Proe 2-d spiral datum curve equation

[Lhann]

I have seen several 2d spiral datum curve equations for Proengineer but they do not create a spiral curve that is tangent (normal to a plane) at the start and end of the spiral. Is there an equation that will achieve this?


Solidworks has a spiral tool that makes quick work of this. I will have to export from SW if i cannot generate something in Proe.


This is the equation that i have found in PTC support and other forums but this only creates a curve with end that are not tangent to the reference plane.


r= IR + t * (OR-IR)
theta=t * 360 * TURNS
z=0

 

[csusie]

You could alter the equations to change where the spiral started and stopped.


So if you needed to change the start angle of the spiral by -90 degrees then make


theta=t*360*TURNS-90


And for the stopping point, modify the number of turns accordingly. If you use a bit of math you will be able to get what you want.


If you cannot get equations to work, you could always use copy-paste special -rotate and trimming tools.
Edited by: csusie

 

[orac]

You could try the following


Use a cartesian coordinate system


radius = 10
increment = 10
nrofturns = 10


x = ( radius + increment * t * nrofturns ) * cos ( t * nrofturns * 360 )
y = ( radius + increment * t * nrofturns ) * sin ( t * nrofturns * 360 )



This gives a spiral that starts normal and ends normal on a plane (in this case the XZ plane)


Hope this can be of any use.


Best regards,


John Bijnens