# Curve through equation?

#### Rajeev

##### New member
Does any body have some equation to defing curve using equation option?

#### Israr

##### Active member
try this,

x=4*sin(360*t)

y=4*cos(360*t)

z=sin(8*360*t)

and you will get a wavy washer curve.

Israra

##### Member
hello

try to find great answers through the forums of proecentral

karavasilis

#### tanm

##### New member
hi

for helical spring

cartision method

x=5*sin(360*10*t)

y=5*cos(360*10*t)

z=20*t

tanm

#### eddie

##### New member
Simple 2 axis datum curve using cartesian coordinates

y=sin(t*180)

x=t

#### kvision

##### Moderator
Does any body have some equation to defing curve using equation option?

Could you be a little more specific? What kind of curve are you trying to generate and in what coordinate system, cartesian, cylindrical, or spherecal.

#### Rajeev

##### New member
I am not creating any curve, i am trying to understand certain things about using curve in pro-e by equation. I want to understand the equations its self, can you help me kvision?

#### Nose Bleed

##### New member
Rajeev -

Are you trying to do a Variable Section Sweep???

#### Rajeev

##### New member
Yes. nose bleed, you have any suggestion?

#### kvision

##### Moderator
ProE creates curves by equation using a parameter t

t varies from 0 to 1 over the range of the inputs so that you can vary something line the angle by entering t*360 to get an evaluation from 0 to 360 instead of at a single point.

Basically you can take any equation interms of x,y,x and parametize it with t so that you can generate the curve intended. for a circle in the z plane

x = 4 * cos ( t * 360 ) (-4<= x <= 4)

y = 4 * sin ( t * 360 ) (-4 <= y <= 4)

z = 0

to make this a helix simply vary z such as

z=t*4 to make the height of the helix 4. (0<= t <= 1) and (0<= z <= 4)

to make a spiral add a damping function.

x = 4 * cos ( t * 360 ) *exp(-t)

y = 4 * sin ( t * 360 ) *exp(-t)

z = 4*t

Once you have the curve you need you can use it as the trajectory for your variable section swep. You can also use other types of curves as well if you can sketch your curve or create it as the intersection of 2 surfaces.

#### nawaz

##### New member
try following,

select spherical coordinate system

rho=sin(t*90)

theta=90*t

phi=t*360*25

=============

select spherical coordinate system

rho=cos(t*90)

theta=90*t

phi=t*360*25

#### Nose Bleed

##### New member
Rajeev -

Visit Karavasilis' article on Variable Section Sweeps -http://www.proecentral.com/portal/articles/articlesDetail.asp?id=25

good luck,