Community
Inventor Forum
Welcome to Autodesk’s Inventor Forums. Share your knowledge, ask questions, and explore popular Inventor topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Equation Curve problems in polar coordinates

4 REPLIES 4
Reply
Message 1 of 5
spectoad
593 Views, 4 Replies

Equation Curve problems in polar coordinates

There seems to be a problem with the equation curve editor in polar coordinates. I am trying to draw a spiral pattern defined by the parametric equations {r(t) = t} and {theta(t) = (t-500)*PI} from t = 500 to t = 504. If I define these equations from t = 500 to t = 504 the curve generated is not actually the one defined by those equations, however if I define two separate curves from t = 500 to t = 502 and t = 502 to t = 504 the combination of these two curves is the result I'm looking for. Obviously these two methods should both produce the same curves, but in practice they definitely don't so I believe there is a bug somewhere in the equation curve programming. A work around would be that I could individually define these curves and then combine them to get the full curve, however since I would actually like to go from t = 500 to t = 1000 this would be far too time consuming to actually do. Thanks for your help!
4 REPLIES 4
Message 2 of 5
johnsonshiue
in reply to: spectoad

Hi! What Inventor release are you using? I just tried it on R2015 but I did not see the problem using the following equations.

 

r(t) = t

theta(t) = (t-500)*PI

 

500 <= t <= 504

Thanks!



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 3 of 5
WHolzwarth
in reply to: spectoad

Hmm. IMO, the result seems to depend on the document settings. Try this:

 

- Start a new IPT with Extras-> Document settings -> units -> Angle -> radiants

- Define now the equation like in the 1st picture. I think, you'll get the expected result

 

Polar EDC Part 1.jpg

 

Go back to Document settings and change Angle to deg. Define the next EDC like below. I think, you don't want that.

 

Polar EDC Part 2.jpg

 

Now change the 2nd equation like in the last picture. I think, that's your intented curve.

 

Polar EDC Part 3.jpg

 

Walter

 

Walter Holzwarth

EESignature

Message 4 of 5
spectoad
in reply to: WHolzwarth

Sorry I should have been more clear, the issue only seems to be when I'm using micron length scales. So the spiral pattern works correctly if r(t) = 1 m* t or r(t) = 1 mm* t, however when I use r(t) = 1 micron* t it gives me the incorrect result.
Message 5 of 5
WHolzwarth
in reply to: spectoad

Smiley WinkBest way for further discussions could be attaching your file.

Walter Holzwarth

EESignature

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report