x1 = variable from 10 to 40 degrees

I am entering;

arcsin((sin(dimension number)/1.472))

This however is saying 'expression cannot be evaluated'

Also, I am not skilled in creating macros etc so if it cannot be done through parameter equations then I will scrap the idea.

Thanks and kind reagdrs,

Chris

[JDMather]

What version of Inventor?

Are you using Equation Curves?

[cwhetten]

Hi and welcome to the forum!

The inverse sine function is called by:

asin( )

Also, watch your units.  All units must evaluate properly in your equations.

See the attached PDF for a list of all recognized functions in Inventor parameters and their syntax.  The PDF is a compilation of information from the following WikiHelp article:

http://wikihelp.autodesk.com/Inventor/enu/2014/Help/1283-Inventor1283/3876-Design_O3876/3886-Paramet...

Cameron Whetten
Inventor 2014

[karthur1]

ASIN (1*SIN(X)) =  X

From your equations:

X2 = 1 * X1/N2

Am I missing something obvious?