Noob: Curve from function

[taphonomist]

Hey all,

Newbie to the cad world, looking to be able to parametrically draw involutes. The hangup is that I don't know the best way to "plot" a parametric function of theta (angle of detachment). I've done this with the curve from table command and functions in Excel, but would like to make it parametric within SE if possible.

Thanks,
taphonomist

 

[fredericmenage]

Hi,

Do you have an example of the function you need ?

Anyway, using curve by table and Excel will remain the best method in my opinion.

Fred

 

[taphonomist]

Say r is your base circle radius, then I'm looking to generate a plot of the parametric equations (variable theta)

x(theta)=r(Sin(theta)+theta * Cos(theta)-1)
y(theta)=r(Sin(theta)- theta Cos(theta))

What I'm looking to do is to generate the curve created by varying theta.

taphonomist

 

[taphonomist]

This has a nice little animation with an involute being produced.

http://mathworld.wolfram.com/Involute.html

taphonomist

 

[fredericmenage]

Hi,

You could instead create a helical protrusion with a taper (button 'more') and after that create a sketch in which you include one of the involute shape edges.

http://img315.imageshack.us/my.php?image=engtips2qn.jpg

Fred