creating a spiral exponential arc.

I need to create a spiral exponential arc with a fix center, but the
radius of the arc will increase exponentially along the curve at every
5 degree increment. Is it possible to do this using an array or a
circular pattern. any advice would be appreciated.

 

SW has the ability to do a spiral, but if you have special requirements
like the exponential radius growth, you might have to write a little
equation for that. Might be easiest to write a polar equation and
convert to cartesian coordinates. I have a macro that you can type an
equation into, and it will draw a spline for you.

http://www.frontiernet.net/~mlombard/

go to the Macro library, and it is the eqcurve macro.

Good luck,

matt


(Judora) wrote in

 

can you write an equation for the curve?

 

"Judora"

you could use Excel to generate a file of points then "Curve through XYZ
points" to make a curve.

For more complex things, if you want to create calculated surfaces or if you
prefer VB programming to Excel formulas,
our free "MathSurf " macro
(http://www.dynabits.com/sw/free/macros/mathsurf/index.htm ) creates files
of points for curves and surfaces.
Then the free "SketchFile" macro
(http://www.dynabits.com/sw/free/macros/sketchfile/index.htm) creates
sketch(es) and even surfaces from the points.