Issue about Catia curve from equation 1

[PeterChen206]

Hello everyone,

I am using Catia curve from equation to build a curve. Here is the formula for x and y:
x = R*cos(2*PI*1rad*n*t)
y = R*sin(2*PI*1rad*n*t)

So n is a parameter I defined. When n is small, the curve is a circle. However, when n is large, like n=100, it is not a circle anymore. Instead the curve is very weird.

How can I make sure that the curve is still a circle even when n is large? Because mathematically it should be a circle no matter how large n is. Any help is appreciated.

 

[LWolf]

how exactly did you implement your equations?
with x and t as variables in a Law (real), and R and n as external parameters?...

regards,
LWolf

 

[PeterChen206]

LWolf, you are right. That is how I implemented. I even tried the following cases:
x=20mm*cos(2*PI*1rad*40*t)
y=20mm*sin(2*PI*1rad*40*t)
z=0mm*t
I changed 40 to 100, the curve is not a circle anymore.

 

[TudorM]

check this video

https://www.youtube.com/watch?v=MJfS2s3Agjc

 

[PeterChen206]

Yes, I saw that video before and I followed the instruction. The only thing I do not understand is why the curve is completely different when I want to have more revolutions.

 

[LWolf]

I get the circle... (as I should), no matter how many revolutions (N number).
can you post a picture when you vary z=N*t ?...

regards,
LWolf

 

[PeterChen206]

LWolf, below is my definition:
`x1`=25mm*cos(2*PI*1rad*100*`t`)
`y1`=25mm*sin(2*PI*1rad*100*`t`)
`z1`=0mm*`t`

The curve I got is shown below.

 

[LWolf]

yeah, seen the first picture.
did you use fog to define the laws?
could you humor me and show me a case when you vary the z

regards,
LWolf

 

[PeterChen206]

Below is the result with z=100mm*t
Do you think maybe there is some settings that I should make? The result is really weird.

 

[PeterChen206]

Yes, I used fog to define x,y,z. Then used curve from equation

 

[LWolf]

use real parameters, not lengths...


regards,
LWolf

 

[PeterChen206]

LWolf, what do you mean by 'not lengths'? Please see my x1 definition below. In my definition, the type of x1 and t is length and real, respectively.

 

[itsmyjob]

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Eric N.
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