
Re: Parametric equations
Jerry Steiger May 1, 2012 12:35 PM (in response to Mike Mongan)Mike,
I don't use equations, so I'm not going to be of much help, but perhaps my answer will prompt someone more knowledgeable to kick in.
What do you mean when you say parametric? I have seen people set up equations like x=f(t), y=g(t), z=h(t). Is that what you are referring to?
I don't believe SolidWorks knows about spherical or cylindrical coordinates, only Cartesion.
Jerry Steiger

Re: Parametric equations
Jason Kerns May 1, 2012 12:38 PM (in response to Mike Mongan)Is this what you are looking for?
Operator
Name
Notes
+
plus sign
addition

minus sign
subtraction
*
asterisk
multiplication
/
forward slash
division
^
caret
exponentiation
Function
sin (a)
sine
a is the angle; returns the sine ratio
cos (a)
cosine
a is the angle; returns the cosine ratio
tan (a)
tangent
a is the angle; returns the tangent ratio
sec (a)
secant
a is the angle; returns the secant ratio
cosec (a)
cosecant
a is the angle; returns the cosecant ratio
cotan (a)
cotangent
a is the angle; returns the cotangent ratio
arcsin (a)
inverse sine
a is the sine ratio; returns the angle
arccos (a)
inverse cosine
a is the cosine ratio; returns the angle
atn (a)
inverse tangent
a is the tangent ratio; returns the angle
arcsec (a)
inverse secant
a is the secant ratio; returns the angle
arccosec (a)
inverse cosecant
a is the cosecant ratio; returns the angle
arccotan (a)
inverse cotangent
a is the cotangent ratio; returns the angle
abs (a)
absolute value
returns the absolute value of a
exp (n)
exponential
returns e raised to the power of n
log (a)
logarithmic
returns the natural log of a to the base e
sqr (a)
square root
returns the square root of a
int (a)
integer
returns a as an integer
sgn (a)
sign
returns the sign of a as 1 or 1
For example: sgn(21) returns 1
Constant
pi
pi
ratio of the circumference to the diameter of a circle (3.14...)

Re: Parametric equations
Mike Mongan May 3, 2012 11:30 AM (in response to Mike Mongan)Hi Jerry and Jason,
Yes that is how a parametric equation is stated. And yes those are the standard functions. My old CAD system, Vectorworks which I still have, allows me to create a 3d surface using parametric equations. I have to write a script to do it but it works pretty good. I used it to create a turbine blade by formula. In the script I can enter commands to "place a point" etc with fields for x, y, z which is where the formula goes. Their commands are openly available. I see no such functionality in Solidworks which I though was a superior system when I bought it. So now I have to create my blades in Vectorworks and export the surface into Solidworks. It is a compund curve so I can't just draw it on a plane and project it.

Re: Parametric equations
Jerry Brian May 3, 2012 11:46 AM (in response to Mike Mongan)Start a new part.
Click the insert tab, select 3D sketch.
Now left click out in the work field, and select Equation driven curve ...
That's all i've got :)

Re: Parametric equations
Jeremy Feist May 3, 2012 12:42 PM (in response to Mike Mongan)yes, SW does not currently have an equation driven surface feature.
you can, as Jerry mentions, do an equation driven curve. and you could connect some of these in a loft or boundary surface/solid.

Re: Parametric equations
Mike Mongan May 17, 2012 2:30 PM (in response to Jeremy Feist)Yes, that does work and yes I was able to create a surface and solid. But when I entered the mirror equations to create the other side someting strange happened. There are two curves, differing only in their radius. One came out correct, the other has the correct start and end points but curves in the opposote direction. I've tried a dozen variations, no luck. Each of the three equations has a coefficient for the radius. That's the only difference between the two equations.

Re: Parametric equations
Jerry Brian May 17, 2012 2:42 PM (in response to Mike Mongan)There is a macro that you can get, I don't know if it would help, it's in this thread:


